fmt: group_imports = "StdExternalCrate"

* shouldn't have used LLM to implement this...

.gitignore

@@ -5,3 +5,8 @@ target/
 # Profiling
 flamegraph*.svg
 perf.data*
+profile.json.gz
+prof.json
+*.cpuprofile
+*.cpuprofile.gz
+*v8.log*

.lazy.lua

@@ -3,12 +3,21 @@ vim.lsp.config("biome", {
     on_dir(vim.fn.getcwd())
   end
 })
+vim.lsp.config("eslint", {
+  settings = {
+    eslint = {
+      options = {
+        configFile = "./nix-js/runtime-ts/eslint.config.mts"
+      }
+    }
+  }
+})
 vim.lsp.config("rust_analyzer", {
   settings = {
     ["rust-analyzer"] = {
       cargo = {
         features = {
-          "daemon"
+          "inspector"
         }
       }
     }

Justfile

@@ -1,15 +1,31 @@
 [no-exit-message]
 @repl:
-  RUST_LOG=none,nix_js=debug cargo run --bin repl
+  cargo run -- repl
 
 [no-exit-message]
 @eval expr:
-  RUST_LOG=none,nix_js=debug cargo run --bin eval -- '{{expr}}'
+  cargo run -- eval --expr '{{expr}}'
 
 [no-exit-message]
 @replr:
-  RUST_LOG=info cargo run --bin repl --release
+  cargo run --release -- repl
 
 [no-exit-message]
 @evalr expr:
-  RUST_LOG=silent cargo run --bin eval --release -- '{{expr}}'
+  cargo run --release -- eval --expr '{{expr}}'
+
+[no-exit-message]
+@repli:
+  cargo run --release --features inspector -- --inspect-brk 127.0.0.1:9229 repl
+
+[no-exit-message]
+@evali expr:
+  cargo run --release --features inspector -- --inspect-brk 127.0.0.1:9229 eval --expr '{{expr}}'
+
+[no-exit-message]
+@replp:
+  cargo run --release --features prof -- repl
+
+[no-exit-message]
+@evalp expr:
+  cargo run --release --features prof -- eval --expr '{{expr}}'

biome.json

@@ -1,5 +1,5 @@
 {
-  "$schema": "https://biomejs.dev/schemas/2.3.9/schema.json",
+  "$schema": "https://biomejs.dev/schemas/2.3.14/schema.json",
   "vcs": {
     "enabled": true,
     "clientKind": "git",
@@ -20,10 +20,37 @@
   "linter": {
     "rules": {
       "style": {
-        "useNamingConvention": "warn"
+        "useNamingConvention": {
+          "level": "warn",
+          "options": {
+            "strictCase": false,
+            "conventions": [
+              {
+                "selector": { "kind": "objectLiteralProperty" },
+                "formats": ["camelCase", "PascalCase", "CONSTANT_CASE"]
+              },
+              {
+                "selector": { "kind": "typeProperty" },
+                "formats": ["camelCase", "snake_case"]
+              }
+            ]
+          }
+        }
       }
     }
   },
+  "overrides": [
+    {
+      "includes": ["**/global.d.ts"],
+      "linter": {
+        "rules": {
+          "style": {
+            "useNamingConvention": "off"
+          }
+        }
+      }
+    }
+  ],
   "javascript": {
     "formatter": {
       "arrowParentheses": "always",

default.nix

@@ -9,6 +9,7 @@ let
   flake = (
     import flake-compat {
       src = ./.;
+      copySourceTreeToStore = false;
     }
   );
 in

flake.lock

@@ -8,11 +8,11 @@
         "rust-analyzer-src": "rust-analyzer-src"
       },
       "locked": {
-        "lastModified": 1768892055,
-        "narHash": "sha256-zatCoDgFd0C8YEOztMeBcom6cka0GqJGfc0aAXvpktc=",
+        "lastModified": 1770966612,
+        "narHash": "sha256-S6k14z/JsDwX6zZyLucDBTOe/9RsvxH9GTUxHn2o4vc=",
         "owner": "nix-community",
         "repo": "fenix",
-        "rev": "81d6a7547e090f7e760b95b9cc534461f6045e43",
+        "rev": "e90d48dcfaebac7ea7a5687888a2d0733be26343",
         "type": "github"
       },
       "original": {
@@ -37,11 +37,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1768886240,
-        "narHash": "sha256-C2TjvwYZ2VDxYWeqvvJ5XPPp6U7H66zeJlRaErJKoEM=",
+        "lastModified": 1770841267,
+        "narHash": "sha256-9xejG0KoqsoKEGp2kVbXRlEYtFFcDTHjidiuX8hGO44=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "80e4adbcf8992d3fd27ad4964fbb84907f9478b0",
+        "rev": "ec7c70d12ce2fc37cb92aff673dcdca89d187bae",
         "type": "github"
       },
       "original": {
@@ -61,11 +61,11 @@
     "rust-analyzer-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1768816483,
-        "narHash": "sha256-bXeWgVkvxN76QEw12OaWFbRhO1yt+5QETz/BxBX4dk0=",
+        "lastModified": 1770934477,
+        "narHash": "sha256-GX0cINHhhzUbQHyDYN2Mc+ovb6Sx/4yrF95VVou9aW4=",
         "owner": "rust-lang",
         "repo": "rust-analyzer",
-        "rev": "1b8952b49fa10cae9020f0e46d0b8938563a6b64",
+        "rev": "931cd553be123b11db1435ac7ea5657e62e5e601",
         "type": "github"
       },
       "original": {

flake.nix

@@ -27,11 +27,14 @@
                 "rust-analyzer"
               ])
               cargo-outdated
+              cargo-machete
               lldb
               valgrind
               hyperfine
               just
               samply
+              jq
+              tokei
 
               nodejs
               nodePackages.npm

nix-js-macros/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2024"
 proc-macro = true
 
 [dependencies]
-convert_case = "0.8"
-quote = "1.0"
+convert_case = "0.11"
 proc-macro2 = "1.0"
+quote = "1.0"
 syn = { version = "2.0", features = ["full"] }

nix-js-macros/src/ir.rs

@@ -4,22 +4,22 @@
 //! an Intermediate Representation (IR) that follows a specific pattern. It generates:
 //! 1. An enum representing the different kinds of IR nodes.
 //! 2. Structs for each of the variants that have fields.
-//! 3. `Ref` and `Mut` versions of the main enum for ergonomic pattern matching on references.
-//! 4. `From` implementations to easily convert from a struct variant (e.g., `BinOp`) to the main enum (`Ir::BinOp`).
-//! 5. A `To[IrName]` trait to provide a convenient `.to_ir()` method on the variant structs.
+//! 3. `From` implementations to easily convert from a struct variant (e.g., `BinOp`) to the main enum (`Ir::BinOp`).
+//! 4. A `To[IrName]` trait to provide a convenient `.to_ir()` method on the variant structs.
 
 use convert_case::{Case, Casing};
 use proc_macro::TokenStream;
 use quote::{format_ident, quote};
 use syn::{
-    FieldsNamed, Ident, Token, Type, parenthesized,
+    Expr, ExprPath, FieldsNamed, GenericArgument, GenericParam, Generics, Ident, Path, PathSegment,
+    Token, Type, TypePath, parenthesized,
     parse::{Parse, ParseStream, Result},
     punctuated::Punctuated,
     token,
 };
 
 /// Represents one of the variants passed to the `ir!` macro.
-pub enum VariantInput {
+enum VariantInput {
     /// A unit-like variant, e.g., `Arg`.
     Unit(Ident),
     /// A tuple-like variant with one unnamed field, e.g., `ExprRef(ExprId)`.
@@ -29,11 +29,12 @@ pub enum VariantInput {
 }
 
 /// The top-level input for the `ir!` macro.
-pub struct MacroInput {
+struct MacroInput {
     /// The name of the main IR enum to be generated (e.g., `Ir`).
-    pub base_name: Ident,
+    base_name: Ident,
+    generics: Generics,
     /// The list of variants for the enum.
-    pub variants: Punctuated<VariantInput, Token![,]>,
+    variants: Punctuated<VariantInput, Token![,]>,
 }
 
 impl Parse for VariantInput {
@@ -64,13 +65,14 @@ impl Parse for VariantInput {
 
 impl Parse for MacroInput {
     fn parse(input: ParseStream) -> Result<Self> {
-        // The macro input is expected to be: `IrName, Variant1, Variant2, ...`
         let base_name = input.parse()?;
-        input.parse::<Token![,]>()?;
+        let generics = Generics::parse(input)?;
+        input.parse::<Token![;]>()?;
         let variants = Punctuated::parse_terminated(input)?;
 
         Ok(MacroInput {
             base_name,
+            generics,
             variants,
         })
     }
@@ -81,17 +83,39 @@ pub fn ir_impl(input: TokenStream) -> TokenStream {
     let parsed_input = syn::parse_macro_input!(input as MacroInput);
 
     let base_name = &parsed_input.base_name;
-    let ref_name = format_ident!("{}Ref", base_name);
-    let mut_name = format_ident!("{}Mut", base_name);
+    let generic_params = &parsed_input.generics.params;
+    let mk_ident_path = |ident| Path {
+        leading_colon: None,
+        segments: Punctuated::from_iter(std::iter::once(PathSegment {
+            ident,
+            arguments: Default::default(),
+        })),
+    };
+    let generic_args = {
+        generic_params
+            .iter()
+            .map(|arg| match arg {
+                GenericParam::Lifetime(lifetime) => {
+                    GenericArgument::Lifetime(lifetime.lifetime.clone())
+                }
+                GenericParam::Const(cnst) => GenericArgument::Const(Expr::Path(ExprPath {
+                    path: mk_ident_path(cnst.ident.clone()),
+                    attrs: Vec::new(),
+                    qself: None,
+                })),
+                GenericParam::Type(ty) => GenericArgument::Type(Type::Path(TypePath {
+                    path: mk_ident_path(ty.ident.clone()),
+                    qself: None,
+                })),
+            })
+            .collect::<Punctuated<_, Token![,]>>()
+    };
+    let where_clause = &parsed_input.generics.where_clause;
     let to_trait_name = format_ident!("To{}", base_name);
     let to_trait_fn_name = format_ident!("to_{}", base_name.to_string().to_case(Case::Snake));
 
     let mut enum_variants = Vec::new();
     let mut struct_defs = Vec::new();
-    let mut ref_variants = Vec::new();
-    let mut mut_variants = Vec::new();
-    let mut as_ref_arms = Vec::new();
-    let mut as_mut_arms = Vec::new();
     let mut span_arms = Vec::new();
     let mut from_impls = Vec::new();
     let mut to_trait_impls = Vec::new();
@@ -109,19 +133,15 @@ pub fn ir_impl(input: TokenStream) -> TokenStream {
                 });
 
                 enum_variants.push(quote! { #name(#inner_type) });
-                ref_variants.push(quote! { #name(&'a #inner_type) });
-                mut_variants.push(quote! { #name(&'a mut #inner_type) });
-                as_ref_arms.push(quote! { Self::#name(inner) => #ref_name::#name(inner) });
-                as_mut_arms.push(quote! { Self::#name(inner) => #mut_name::#name(inner) });
                 span_arms.push(quote! { Self::#name(inner) => inner.span });
                 from_impls.push(quote! {
-                    impl From<#inner_type> for #base_name {
+                    impl <#generic_params> From<#inner_type> for #base_name <#generic_args> #where_clause {
                         fn from(val: #inner_type) -> Self { #base_name::#name(val) }
                     }
                 });
                 to_trait_impls.push(quote! {
-                    impl #to_trait_name for #name {
-                        fn #to_trait_fn_name(self) -> #base_name { #base_name::from(self) }
+                    impl <#generic_params> #to_trait_name <#generic_args> for #name #where_clause {
+                        fn #to_trait_fn_name(self) -> #base_name <#generic_args> { #base_name::from(self) }
                     }
                 });
             }
@@ -138,25 +158,24 @@ pub fn ir_impl(input: TokenStream) -> TokenStream {
 
                 let inner_type = name.clone();
                 enum_variants.push(quote! { #name(#inner_type) });
-                ref_variants.push(quote! { #name(&'a #inner_type) });
-                mut_variants.push(quote! { #name(&'a mut #inner_type) });
-                as_ref_arms.push(quote! { Self::#name(inner) => #ref_name::#name(inner) });
-                as_mut_arms.push(quote! { Self::#name(inner) => #mut_name::#name(inner) });
                 span_arms.push(quote! { Self::#name(inner) => inner.span });
                 from_impls.push(quote! {
-                    impl From<#inner_type> for #base_name {
+                    impl <#generic_params> From<#inner_type> for #base_name <#generic_args> #where_clause {
                         fn from(val: #inner_type) -> Self { #base_name::#name(val) }
                     }
                 });
                 to_trait_impls.push(quote! {
-                    impl #to_trait_name for #name {
-                        fn #to_trait_fn_name(self) -> #base_name { #base_name::from(self) }
+                    impl <#generic_params> #to_trait_name <#generic_args> for #name #where_clause {
+                        fn #to_trait_fn_name(self) -> #base_name <#generic_args> { #base_name::from(self) }
                     }
                 });
             }
             VariantInput::Struct(name, mut fields) => {
                 let inner_type = name.clone();
 
+                fields.named.iter_mut().for_each(|field| {
+                    field.vis = syn::Visibility::Public(syn::token::Pub::default());
+                });
                 fields.named.push(syn::Field {
                     attrs: vec![],
                     vis: syn::Visibility::Public(syn::token::Pub::default()),
@@ -168,22 +187,18 @@ pub fn ir_impl(input: TokenStream) -> TokenStream {
 
                 struct_defs.push(quote! {
                     #[derive(Debug)]
-                    pub struct #name #fields
+                    pub struct #name <#generic_params> #where_clause #fields
                 });
-                enum_variants.push(quote! { #name(#inner_type) });
-                ref_variants.push(quote! { #name(&'a #inner_type) });
-                mut_variants.push(quote! { #name(&'a mut #inner_type) });
-                as_ref_arms.push(quote! { Self::#name(inner) => #ref_name::#name(inner) });
-                as_mut_arms.push(quote! { Self::#name(inner) => #mut_name::#name(inner) });
+                enum_variants.push(quote! { #name(#inner_type <#generic_args>) });
                 span_arms.push(quote! { Self::#name(inner) => inner.span });
                 from_impls.push(quote! {
-                    impl From<#inner_type> for #base_name {
-                        fn from(val: #inner_type) -> Self { #base_name::#name(val) }
+                    impl <#generic_params> From<#inner_type <#generic_args>> for #base_name <#generic_args> #where_clause {
+                        fn from(val: #inner_type <#generic_args>) -> Self { #base_name::#name(val) }
                     }
                 });
                 to_trait_impls.push(quote! {
-                    impl #to_trait_name for #name {
-                        fn #to_trait_fn_name(self) -> #base_name { #base_name::from(self) }
+                    impl <#generic_params> #to_trait_name <#generic_args> for #name <#generic_args> #where_clause {
+                        fn #to_trait_fn_name(self) -> #base_name <#generic_args> { #base_name::from(self) }
                     }
                 });
             }
@@ -193,41 +208,15 @@ pub fn ir_impl(input: TokenStream) -> TokenStream {
     // Assemble the final generated code.
     let expanded = quote! {
         /// The main IR enum, generated by the `ir!` macro.
-        #[derive(Debug, IsVariant, Unwrap, TryUnwrap)]
-        pub enum #base_name {
+        #[derive(Debug)]
+        pub enum #base_name <#generic_params> #where_clause {
             #( #enum_variants ),*
         }
 
         // The struct definitions for the enum variants.
         #( #struct_defs )*
 
-        /// An immutable reference version of the IR enum.
-        #[derive(Debug, IsVariant, Unwrap, TryUnwrap)]
-        pub enum #ref_name<'a> {
-            #( #ref_variants ),*
-        }
-
-        /// A mutable reference version of the IR enum.
-        #[derive(Debug, IsVariant, Unwrap, TryUnwrap)]
-        pub enum #mut_name<'a> {
-            #( #mut_variants ),*
-        }
-
-        impl #base_name {
-            /// Converts a `&Ir` into a `IrRef`.
-            pub fn as_ref(&self) -> #ref_name<'_> {
-                match self {
-                    #( #as_ref_arms ),*
-                }
-            }
-
-            /// Converts a `&mut Ir` into a `IrMut`.
-            pub fn as_mut(&mut self) -> #mut_name<'_> {
-                match self {
-                    #( #as_mut_arms ),*
-                }
-            }
-
+        impl <#generic_params> #base_name <#generic_args> #where_clause {
             pub fn span(&self) -> rnix::TextRange {
                 match self {
                     #( #span_arms ),*
@@ -239,9 +228,9 @@ pub fn ir_impl(input: TokenStream) -> TokenStream {
         #( #from_impls )*
 
         /// A trait for converting a variant struct into the main IR enum.
-        pub trait #to_trait_name {
+        pub trait #to_trait_name <#generic_params> #where_clause {
             /// Performs the conversion.
-            fn #to_trait_fn_name(self) -> #base_name;
+            fn #to_trait_fn_name(self) -> #base_name <#generic_args>;
         }
 
         // Implement the `ToIr` trait for each variant struct.

nix-js/Cargo.toml

@@ -4,19 +4,18 @@ version = "0.1.0"
 edition = "2024"
 build = "build.rs"
 
-[features]
-default = ["daemon"]
-daemon = ["dep:tokio", "dep:nix-compat"]
-
 [dependencies]
 mimalloc = "0.1"
 
-tokio = { version = "1.41", features = ["rt-multi-thread", "sync", "net", "io-util"], optional = true }
-nix-compat = { git = "https://git.snix.dev/snix/snix.git", version = "0.1.0", features = ["wire", "async"], optional = true }
+tokio = { version = "1.41", features = ["rt-multi-thread", "sync", "net", "io-util"] }
+nix-compat = { git = "https://git.snix.dev/snix/snix.git", version = "0.1.0", features = ["wire", "async"] }
 
 # REPL
 anyhow = "1.0"
-rustyline = "14.0"
+rustyline = "17.0"
+
+# CLI
+clap = { version = "4", features = ["derive"] }
 
 # Logging
 tracing = "0.1"
@@ -27,8 +26,8 @@ thiserror = "2"
 miette = { version = "7.4", features = ["fancy"] }
 
 hashbrown = "0.16"
-petgraph = "0.8"
 string-interner = "0.19"
+bumpalo = { version = "3.20", features = ["allocator-api2", "boxed", "collections"] }
 
 rust-embed="8.11"
 
@@ -36,35 +35,55 @@ itertools = "0.14"
 
 regex = "1.11"
 
-deno_core = "0.376"
+deno_core = "0.385"
 deno_error = "0.7"
 
 nix-nar = "0.3"
 sha2 = "0.10"
+sha1 = "0.10"
+md5 = "0.8"
 hex = "0.4"
 
 base64 = "0.22"
 
-# Fetcher dependencies
-reqwest = { version = "0.12", features = ["blocking", "rustls-tls"], default-features = false }
+reqwest = { version = "0.13", features = ["blocking", "rustls"], default-features = false }
 tar = "0.4"
 flate2 = "1.0"
 xz2 = "0.1"
-bzip2 = "0.5"
-zip = "2.2"
+bzip2 = "0.6"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
-dirs = "5.0"
+# spec 1.0.0
+toml = "0.9.9"
+dirs = "6.0"
 tempfile = "3.24"
-rusqlite = { version = "0.33", features = ["bundled"] }
+rusqlite = { version = "0.38", features = ["bundled"] }
 
-rnix = "0.12"
-rowan = "0.15"
+rnix = "0.14"
+rowan = "0.16"
 
 nix-js-macros = { path = "../nix-js-macros" }
+ere = "0.2.4"
+num_enum = "0.7.5"
+tap = "1.0.1"
+
+# Inspector (optional)
+fastwebsockets = { version = "0.10", features = ["upgrade"], optional = true }
+hyper = { version = "1", features = ["http1", "server"], optional = true }
+hyper-util = { version = "0.1", features = ["tokio"], optional = true }
+http-body-util = { version = "0.1", optional = true }
+http = { version = "1", optional = true }
+uuid = { version = "1", features = ["v4"], optional = true }
+ghost-cell = "0.2.6"
+colored = "3.1.1"
+
+[features]
+inspector = ["dep:fastwebsockets", "dep:hyper", "dep:hyper-util", "dep:http-body-util", "dep:http", "dep:uuid"]
+prof = []
 
 [dev-dependencies]
-criterion = { version = "0.5", features = ["html_reports"] }
+criterion = { version = "0.8", features = ["html_reports"] }
+test-log = { version = "0.2", features = ["trace"] }
 
 [[bench]]
 name = "basic_ops"

nix-js/benches/basic_ops.rs

@@ -1,6 +1,8 @@
 mod utils;
 
-use criterion::{Criterion, black_box, criterion_group, criterion_main};
+use std::hint::black_box;
+
+use criterion::{Criterion, criterion_group, criterion_main};
 use utils::eval;
 
 fn bench_arithmetic(c: &mut Criterion) {

nix-js/benches/builtins.rs

@@ -1,6 +1,8 @@
 mod utils;
 
-use criterion::{Criterion, black_box, criterion_group, criterion_main};
+use std::hint::black_box;
+
+use criterion::{Criterion, criterion_group, criterion_main};
 use utils::eval;
 
 fn bench_builtin_math(c: &mut Criterion) {

nix-js/benches/compile_time.rs

@@ -1,6 +1,8 @@
 mod utils;
 
-use criterion::{Criterion, black_box, criterion_group, criterion_main};
+use std::hint::black_box;
+
+use criterion::{Criterion, criterion_group, criterion_main};
 use nix_js::context::Context;
 use utils::compile;
 

nix-js/benches/thunk_scope.rs

@@ -1,6 +1,8 @@
 mod utils;
 
-use criterion::{Criterion, black_box, criterion_group, criterion_main};
+use std::hint::black_box;
+
+use criterion::{Criterion, criterion_group, criterion_main};
 use utils::eval;
 
 fn bench_non_recursive(c: &mut Criterion) {

nix-js/benches/utils.rs

@@ -7,19 +7,19 @@ use nix_js::value::Value;
 pub fn eval(expr: &str) -> Value {
     Context::new()
         .unwrap()
-        .eval_code(Source::new_eval(expr.into()).unwrap())
+        .eval(Source::new_eval(expr.into()).unwrap())
         .unwrap()
 }
 
 pub fn eval_result(expr: &str) -> Result<Value> {
     Context::new()
         .unwrap()
-        .eval_code(Source::new_eval(expr.into()).unwrap())
+        .eval(Source::new_eval(expr.into()).unwrap())
 }
 
 pub fn compile(expr: &str) -> String {
     Context::new()
         .unwrap()
-        .compile_code(Source::new_eval(expr.into()).unwrap())
+        .compile(Source::new_eval(expr.into()).unwrap())
         .unwrap()
 }

nix-js/runtime-ts/eslint.config.mts

@@ -0,0 +1,20 @@
+import js from "@eslint/js";
+import { defineConfig } from "eslint/config";
+import globals from "globals";
+import tseslint from "typescript-eslint";
+
+export default defineConfig([
+  js.configs.recommended,
+  ...tseslint.configs.recommended,
+  {
+    files: ["**/*.{js,mjs,cjs,ts,mts,cts}"],
+    languageOptions: { globals: globals.es2022 },
+    rules: {
+      "no-unused-vars": "off",
+      "@typescript-eslint/no-unused-vars": ["error", { varsIgnorePattern: "^_", argsIgnorePattern: "^_" }],
+    },
+  },
+  {
+    ignores: ["dist/**/*"],
+  },
+]);

nix-js/runtime-ts/package.json

@@ -3,15 +3,20 @@
   "version": "0.1.0",
   "private": true,
   "scripts": {
+    "check": "tsc --noEmit && npx eslint && biome check",
     "typecheck": "tsc --noEmit",
     "build": "node build.mjs",
     "dev": "npm run typecheck && npm run build"
   },
   "devDependencies": {
     "esbuild": "^0.24.2",
-    "typescript": "^5.7.2"
+    "eslint": "^9.39.2",
+    "typescript": "^5.7.2",
+    "typescript-eslint": "^8.55.0",
+    "jiti": "^2.6.1"
   },
   "dependencies": {
+    "globals": "^17.3.0",
     "js-sdsl": "^4.4.2"
   }
 }

nix-js/runtime-ts/src/builtins/arithmetic.ts

@@ -1,30 +1,26 @@
-/**
- * Arithmetic builtin functions
- */
-
-import type { NixBool, NixInt, NixNumber, NixValue } from "../types";
-import { forceNumeric, coerceNumeric, forceInt } from "../type-assert";
 import { op } from "../operators";
+import { coerceNumeric, forceInt, forceNumeric } from "../type-assert";
+import type { NixBool, NixInt, NixNumber, NixValue } from "../types";
 
 export const add =
   (a: NixValue) =>
   (b: NixValue): bigint | number => {
     const [av, bv] = coerceNumeric(forceNumeric(a), forceNumeric(b));
-    return (av as any) + (bv as any);
+    return (av as never) + (bv as never);
   };
 
 export const sub =
   (a: NixValue) =>
   (b: NixValue): bigint | number => {
     const [av, bv] = coerceNumeric(forceNumeric(a), forceNumeric(b));
-    return (av as any) - (bv as any);
+    return (av as never) - (bv as never);
   };
 
 export const mul =
   (a: NixValue) =>
   (b: NixValue): bigint | number => {
     const [av, bv] = coerceNumeric(forceNumeric(a), forceNumeric(b));
-    return (av as any) * (bv as any);
+    return (av as never) * (bv as never);
   };
 
 export const div =
@@ -36,10 +32,9 @@ export const div =
       throw new RangeError("Division by zero");
     }
 
-    return (av as any) / (bv as any);
+    return (av as never) / (bv as never);
   };
 
-// Bitwise operations - only for integers
 export const bitAnd =
   (a: NixValue) =>
   (b: NixValue): NixInt => {

nix-js/runtime-ts/src/builtins/attrs.ts

@@ -1,15 +1,12 @@
-/**
- * Attribute set operation builtin functions
- */
-
-import type { NixValue, NixAttrs, NixList } from "../types";
-import { forceAttrs, forceStringValue, forceFunction, forceList } from "../type-assert";
+import { mkPos, select } from "../helpers";
 import { createThunk } from "../thunk";
+import { forceAttrs, forceFunction, forceList, forceStringValue } from "../type-assert";
+import { ATTR_POSITIONS, type NixAttrs, type NixList, type NixValue } from "../types";
 
-export const attrNames = (set: NixValue): string[] => Object.keys(forceAttrs(set)).sort();
+export const attrNames = (set: NixValue): string[] => Array.from(forceAttrs(set).keys()).sort();
 
 export const attrValues = (set: NixValue): NixValue[] =>
-  Object.entries(forceAttrs(set))
+  Array.from(forceAttrs(set).entries())
     .sort(([a], [b]) => {
       if (a < b) {
         return -1;
@@ -24,21 +21,24 @@ export const attrValues = (set: NixValue): NixValue[] =>
 export const getAttr =
   (s: NixValue) =>
   (set: NixValue): NixValue =>
-    forceAttrs(set)[forceStringValue(s)];
+    select(forceAttrs(set), [s]);
 
 export const hasAttr =
   (s: NixValue) =>
   (set: NixValue): boolean =>
-    Object.hasOwn(forceAttrs(set), forceStringValue(s));
+    forceAttrs(set).has(forceStringValue(s));
 
 export const mapAttrs =
   (f: NixValue) =>
   (attrs: NixValue): NixAttrs => {
     const forcedAttrs = forceAttrs(attrs);
     const forcedF = forceFunction(f);
-    const newAttrs: NixAttrs = {};
-    for (const key in forcedAttrs) {
-      newAttrs[key] = createThunk(() => forceFunction(forcedF(key))(forcedAttrs[key]), "created by mapAttrs");
+    const newAttrs: NixAttrs = new Map();
+    for (const [key, val] of forcedAttrs) {
+      newAttrs.set(
+        key,
+        createThunk(() => forceFunction(forcedF(key))(val), "created by mapAttrs"),
+      );
     }
     return newAttrs;
   };
@@ -46,25 +46,20 @@ export const mapAttrs =
 export const removeAttrs =
   (attrs: NixValue) =>
   (list: NixValue): NixAttrs => {
-    const new_attrs: NixAttrs = {};
-    const forced_attrs = forceAttrs(attrs);
-    const forced_list = forceList(list);
-    const keys_to_remove = new Set(forced_list.map(forceStringValue));
-
-    for (const key in forced_attrs) {
-      if (!keys_to_remove.has(key)) {
-        new_attrs[key] = forced_attrs[key];
+    const newAttrs: NixAttrs = new Map(forceAttrs(attrs));
+    const forcedList = forceList(list);
+    for (const item of forcedList) {
+      newAttrs.delete(forceStringValue(item));
     }
-    }
-    return new_attrs;
+    return newAttrs;
   };
 
 export const listToAttrs = (e: NixValue): NixAttrs => {
-  const attrs: NixAttrs = {};
-  const forced_e = [...forceList(e)].reverse();
-  for (const obj of forced_e) {
+  const attrs: NixAttrs = new Map();
+  const forcedE = [...forceList(e)].reverse();
+  for (const obj of forcedE) {
     const item = forceAttrs(obj);
-    attrs[forceStringValue(item.name)] = item.value;
+    attrs.set(forceStringValue(select(item, ["name"])), select(item, ["value"]));
   }
   return attrs;
 };
@@ -74,10 +69,18 @@ export const intersectAttrs =
   (e2: NixValue): NixAttrs => {
     const f1 = forceAttrs(e1);
     const f2 = forceAttrs(e2);
-    const attrs: NixAttrs = {};
-    for (const key of Object.keys(f2)) {
-      if (Object.hasOwn(f1, key)) {
-        attrs[key] = f2[key];
+    const attrs: NixAttrs = new Map();
+    if (f1.size < f2.size) {
+      for (const [key] of f1) {
+        if (f2.has(key)) {
+          attrs.set(key, f2.get(key) as NixValue);
+        }
+      }
+    } else {
+      for (const [key] of f2) {
+        if (f1.has(key)) {
+          attrs.set(key, f2.get(key) as NixValue);
+        }
       }
     }
     return attrs;
@@ -88,20 +91,20 @@ export const catAttrs =
   (list: NixValue): NixList => {
     const key = forceStringValue(attr);
     return forceList(list)
-      .map((set) => forceAttrs(set)[key])
-      .filter((val) => val !== undefined);
+      .map((set) => forceAttrs(set).get(key))
+      .filter((val) => val !== undefined) as NixList;
   };
 
 export const groupBy =
   (f: NixValue) =>
   (list: NixValue): NixAttrs => {
-    const attrs: NixAttrs = {};
-    const forced_f = forceFunction(f);
-    const forced_list = forceList(list);
-    for (const elem of forced_list) {
-      const key = forceStringValue(forced_f(elem));
-      if (!attrs[key]) attrs[key] = [];
-      (attrs[key] as NixList).push(elem);
+    const attrs: NixAttrs = new Map();
+    const forcedF = forceFunction(f);
+    const forcedList = forceList(list);
+    for (const elem of forcedList) {
+      const key = forceStringValue(forcedF(elem));
+      if (!attrs.has(key)) attrs.set(key, []);
+      (attrs.get(key) as NixList).push(elem);
     }
     return attrs;
   };
@@ -111,29 +114,26 @@ export const zipAttrsWith =
   (list: NixValue): NixValue => {
     const listForced = forceList(list);
 
-    // Map to collect all values for each attribute name
     const attrMap = new Map<string, NixValue[]>();
 
-    // Iterate through each attribute set in the list
     for (const item of listForced) {
       const attrs = forceAttrs(item);
 
-      // Collect all attribute names and their values
-      for (const [key, value] of Object.entries(attrs)) {
+      for (const [key, value] of attrs) {
         if (!attrMap.has(key)) {
           attrMap.set(key, []);
         }
-        attrMap.get(key)!.push(value);
+        (attrMap.get(key) as NixValue[]).push(value);
       }
     }
 
-    // Build the result attribute set
-    const result: Record<string, NixValue> = {};
+    const result: NixAttrs = new Map();
 
     for (const [name, values] of attrMap.entries()) {
-      // Apply f to name and values list
-      // f is curried: f name values
-      result[name] = createThunk(() => forceFunction(forceFunction(f)(name))(values));
+      result.set(
+        name,
+        createThunk(() => forceFunction(forceFunction(f)(name))(values)),
+      );
     }
 
     return result;
@@ -145,15 +145,15 @@ export const unsafeGetAttrPos =
     const name = forceStringValue(attrName);
     const attrs = forceAttrs(attrSet);
 
-    if (!(name in attrs)) {
+    if (!attrs.has(name)) {
       return null;
     }
 
-    const positions = (attrs as any)[Nix.ATTR_POSITIONS];
-    if (!positions || !(name in positions)) {
+    const positions = attrs[ATTR_POSITIONS];
+    if (!positions || !positions.has(name)) {
       return null;
     }
 
-    const span = positions[name];
-    return Nix.mkPos(span);
+    const span = positions.get(name) as number;
+    return mkPos(span);
   };

nix-js/runtime-ts/src/builtins/context.ts

@@ -1,15 +1,15 @@
-import type { NixValue, NixAttrs, NixString } from "../types";
-import { isStringWithContext } from "../types";
-import { forceString, forceAttrs, forceList, forceStringValue } from "../type-assert";
-import { force } from "../thunk";
 import {
-  type NixStringContext,
-  getStringValue,
-  getStringContext,
-  mkStringWithContext,
   decodeContextElem,
+  getStringContext,
+  getStringValue,
+  mkStringWithContext,
+  type NixStringContext,
   parseContextToInfoMap,
 } from "../string-context";
+import { force } from "../thunk";
+import { forceAttrs, forceList, forceString, forceStringValue } from "../type-assert";
+import type { NixAttrs, NixString, NixValue } from "../types";
+import { isStringWithContext } from "../types";
 
 /**
  * builtins.hasContext - Check if string has context
@@ -113,20 +113,20 @@ export const getContext = (value: NixValue): NixAttrs => {
   const context = getStringContext(s);
 
   const infoMap = parseContextToInfoMap(context);
-  const result: NixAttrs = {};
+  const result: NixAttrs = new Map();
 
   for (const [path, info] of infoMap) {
-    const attrs: NixAttrs = {};
+    const attrs: NixAttrs = new Map();
     if (info.path) {
-      attrs["path"] = true;
+      attrs.set("path", true);
     }
     if (info.allOutputs) {
-      attrs["allOutputs"] = true;
+      attrs.set("allOutputs", true);
     }
     if (info.outputs.length > 0) {
-      attrs["outputs"] = info.outputs;
+      attrs.set("outputs", info.outputs);
     }
-    result[path] = attrs;
+    result.set(path, attrs);
   }
 
   return result;
@@ -154,22 +154,22 @@ export const appendContext =
     const ctxAttrs = forceAttrs(ctxValue);
     const newContext: NixStringContext = new Set(existingContext);
 
-    for (const [path, infoVal] of Object.entries(ctxAttrs)) {
+    for (const [path, infoVal] of ctxAttrs) {
       if (!path.startsWith("/nix/store/")) {
         throw new Error(`context key '${path}' is not a store path`);
       }
 
-      const info = forceAttrs(infoVal);
+      const info = forceAttrs(infoVal as NixValue);
 
-      if ("path" in info) {
-        const pathVal = force(info["path"]);
+      if (info.has("path")) {
+        const pathVal = force(info.get("path") as NixValue);
         if (pathVal === true) {
           newContext.add(path);
         }
       }
 
-      if ("allOutputs" in info) {
-        const allOutputs = force(info["allOutputs"]);
+      if (info.has("allOutputs")) {
+        const allOutputs = force(info.get("allOutputs") as NixValue);
         if (allOutputs === true) {
           if (!path.endsWith(".drv")) {
             throw new Error(
@@ -180,8 +180,8 @@ export const appendContext =
         }
       }
 
-      if ("outputs" in info) {
-        const outputs = forceList(info["outputs"]);
+      if (info.has("outputs")) {
+        const outputs = forceList(info.get("outputs") as NixValue);
         if (outputs.length > 0 && !path.endsWith(".drv")) {
           throw new Error(
             `tried to add derivation output context of ${path}, which is not a derivation, to a string`,

nix-js/runtime-ts/src/builtins/conversion.ts

@@ -2,72 +2,47 @@
  * Conversion and serialization builtin functions
  */
 
-import type { NixValue, NixString, NixPath } from "../types";
-import { isStringWithContext, isNixPath } from "../types";
-import { force } from "../thunk";
-import { type NixStringContext, mkStringWithContext, addBuiltContext } from "../string-context";
-import { forceFunction } from "../type-assert";
-import { nixValueToJson } from "../conversion";
+import {
+  addBuiltContext,
+  mkStringWithContext,
+  type NixStringContext,
+  StringWithContext,
+} from "../string-context";
+import { force, isThunk } from "../thunk";
+import { forceFunction, forceStringNoCtx } from "../type-assert";
+import type { NixString, NixValue } from "../types";
+import { isNixPath, isStringWithContext, NixPath } from "../types";
 import { isAttrs, isPath, typeOf } from "./type-check";
 
-const convertJsonToNix = (json: unknown): NixValue => {
-  if (json === null) {
-    return null;
-  }
-  if (typeof json === "boolean") {
-    return json;
-  }
-  if (typeof json === "number") {
-    if (Number.isInteger(json)) {
-      return BigInt(json);
-    }
-    return json;
-  }
-  if (typeof json === "string") {
-    return json;
-  }
-  if (Array.isArray(json)) {
-    return json.map(convertJsonToNix);
-  }
-  if (typeof json === "object") {
-    const result: Record<string, NixValue> = {};
-    for (const [key, value] of Object.entries(json)) {
-      result[key] = convertJsonToNix(value);
-    }
-    return result;
-  }
-  throw new TypeError(`unsupported JSON value type: ${typeof json}`);
-};
-
 export const fromJSON = (e: NixValue): NixValue => {
   const str = force(e);
   if (typeof str !== "string" && !isStringWithContext(str)) {
     throw new TypeError(`builtins.fromJSON: expected a string, got ${typeOf(str)}`);
   }
   const jsonStr = isStringWithContext(str) ? str.value : str;
-  try {
-    const parsed = JSON.parse(jsonStr);
-    return convertJsonToNix(parsed);
-  } catch (err) {
-    throw new SyntaxError(`builtins.fromJSON: ${err instanceof Error ? err.message : String(err)}`);
-  }
+  return Deno.core.ops.op_from_json(jsonStr) as NixValue;
 };
 
-export const fromTOML = (e: NixValue): never => {
-  throw new Error("Not implemented: fromTOML");
+export const fromTOML = (e: NixValue): NixValue => {
+  const toml = forceStringNoCtx(e);
+  return Deno.core.ops.op_from_toml(toml) as NixValue;
 };
 
 export const toJSON = (e: NixValue): NixString => {
   const context: Set<string> = new Set();
-  const string = JSON.stringify(nixValueToJson(e, new Set(), context));
+  const string = JSON.stringify(nixValueToJson(e, true, context, true));
   if (context.size === 0) {
     return string;
   }
   return mkStringWithContext(string, context);
 };
 
-export const toXML = (e: NixValue): never => {
-  throw new Error("Not implemented: toXML");
+export const toXML = (e: NixValue): NixString => {
+  const [xml, context] = Deno.core.ops.op_to_xml(force(e));
+  if (context.length === 0) {
+    return xml;
+  }
+  return mkStringWithContext(xml, new Set(context));
 };
 
 /**
@@ -120,7 +95,7 @@ export const coerceToString = (
   value: NixValue,
   mode: StringCoercionMode,
   copyToStore: boolean = false,
-  outContext?: NixStringContext,
+  outContext: NixStringContext,
 ): string => {
   const v = force(value);
 
@@ -130,11 +105,9 @@ export const coerceToString = (
   }
 
   if (isStringWithContext(v)) {
-    if (outContext) {
     for (const elem of v.context) {
       outContext.add(elem);
     }
-    }
     return v.value;
   }
 
@@ -143,41 +116,38 @@ export const coerceToString = (
     if (copyToStore) {
       const pathStr = v.value;
       const storePath = Deno.core.ops.op_copy_path_to_store(pathStr);
-      if (outContext) {
       outContext.add(storePath);
-      }
       return storePath;
     }
     return v.value;
   }
 
   if (typeof v === "object" && v !== null && !Array.isArray(v)) {
-    // First, try the __toString method if present
-    // This allows custom types to define their own string representation
-    if ("__toString" in v) {
-      // Force the method in case it's a thunk
-      const toStringMethod = forceFunction(v.__toString);
+    if (v instanceof Map) {
+      if (v.has("__toString")) {
+        const toStringMethod = forceFunction(v.get("__toString") as NixValue);
         const result = force(toStringMethod(v));
-      // Recursively coerceToString
         return coerceToString(result, mode, copyToStore, outContext);
       }
 
-    // If no __toString, try outPath (used for derivations and store paths)
-    // This allows derivation objects like { outPath = "/nix/store/..."; } to be coerced
-    if ("outPath" in v) {
-      // Recursively coerce the outPath value
-      const outPath = coerceToString(v.outPath, mode, copyToStore, outContext);
-      if ("type" in v && v.type === "derivation" && "drvPath" in v) {
-        const drvPath = force(v.drvPath);
-        if (typeof drvPath === "string" && outContext) {
-          const outputName = "outputName" in v ? String(force(v.outputName)) : "out";
-          addBuiltContext(outContext, drvPath, outputName);
+      if (v.has("outPath")) {
+        const outPath = coerceToString(v.get("outPath") as NixValue, mode, copyToStore, outContext);
+        if (v.has("type") && v.get("type") === "derivation" && v.has("drvPath") && outContext) {
+          const drvPathValue = force(v.get("drvPath") as NixValue);
+          const drvPathStr = isStringWithContext(drvPathValue)
+            ? drvPathValue.value
+            : typeof drvPathValue === "string"
+              ? drvPathValue
+              : null;
+          if (drvPathStr) {
+            const outputName = v.has("outputName") ? String(force(v.get("outputName") as NixValue)) : "out";
+            addBuiltContext(outContext, drvPathStr, outputName);
           }
         }
         return outPath;
       }
+    }
 
-    // Attribute sets without __toString or outPath cannot be coerced
     throw new TypeError(`cannot coerce ${typeOf(v)} to a string`);
   }
 
@@ -282,14 +252,14 @@ export const coerceToStringWithContext = (
  * - Returns the path string (not a NixPath object)
  * - Preserves string context if present
  */
-export const coerceToPath = (value: NixValue, outContext?: NixStringContext): string => {
+export const coerceToPath = (value: NixValue, outContext: NixStringContext): string => {
   const forced = force(value);
 
   if (isPath(forced)) {
     return forced.value;
   }
-  if (isAttrs(forced) && Object.hasOwn(forced, "__toString")) {
-    const toStringFunc = forceFunction(forced.__toString);
+  if (isAttrs(forced) && forced.has("__toString")) {
+    const toStringFunc = forceFunction(forced.get("__toString") as NixValue);
     return coerceToPath(toStringFunc(forced), outContext);
   }
 
@@ -318,3 +288,84 @@ export const coerceToPath = (value: NixValue, outContext?: NixStringContext): st
 export const toStringFunc = (value: NixValue): NixString => {
   return coerceToStringWithContext(value, StringCoercionMode.ToString, false);
 };
+
+export type JsonValue = number | boolean | string | null | { [key: string]: JsonValue } | Array<JsonValue>;
+export const nixValueToJson = (
+  value: NixValue,
+  strict: boolean,
+  outContext: NixStringContext,
+  copyToStore: boolean,
+  seen: Set<NixValue> = new Set(),
+): JsonValue => {
+  const v = strict ? force(value) : value;
+
+  if (isThunk(v) || typeof v === "function")
+    throw new Error(`cannot convert ${isThunk(v) ? "thunk" : "lambda"} to JSON`);
+  if (v === null) return null;
+  if (typeof v === "bigint") {
+    const num = Number(v);
+    if (v > Number.MAX_SAFE_INTEGER || v < Number.MIN_SAFE_INTEGER) {
+      console.warn(`integer ${v} exceeds safe range, precision may be lost`);
+    }
+    return num;
+  }
+  if (typeof v === "number") return v;
+  if (typeof v === "boolean") return v;
+  if (typeof v === "string") return v;
+  if (v instanceof StringWithContext) {
+    for (const elem of v.context) {
+      outContext.add(elem);
+    }
+    return v.value;
+  }
+  if (v instanceof NixPath) {
+    if (copyToStore) {
+      const storePath = Deno.core.ops.op_copy_path_to_store(v.value);
+      outContext.add(storePath);
+      return storePath;
+    } else {
+      return v.value;
+    }
+  }
+
+  // FIXME: is this check necessary?
+  // if (seen.has(v)) {
+  //   throw new Error("cycle detected in toJSON");
+  // } else {
+  //   seen.add(v)
+  // }
+
+  if (Array.isArray(v)) {
+    return v.map((item) => nixValueToJson(item, strict, outContext, copyToStore, seen));
+  }
+
+  if (v instanceof Map) {
+    if (v.has("__toString") && typeof force(v.get("__toString") as NixValue) === "function") {
+      const toStringMethod = force(v.get("__toString") as NixValue) as (self: typeof v) => NixValue;
+      const result = force(toStringMethod(v));
+      if (typeof result === "string") {
+        return result;
+      }
+      if (isStringWithContext(result)) {
+        for (const elem of result.context) {
+          outContext.add(elem);
+        }
+        return result.value;
+      }
+      return nixValueToJson(result, strict, outContext, copyToStore, seen);
+    }
+
+    if (v.has("outPath")) {
+      return nixValueToJson(v.get("outPath") as NixValue, strict, outContext, copyToStore, seen);
+    }
+
+    const result: { [key: string]: JsonValue } = {};
+    const keys = Array.from(v.keys()).sort();
+    for (const key of keys) {
+      result[key] = nixValueToJson(v.get(key) as NixValue, strict, outContext, copyToStore, seen);
+    }
+    return result;
+  }
+
+  throw new Error(`cannot convert ${typeof v} to JSON`);
+};

nix-js/runtime-ts/src/builtins/derivation.ts

@@ -1,38 +1,125 @@
-import type { NixValue, NixAttrs } from "../types";
-import { forceStringValue, forceList } from "../type-assert";
-import { force, createThunk } from "../thunk";
-import { type DerivationData, type OutputInfo, generateAterm } from "../derivation-helpers";
-import { coerceToString, StringCoercionMode } from "./conversion";
 import {
-  type NixStringContext,
-  extractInputDrvsAndSrcs,
-  isStringWithContext,
-  mkStringWithContext,
-  addDrvDeepContext,
   addBuiltContext,
+  addDrvDeepContext,
+  mkStringWithContext,
+  type NixStringContext,
 } from "../string-context";
-import { nixValueToJson } from "../conversion";
-import { isNixPath } from "../types";
+import { force } from "../thunk";
+import { forceAttrs, forceList, forceStringNoCtx, forceStringValue } from "../type-assert";
+import type { NixAttrs, NixValue } from "../types";
+import { coerceToString, type JsonValue, nixValueToJson, StringCoercionMode } from "./conversion";
 
-const forceAttrs = (value: NixValue): NixAttrs => {
-  const forced = force(value);
-  if (
-    typeof forced !== "object" ||
-    forced === null ||
-    Array.isArray(forced) ||
-    isStringWithContext(forced) ||
-    isNixPath(forced)
-  ) {
-    throw new TypeError(`Expected attribute set for derivation, got ${typeof forced}`);
+export interface OutputInfo {
+  path: string;
+  hashAlgo: string;
+  hash: string;
 }
-  return forced;
+
+export interface DerivationData {
+  name: string;
+  outputs: Map<string, OutputInfo>;
+  inputDrvs: Map<string, Set<string>>;
+  inputSrcs: Set<string>;
+  platform: string;
+  builder: string;
+  args: string[];
+  env: Map<string, string>;
+}
+
+export const escapeString = (s: string): string => {
+  let result = "";
+  for (const char of s) {
+    switch (char) {
+      case '"':
+        result += '\\"';
+        break;
+      case "\\":
+        result += "\\\\";
+        break;
+      case "\n":
+        result += "\\n";
+        break;
+      case "\r":
+        result += "\\r";
+        break;
+      case "\t":
+        result += "\\t";
+        break;
+      default:
+        result += char;
+    }
+  }
+  return `"${result}"`;
 };
 
+const quoteString = (s: string): string => `"${s}"`;
+
+const cmpByKey = <T>(a: [string, T], b: [string, T]): number => (a[0] < b[0] ? -1 : a[0] > b[0] ? 1 : 0);
+
+export const generateAterm = (drv: DerivationData): string => {
+  const outputEntries: string[] = [];
+  const sortedOutputs = Array.from(drv.outputs.entries()).sort(cmpByKey);
+  for (const [name, info] of sortedOutputs) {
+    outputEntries.push(
+      `(${quoteString(name)},${quoteString(info.path)},${quoteString(info.hashAlgo)},${quoteString(info.hash)})`,
+    );
+  }
+  const outputs = outputEntries.join(",");
+
+  const inputDrvEntries: string[] = [];
+  const sortedInputDrvs = Array.from(drv.inputDrvs.entries()).sort(cmpByKey);
+  for (const [drvPath, outputs] of sortedInputDrvs) {
+    const sortedOuts = Array.from(outputs).sort();
+    const outList = `[${sortedOuts.map(quoteString).join(",")}]`;
+    inputDrvEntries.push(`(${quoteString(drvPath)},${outList})`);
+  }
+  const inputDrvs = inputDrvEntries.join(",");
+
+  const sortedInputSrcs = Array.from(drv.inputSrcs).sort();
+  const inputSrcs = sortedInputSrcs.map(quoteString).join(",");
+
+  const args = drv.args.map(escapeString).join(",");
+  const envs = Array.from(drv.env.entries())
+    .sort(cmpByKey)
+    .map(([k, v]) => `(${escapeString(k)},${escapeString(v)})`);
+
+  return `Derive([${outputs}],[${inputDrvs}],[${inputSrcs}],${quoteString(drv.platform)},${escapeString(drv.builder)},[${args}],[${envs}])`;
+};
+
+export const generateAtermModulo = (drv: DerivationData, inputDrvHashes: Map<string, string>): string => {
+  const outputEntries: string[] = [];
+  const sortedOutputs = Array.from(drv.outputs.entries()).sort(cmpByKey);
+  for (const [name, info] of sortedOutputs) {
+    outputEntries.push(
+      `(${quoteString(name)},${quoteString(info.path)},${quoteString(info.hashAlgo)},${quoteString(info.hash)})`,
+    );
+  }
+  const outputs = outputEntries.join(",");
+
+  const inputDrvEntries: string[] = [];
+  const sortedInputDrvHashes = Array.from(inputDrvHashes.entries()).sort(cmpByKey);
+  for (const [drvHash, outputs] of sortedInputDrvHashes) {
+    const sortedOuts = outputs.split(",").sort();
+    const outList = `[${sortedOuts.map(quoteString).join(",")}]`;
+    inputDrvEntries.push(`(${quoteString(drvHash)},${outList})`);
+  }
+  const inputDrvs = inputDrvEntries.join(",");
+
+  const sortedInputSrcs = Array.from(drv.inputSrcs).sort();
+  const inputSrcs = sortedInputSrcs.map(quoteString).join(",");
+
+  const args = drv.args.map(escapeString).join(",");
+  const envs = Array.from(drv.env.entries())
+    .sort(cmpByKey)
+    .map(([k, v]) => `(${escapeString(k)},${escapeString(v)})`);
+
+  return `Derive([${outputs}],[${inputDrvs}],[${inputSrcs}],${quoteString(drv.platform)},${escapeString(drv.builder)},[${args}],[${envs}])`;
+};
 const validateName = (attrs: NixAttrs): string => {
-  if (!("name" in attrs)) {
+  if (!attrs.has("name")) {
     throw new Error("derivation: missing required attribute 'name'");
   }
-  const name = forceStringValue(attrs.name);
+  const name = forceStringValue(attrs.get("name") as NixValue);
   if (!name) {
     throw new Error("derivation: 'name' cannot be empty");
   }
@@ -43,26 +130,20 @@ const validateName = (attrs: NixAttrs): string => {
 };
 
 const validateBuilder = (attrs: NixAttrs, outContext: NixStringContext): string => {
-  if (!("builder" in attrs)) {
+  if (!attrs.has("builder")) {
     throw new Error("derivation: missing required attribute 'builder'");
   }
-  return coerceToString(attrs.builder, StringCoercionMode.ToString, false, outContext);
+  return coerceToString(attrs.get("builder") as NixValue, StringCoercionMode.ToString, true, outContext);
 };
 
 const validateSystem = (attrs: NixAttrs): string => {
-  if (!("system" in attrs)) {
+  if (!attrs.has("system")) {
     throw new Error("derivation: missing required attribute 'system'");
   }
-  return forceStringValue(attrs.system);
+  return forceStringValue(attrs.get("system") as NixValue);
 };
 
-const extractOutputs = (attrs: NixAttrs): string[] => {
-  if (!("outputs" in attrs)) {
-    return ["out"];
-  }
-  const outputsList = forceList(attrs.outputs);
-  const outputs = outputsList.map((o) => forceStringValue(o));
-
+const validateOutputs = (outputs: string[]): void => {
   if (outputs.length === 0) {
     throw new Error("derivation: outputs list cannot be empty");
   }
@@ -78,16 +159,59 @@ const extractOutputs = (attrs: NixAttrs): string[] => {
     }
     seen.add(output);
   }
+};
 
+const extractOutputs = (attrs: NixAttrs, structuredAttrs: boolean): string[] => {
+  if (!attrs.has("outputs")) {
+    return ["out"];
+  }
+
+  let outputs: string[];
+  if (structuredAttrs) {
+    const outputsList = forceList(attrs.get("outputs") as NixValue);
+    outputs = outputsList.map((o) => forceStringValue(o));
+  } else {
+    const outputsStr = coerceToString(
+      attrs.get("outputs") as NixValue,
+      StringCoercionMode.ToString,
+      false,
+      new Set(),
+    );
+    outputs = outputsStr
+      .trim()
+      .split(/\s+/)
+      .filter((s) => s.length > 0);
+  }
+
+  validateOutputs(outputs);
   return outputs;
 };
 
 const extractArgs = (attrs: NixAttrs, outContext: NixStringContext): string[] => {
-  if (!("args" in attrs)) {
+  if (!attrs.has("args")) {
     return [];
   }
-  const argsList = forceList(attrs.args);
-  return argsList.map((a) => coerceToString(a, StringCoercionMode.ToString, false, outContext));
+  const argsList = forceList(attrs.get("args") as NixValue);
+  return argsList.map((a) => coerceToString(a, StringCoercionMode.ToString, true, outContext));
+};
+
+const structuredAttrsExcludedKeys = new Set([
+  "__structuredAttrs",
+  "__ignoreNulls",
+  "__contentAddressed",
+  "__impure",
+  "args",
+]);
+
+const specialAttrs = new Set(["args", "__ignoreNulls", "__contentAddressed", "__impure"]);
+
+const sortedJsonStringify = (obj: Record<string, JsonValue>): string => {
+  const sortedKeys = Object.keys(obj).sort();
+  const sortedObj: Record<string, JsonValue> = {};
+  for (const key of sortedKeys) {
+    sortedObj[key] = obj[key];
+  }
+  return JSON.stringify(sortedObj);
 };
 
 const extractEnv = (
@@ -97,83 +221,71 @@ const extractEnv = (
   outContext: NixStringContext,
   drvName: string,
 ): Map<string, string> => {
-  const specialAttrs = new Set([
-    "name",
-    "builder",
-    "system",
-    "args",
-    "outputs",
-    "__structuredAttrs",
-    "__ignoreNulls",
-    "__contentAddressed",
-    "impure",
-  ]);
-
   const env = new Map<string, string>();
 
   if (structuredAttrs) {
-    const jsonAttrs: Record<string, any> = {};
-    for (const [key, value] of Object.entries(attrs)) {
-      if (!specialAttrs.has(key)) {
+    const jsonAttrs: Record<string, JsonValue> = {};
+    for (const [key, value] of attrs) {
+      if (!structuredAttrsExcludedKeys.has(key)) {
         const forcedValue = force(value);
         if (ignoreNulls && forcedValue === null) {
           continue;
         }
-        jsonAttrs[key] = nixValueToJson(value, new Set(), outContext);
+        jsonAttrs[key] = nixValueToJson(value, true, outContext, true);
       }
 
       if (key === "allowedReferences") {
         console.warn(
           `In a derivation named '${drvName}', 'structuredAttrs' disables the effect of ` +
             `the derivation attribute 'allowedReferences'; use ` +
-          `'outputChecks.<output>.allowedReferences' instead`
+            `'outputChecks.<output>.allowedReferences' instead`,
         );
       }
       if (key === "allowedRequisites") {
         console.warn(
           `In a derivation named '${drvName}', 'structuredAttrs' disables the effect of ` +
             `the derivation attribute 'allowedRequisites'; use ` +
-          `'outputChecks.<output>.allowedRequisites' instead`
+            `'outputChecks.<output>.allowedRequisites' instead`,
         );
       }
       if (key === "disallowedReferences") {
         console.warn(
           `In a derivation named '${drvName}', 'structuredAttrs' disables the effect of ` +
             `the derivation attribute 'disallowedReferences'; use ` +
-          `'outputChecks.<output>.disallowedReferences' instead`
+            `'outputChecks.<output>.disallowedReferences' instead`,
         );
       }
       if (key === "disallowedRequisites") {
         console.warn(
           `In a derivation named '${drvName}', 'structuredAttrs' disables the effect of ` +
             `the derivation attribute 'disallowedRequisites'; use ` +
-          `'outputChecks.<output>.disallowedRequisites' instead`
+            `'outputChecks.<output>.disallowedRequisites' instead`,
         );
       }
       if (key === "maxSize") {
         console.warn(
           `In a derivation named '${drvName}', 'structuredAttrs' disables the effect of ` +
             `the derivation attribute 'maxSize'; use ` +
-          `'outputChecks.<output>.maxSize' instead`
+            `'outputChecks.<output>.maxSize' instead`,
         );
       }
       if (key === "maxClosureSize") {
         console.warn(
           `In a derivation named '${drvName}', 'structuredAttrs' disables the effect of ` +
             `the derivation attribute 'maxClosureSize'; use ` +
-          `'outputChecks.<output>.maxClosureSize' instead`
+            `'outputChecks.<output>.maxClosureSize' instead`,
         );
       }
     }
-    env.set("__json", JSON.stringify(jsonAttrs));
+    env.set("__json", sortedJsonStringify(jsonAttrs));
   } else {
-    for (const [key, value] of Object.entries(attrs)) {
+    for (const [key, value] of attrs) {
       if (!specialAttrs.has(key)) {
-        const forcedValue = force(value);
+        const forcedValue = force(value as NixValue);
         if (ignoreNulls && forcedValue === null) {
           continue;
         }
-        env.set(key, coerceToString(value, StringCoercionMode.ToString, false, outContext));
+        env.set(key, coerceToString(value as NixValue, StringCoercionMode.ToString, true, outContext));
       }
     }
   }
@@ -187,20 +299,40 @@ interface FixedOutputInfo {
   hashMode: string;
 }
 
-const extractFixedOutputInfo = (attrs: NixAttrs): FixedOutputInfo | null => {
-  if (!("outputHash" in attrs)) {
+const extractFixedOutputInfo = (attrs: NixAttrs, ignoreNulls: boolean): FixedOutputInfo | null => {
+  if (!attrs.has("outputHash")) {
     return null;
   }
 
-  const hash = forceStringValue(attrs.outputHash);
-  const hashAlgo = "outputHashAlgo" in attrs ? forceStringValue(attrs.outputHashAlgo) : "sha256";
-  const hashMode = "outputHashMode" in attrs ? forceStringValue(attrs.outputHashMode) : "flat";
+  const hashValue = force(attrs.get("outputHash") as NixValue);
+  if (ignoreNulls && hashValue === null) {
+    return null;
+  }
+  const hashRaw = forceStringNoCtx(hashValue);
+
+  let hashAlgo = null;
+  if (attrs.has("outputHashAlgo")) {
+    const algoValue = force(attrs.get("outputHashAlgo") as NixValue);
+    if (!(ignoreNulls && algoValue === null)) {
+      hashAlgo = forceStringNoCtx(algoValue);
+    }
+  }
+
+  let hashMode = "flat";
+  if (attrs.has("outputHashMode")) {
+    const modeValue = force(attrs.get("outputHashMode") as NixValue);
+    if (!(ignoreNulls && modeValue === null)) {
+      hashMode = forceStringValue(modeValue);
+    }
+  }
 
   if (hashMode !== "flat" && hashMode !== "recursive") {
     throw new Error(`derivation: invalid outputHashMode '${hashMode}' (must be 'flat' or 'recursive')`);
   }
 
-  return { hash, hashAlgo, hashMode };
+  const parsed = Deno.core.ops.op_parse_hash(hashRaw, hashAlgo);
+
+  return { hash: parsed.hex, hashAlgo: parsed.algo, hashMode };
 };
 
 const validateFixedOutputConstraints = (fixedOutput: FixedOutputInfo | null, outputs: string[]) => {
@@ -217,200 +349,60 @@ export const derivationStrict = (args: NixValue): NixAttrs => {
   const builder = validateBuilder(attrs, collectedContext);
   const platform = validateSystem(attrs);
 
-  const outputs = extractOutputs(attrs);
-  const fixedOutputInfo = extractFixedOutputInfo(attrs);
+  const structuredAttrs = attrs.has("__structuredAttrs")
+    ? force(attrs.get("__structuredAttrs") as NixValue) === true
+    : false;
+  const ignoreNulls = attrs.has("__ignoreNulls")
+    ? force(attrs.get("__ignoreNulls") as NixValue) === true
+    : false;
+
+  const outputs = extractOutputs(attrs, structuredAttrs);
+  const fixedOutputInfo = extractFixedOutputInfo(attrs, ignoreNulls);
   validateFixedOutputConstraints(fixedOutputInfo, outputs);
 
-  const structuredAttrs = "__structuredAttrs" in attrs ? force(attrs.__structuredAttrs) === true : false;
-
-  const ignoreNulls = "__ignoreNulls" in attrs ? force(attrs.__ignoreNulls) === true : false;
-
-  if ("__contentAddressed" in attrs && force(attrs.__contentAddressed) === true) {
+  if (attrs.has("__contentAddressed") && force(attrs.get("__contentAddressed") as NixValue) === true) {
     throw new Error("ca derivations are not supported");
   }
 
-  if ("impure" in attrs && force(attrs.impure) === true) {
+  if (attrs.has("__impure") && force(attrs.get("__impure") as NixValue) === true) {
     throw new Error("impure derivations are not supported");
   }
 
   const drvArgs = extractArgs(attrs, collectedContext);
   const env = extractEnv(attrs, structuredAttrs, ignoreNulls, collectedContext, drvName);
 
-  env.set("name", drvName);
-  env.set("builder", builder);
-  env.set("system", platform);
-  if (outputs.length > 1 || outputs[0] !== "out") {
-    env.set("outputs", outputs.join(" "));
-  }
+  const envEntries: [string, string][] = Array.from(env.entries());
+  const contextArray: string[] = Array.from(collectedContext);
 
-  const { inputDrvs, inputSrcs } = extractInputDrvsAndSrcs(collectedContext);
-
-  let outputInfos: Map<string, OutputInfo>;
-  let drvPath: string;
-
-  if (fixedOutputInfo) {
-    const pathName = Deno.core.ops.op_output_path_name(drvName, "out");
-    const outPath = Deno.core.ops.op_make_fixed_output_path(
-      fixedOutputInfo.hashAlgo,
-      fixedOutputInfo.hash,
-      fixedOutputInfo.hashMode,
-      pathName,
+  const rustResult: {
+    drvPath: string;
+    outputs: [string, string][];
+  } = Deno.core.ops.op_finalize_derivation(
+    drvName,
+    builder,
+    platform,
+    outputs,
+    drvArgs,
+    envEntries,
+    contextArray,
+    fixedOutputInfo,
   );
 
-    const hashAlgoPrefix = fixedOutputInfo.hashMode === "recursive" ? "r:" : "";
-    outputInfos = new Map([
-      [
-        "out",
-        {
-          path: outPath,
-          hashAlgo: hashAlgoPrefix + fixedOutputInfo.hashAlgo,
-          hash: fixedOutputInfo.hash,
-        },
-      ],
-    ]);
-    env.set("out", outPath);
-
-    const finalDrv: DerivationData = {
-      name: drvName,
-      outputs: outputInfos,
-      inputDrvs,
-      inputSrcs,
-      platform,
-      builder,
-      args: drvArgs,
-      env,
-    };
-    const finalAterm = generateAterm(finalDrv);
-    const finalDrvHash = Deno.core.ops.op_sha256_hex(finalAterm);
-    drvPath = Deno.core.ops.op_make_store_path("text", finalDrvHash, `${drvName}.drv`);
-  } else {
-    const maskedOutputs = new Map<string, OutputInfo>(
-      outputs.map((o) => [
-        o,
-        {
-          path: "",
-          hashAlgo: "",
-          hash: "",
-        },
-      ]),
-    );
-    const maskedEnv = new Map(env);
-    for (const output of outputs) {
-      maskedEnv.set(output, "");
-    }
-
-    const maskedDrv: DerivationData = {
-      name: drvName,
-      outputs: maskedOutputs,
-      inputDrvs,
-      inputSrcs,
-      platform,
-      builder,
-      args: drvArgs,
-      env: maskedEnv,
-    };
-
-    const maskedAterm = generateAterm(maskedDrv);
-    const drvModuloHash = Deno.core.ops.op_sha256_hex(maskedAterm);
-
-    outputInfos = new Map<string, OutputInfo>();
-    for (const outputName of outputs) {
-      const pathName = Deno.core.ops.op_output_path_name(drvName, outputName);
-      const outPath = Deno.core.ops.op_make_store_path(`output:${outputName}`, drvModuloHash, pathName);
-      outputInfos.set(outputName, {
-        path: outPath,
-        hashAlgo: "",
-        hash: "",
-      });
-      env.set(outputName, outPath);
-    }
-
-    const finalDrv: DerivationData = {
-      ...maskedDrv,
-      outputs: outputInfos,
-      env,
-    };
-    const finalAterm = generateAterm(finalDrv);
-    const finalDrvHash = Deno.core.ops.op_sha256_hex(finalAterm);
-
-    drvPath = Deno.core.ops.op_make_store_path("text", finalDrvHash, `${drvName}.drv`);
-  }
-
-  const result: NixAttrs = {};
+  const result: NixAttrs = new Map();
 
   const drvPathContext = new Set<string>();
-  addDrvDeepContext(drvPathContext, drvPath);
-  result.drvPath = mkStringWithContext(drvPath, drvPathContext);
+  addDrvDeepContext(drvPathContext, rustResult.drvPath);
+  result.set("drvPath", mkStringWithContext(rustResult.drvPath, drvPathContext));
 
-  for (const [outputName, outputInfo] of outputInfos.entries()) {
+  for (const [outputName, outputPath] of rustResult.outputs) {
     const outputContext = new Set<string>();
-    addBuiltContext(outputContext, drvPath, outputName);
-    result[outputName] = mkStringWithContext(outputInfo.path, outputContext);
+    addBuiltContext(outputContext, rustResult.drvPath, outputName);
+    result.set(outputName, mkStringWithContext(outputPath, outputContext));
   }
 
   return result;
 };
 
-const specialAttrs = new Set([
-  "name",
-  "builder",
-  "system",
-  "args",
-  "outputs",
-  "__structuredAttrs",
-  "__ignoreNulls",
-  "__contentAddressed",
-  "impure",
-]);
-
-export const derivation = (args: NixValue): NixAttrs => {
-  const attrs = forceAttrs(args);
-
-  const outputs: string[] = extractOutputs(attrs);
-
-  const strictThunk = createThunk(() => derivationStrict(args), "derivationStrict");
-
-  const commonAttrs: NixAttrs = { ...attrs };
-
-  const outputToAttrListElement = (outputName: string): { name: string; value: NixAttrs } => {
-    const value: NixAttrs = {
-      ...commonAttrs,
-      outPath: createThunk(() => (force(strictThunk) as NixAttrs)[outputName], `outPath_${outputName}`),
-      drvPath: createThunk(() => (force(strictThunk) as NixAttrs).drvPath, "drvPath"),
-      type: "derivation",
-      outputName,
+export const derivationStub = (_: NixValue): NixAttrs => {
+  throw new Error("unreachable: stub derivation implementation called");
 };
-    return { name: outputName, value };
-  };
-
-  const outputsList = outputs.map(outputToAttrListElement);
-
-  for (const { name: outputName, value } of outputsList) {
-    commonAttrs[outputName] = createThunk(
-      () => outputsList.find((o) => o.name === outputName)!.value,
-      `output_${outputName}`,
-    );
-  }
-  commonAttrs.all = createThunk(
-    () => outputsList.map((o) => o.value),
-    "all_outputs",
-  );
-  commonAttrs.drvAttrs = attrs;
-
-  for (const { value: outputObj } of outputsList) {
-    for (const { name: outputName } of outputsList) {
-      outputObj[outputName] = createThunk(
-        () => outputsList.find((o) => o.name === outputName)!.value,
-        `output_${outputName}`,
-      );
-    }
-    outputObj.all = createThunk(
-      () => outputsList.map((o) => o.value),
-      "all_outputs",
-    );
-    outputObj.drvAttrs = attrs;
-  }
-
-  return outputsList[0].value;
-};
-

nix-js/runtime-ts/src/builtins/flake.ts

@@ -0,0 +1,17 @@
+import type { NixValue } from "../types";
+
+export const getFlake = (_attrs: NixValue): never => {
+  throw new Error("Not implemented: getFlake");
+};
+
+export const parseFlakeName = (_s: NixValue): never => {
+  throw new Error("Not implemented: parseFlakeName");
+};
+
+export const parseFlakeRef = (_s: NixValue): never => {
+  throw new Error("Not implemented: parseFlakeRef");
+};
+
+export const flakeRefToString = (_attrs: NixValue): never => {
+  throw new Error("Not implemented: flakeRefToString");
+};

nix-js/runtime-ts/src/builtins/functional.ts

@@ -1,10 +1,8 @@
-/**
- * Functional programming builtin functions
- */
-
-import { CatchableError, HAS_CONTEXT, type NixValue } from "../types";
+import { printValue } from "../print";
 import { force } from "../thunk";
+import { CatchableError, type NixValue } from "../types";
 import { coerceToString, StringCoercionMode } from "./conversion";
+import { isAttrs } from "./type-check";
 
 export const seq =
   (e1: NixValue) =>
@@ -16,16 +14,25 @@ export const seq =
 export const deepSeq =
   (e1: NixValue) =>
   (e2: NixValue): NixValue => {
-    const forced = force(e1);
+    const seen: Set<NixValue> = new Set();
+    const recurse = (e: NixValue) => {
+      if (!seen.has(e)) {
+        seen.add(e);
+      } else {
+        return;
+      }
+      const forced = force(e);
       if (Array.isArray(forced)) {
         for (const val of forced) {
-        deepSeq(val);
+          recurse(val);
         }
-    } else if (typeof forced === "object" && forced !== null && !(HAS_CONTEXT in forced)) {
-      for (const [_, val] of Object.entries(forced)) {
-        deepSeq(val);
+      } else if (isAttrs(forced)) {
+        for (const [_, val] of forced.entries()) {
+          recurse(val);
         }
       }
+    };
+    recurse(e1);
     return e2;
   };
 
@@ -34,13 +41,13 @@ export const abort = (s: NixValue): never => {
 };
 
 export const throwFunc = (s: NixValue): never => {
-  throw new CatchableError(coerceToString(s, StringCoercionMode.Base));
+  throw new CatchableError(coerceToString(s, StringCoercionMode.Base, false, new Set()));
 };
 
 export const trace =
   (e1: NixValue) =>
   (e2: NixValue): NixValue => {
-    console.log(`trace: ${coerceToString(e1, StringCoercionMode.Base)}`);
+    console.error(`trace: ${printValue(force(e1))}`);
     return e2;
   };
 

nix-js/runtime-ts/src/builtins/hash.ts

@@ -0,0 +1,34 @@
+import { select } from "../helpers";
+import { forceAttrs, forceStringNoCtx, forceStringValue } from "../type-assert";
+import type { NixValue } from "../types";
+import { realisePath } from "./io";
+
+export const hashFile =
+  (type: NixValue) =>
+  (p: NixValue): string => {
+    const algo = forceStringNoCtx(type);
+    const pathStr = realisePath(p);
+    return Deno.core.ops.op_hash_file(algo, pathStr);
+  };
+
+export const hashString =
+  (type: NixValue) =>
+  (s: NixValue): string => {
+    const algo = forceStringNoCtx(type);
+    const data = forceStringValue(s);
+    return Deno.core.ops.op_hash_string(algo, data);
+  };
+
+export const convertHash = (args: NixValue): string => {
+  const attrs = forceAttrs(args);
+  const hash = forceStringNoCtx(select(attrs, ["hash"]));
+
+  let hashAlgo: string | null = null;
+  if (attrs.has("hashAlgo")) {
+    hashAlgo = forceStringNoCtx(select(attrs, ["hashAlgo"]));
+  }
+
+  const toHashFormat = forceStringNoCtx(select(attrs, ["toHashFormat"]));
+
+  return Deno.core.ops.op_convert_hash(hash, hashAlgo, toHashFormat);
+};

nix-js/runtime-ts/src/builtins/index.ts

@@ -1,85 +1,54 @@
-/**
- * Main builtins export
- * Combines all builtin function categories into the global `builtins` object
- */
-
-// Import all builtin categories
+import { createThunk, force } from "../thunk";
+import type { NixAttrs, NixFunction, NixValue } from "../types";
 import * as arithmetic from "./arithmetic";
-import * as math from "./math";
-import * as typeCheck from "./type-check";
-import * as list from "./list";
 import * as attrs from "./attrs";
-import * as string from "./string";
-import * as pathOps from "./path";
-import * as functional from "./functional";
-import * as io from "./io";
 import * as conversion from "./conversion";
-import * as misc from "./misc";
 import * as derivation from "./derivation";
+import * as flake from "./flake";
+import * as functional from "./functional";
+import * as hash from "./hash";
+import * as io from "./io";
+import * as list from "./list";
+import * as math from "./math";
+import * as misc from "./misc";
+import * as pathOps from "./path";
+import * as string from "./string";
+import * as typeCheck from "./type-check";
 
-import type { NixValue } from "../types";
-import { createThunk, force, isThunk } from "../thunk";
-import { getTos } from "../helpers";
-
-/**
- * Symbol used to mark functions as primops (primitive operations)
- * This is similar to IS_THUNK but for builtin functions
- */
 export const PRIMOP_METADATA = Symbol("primop_metadata");
 
-/**
- * Metadata interface for primop functions
- */
 export interface PrimopMetadata {
-  /** The name of the primop (e.g., "add", "map") */
   name: string;
-  /** Total arity of the function (number of arguments it expects) */
   arity: number;
-  /** Number of arguments already applied (for partial applications) */
   applied: number;
 }
 
-/**
- * Mark a function as a primop with metadata
- * For curried functions, this recursively marks each layer
- *
- * @param func - The function to mark
- * @param name - Name of the primop
- * @param arity - Total number of arguments expected
- * @param applied - Number of arguments already applied (default: 0)
- * @returns The marked function
- */
 export const mkPrimop = (
-  func: (...args: NixValue[]) => NixValue,
+  func: NixFunction,
   name: string,
   arity: number,
   applied: number = 0,
-): Function => {
-  // Mark this function as a primop
-  (func as any)[PRIMOP_METADATA] = {
+): ((...args: NixValue[]) => NixValue) => {
+  func[PRIMOP_METADATA] = {
     name,
     arity,
     applied,
   } satisfies PrimopMetadata;
 
-  // If this is a curried function and not fully applied,
-  // wrap it to mark the next layer too
   if (applied < arity - 1) {
-    const wrappedFunc = ((...args: NixValue[]) => {
-      const result = func(...args);
-      // If result is a function, mark it as the next layer
+    const wrappedFunc: NixFunction = ((arg: NixValue) => {
+      const result = func(arg);
       if (typeof result === "function") {
-        return mkPrimop(result, name, arity, applied + args.length);
+        return mkPrimop(result, name, arity, applied + 1);
       }
       return result;
-    }) as any;
+    });
 
-    // Copy the primop metadata to the wrapper
     wrappedFunc[PRIMOP_METADATA] = {
       name,
       arity,
       applied,
-    } satisfies PrimopMetadata;
+    };
 
     return wrappedFunc;
   }
@@ -87,12 +56,9 @@ export const mkPrimop = (
   return func;
 };
 
-/**
- * Type guard to check if a value is a primop
- * @param value - Value to check
- * @returns true if value is marked as a primop
- */
-export const is_primop = (value: unknown): value is Function & { [PRIMOP_METADATA]: PrimopMetadata } => {
+export const isPrimop = (
+  value: NixValue,
+): value is NixFunction & { [PRIMOP_METADATA]: PrimopMetadata } => {
   return (
     typeof value === "function" &&
     PRIMOP_METADATA in value &&
@@ -101,29 +67,15 @@ export const is_primop = (value: unknown): value is Function & { [PRIMOP_METADAT
   );
 };
 
-/**
- * Get primop metadata from a function
- * @param func - Function to get metadata from
- * @returns Metadata if function is a primop, undefined otherwise
- */
-export const get_primop_metadata = (func: unknown): PrimopMetadata | undefined => {
-  if (is_primop(func)) {
+export const getPrimopMetadata = (func: NixValue): PrimopMetadata | undefined => {
+  if (isPrimop(func)) {
     return func[PRIMOP_METADATA];
   }
   return undefined;
 };
 
-/**
- * The global builtins object
- * Contains 80+ Nix builtin functions plus metadata
- *
- * All functions are curried for Nix semantics:
- * - Single argument functions: (a) => result
- * - Multi-argument functions: (a) => (b) => result
- *
- * All primop functions are marked with PRIMOP_METADATA symbol for runtime introspection
- */
-export const builtins: any = {
+export const builtins: NixAttrs = new Map<string, NixValue>(
+  Object.entries({
     add: mkPrimop(arithmetic.add, "add", 2),
     sub: mkPrimop(arithmetic.sub, "sub", 2),
     mul: mkPrimop(arithmetic.mul, "mul", 2),
@@ -193,7 +145,7 @@ export const builtins: any = {
     warn: mkPrimop(functional.warn, "warn", 2),
     break: mkPrimop(functional.breakFunc, "break", 1),
 
-  derivation: mkPrimop(derivation.derivation, "derivation", 1),
+    derivation: mkPrimop(derivation.derivationStub, "derivation", 1),
     derivationStrict: mkPrimop(derivation.derivationStrict, "derivationStrict", 1),
 
     import: mkPrimop(io.importFunc, "import", 1),
@@ -221,13 +173,19 @@ export const builtins: any = {
     toXML: mkPrimop(conversion.toXML, "toXML", 1),
     toString: mkPrimop(conversion.toStringFunc, "toString", 1),
 
+    hashFile: mkPrimop(hash.hashFile, "hashFile", 2),
+    hashString: mkPrimop(hash.hashString, "hashString", 2),
+    convertHash: mkPrimop(hash.convertHash, "convertHash", 2),
+
+    flakeRefToString: mkPrimop(flake.flakeRefToString, "flakeRefToString", 1),
+    getFlake: mkPrimop(flake.getFlake, "getFlake", 1),
+    parseFlakeName: mkPrimop(flake.parseFlakeName, "parseFlakeName", 1),
+    parseFlakeRef: mkPrimop(flake.parseFlakeRef, "parseFlakeRef", 1),
+
     addErrorContext: mkPrimop(misc.addErrorContext, "addErrorContext", 1),
     appendContext: mkPrimop(misc.appendContext, "appendContext", 1),
     getContext: mkPrimop(misc.getContext, "getContext", 1),
     hasContext: mkPrimop(misc.hasContext, "hasContext", 1),
-  hashFile: mkPrimop(misc.hashFile, "hashFile", 2),
-  hashString: mkPrimop(misc.hashString, "hashString", 2),
-  convertHash: mkPrimop(misc.convertHash, "convertHash", 2),
     unsafeDiscardOutputDependency: mkPrimop(
       misc.unsafeDiscardOutputDependency,
       "unsafeDiscardOutputDependency",
@@ -236,14 +194,10 @@ export const builtins: any = {
     unsafeDiscardStringContext: mkPrimop(misc.unsafeDiscardStringContext, "unsafeDiscardStringContext", 1),
     addDrvOutputDependencies: mkPrimop(misc.addDrvOutputDependencies, "addDrvOutputDependencies", 2),
     compareVersions: mkPrimop(misc.compareVersions, "compareVersions", 2),
-  flakeRefToString: mkPrimop(misc.flakeRefToString, "flakeRefToString", 1),
     functionArgs: mkPrimop(misc.functionArgs, "functionArgs", 1),
     genericClosure: mkPrimop(misc.genericClosure, "genericClosure", 1),
-  getFlake: mkPrimop(misc.getFlake, "getFlake", 1),
     outputOf: mkPrimop(misc.outputOf, "outputOf", 2),
     parseDrvName: mkPrimop(misc.parseDrvName, "parseDrvName", 1),
-  parseFlakeName: mkPrimop(misc.parseFlakeName, "parseFlakeName", 1),
-  parseFlakeRef: mkPrimop(misc.parseFlakeRef, "parseFlakeRef", 1),
     placeholder: mkPrimop(misc.placeholder, "placeholder", 1),
     replaceStrings: mkPrimop(misc.replaceStrings, "replaceStrings", 3),
     splitVersion: mkPrimop(misc.splitVersion, "splitVersion", 1),
@@ -263,10 +217,8 @@ export const builtins: any = {
     langVersion: 6,
     nixPath: [],
     nixVersion: "2.31.2",
-  storeDir: "INVALID_PATH",
-
-  __traceCaller: (e: NixValue) => {
-    console.log(`traceCaller: ${getTos()}`)
-    return e
-  },
-};
+    storeDir: createThunk(() => {
+      throw new Error("stub storeDir evaluated");
+    }),
+  }),
+);

nix-js/runtime-ts/src/builtins/io.ts

@@ -1,44 +1,57 @@
-/**
- * I/O and filesystem builtin functions
- * Implemented via Rust ops exposed through deno_core
- */
-
-import { forceAttrs, forceBool, forceList, forceStringNoCtx, forceStringValue } from "../type-assert";
-import type { NixValue, NixAttrs, NixPath } from "../types";
-import { isNixPath, IS_PATH, CatchableError } from "../types";
-import { force } from "../thunk";
-import { coerceToPath, coerceToString, StringCoercionMode } from "./conversion";
+import { select } from "../helpers";
 import { getPathValue } from "../path";
 import type { NixStringContext, StringWithContext } from "../string-context";
-import { mkStringWithContext } from "../string-context";
-import { isPath } from "./type-check";
+import { addOpaqueContext, decodeContextElem, mkStringWithContext } from "../string-context";
+import { force } from "../thunk";
+import {
+  forceAttrs,
+  forceBool,
+  forceFunction,
+  forceList,
+  forceStringNoCtx,
+  forceStringValue,
+} from "../type-assert";
+import type { NixAttrs, NixString, NixValue } from "../types";
+import { CatchableError, isNixPath, NixPath } from "../types";
+import { coerceToPath, coerceToString, StringCoercionMode } from "./conversion";
+import { baseNameOf } from "./path";
+import { isAttrs, isPath, isString } from "./type-check";
+import { execBytecode, execBytecodeScoped } from "../vm";
 
 const importCache = new Map<string, NixValue>();
 
-export const importFunc = (path: NixValue): NixValue => {
-  const context: NixStringContext = new Set();
-  const pathStr = coerceToPath(path, context);
-
-  // FIXME: Context collected but not yet propagated to build system
-  // This means derivation dependencies from imported paths are not
-  // currently tracked. This will cause issues when:
-  // 1. Importing from derivation outputs: import "${drv}/file.nix"
-  // 2. Building packages that depend on imported configurations
-  if (context.size > 0) {
-    console.warn(
-      `[WARN] import: Path has string context which is not yet fully tracked.
-Dependency tracking for imported derivations may be incomplete.`,
+const realiseContext = (context: NixStringContext): void => {
+  for (const encoded of context) {
+    const elem = decodeContextElem(encoded);
+    if (elem.type === "built") {
+      throw new Error(
+        `cannot build derivation '${elem.drvPath}' during evaluation because import-from-derivation is not supported`,
       );
     }
+  }
+};
+
+export const realisePath = (value: NixValue): string => {
+  const context: NixStringContext = new Set();
+  const pathStr = coerceToPath(value, context);
+
+  if (context.size > 0) {
+    realiseContext(context);
+  }
+
+  return pathStr;
+};
+
+export const importFunc = (path: NixValue): NixValue => {
+  const pathStr = realisePath(path);
 
   const cached = importCache.get(pathStr);
   if (cached !== undefined) {
     return cached;
   }
 
-  // Call Rust op - returns JS code string
-  const code = Deno.core.ops.op_import(pathStr);
-  const result = Function(`return (${code})`)();
+  const [code, currentDir] = Deno.core.ops.op_import(pathStr);
+  const result = execBytecode(code, currentDir);
 
   importCache.set(pathStr, result);
   return result;
@@ -46,8 +59,14 @@ Dependency tracking for imported derivations may be incomplete.`,
 
 export const scopedImport =
   (scope: NixValue) =>
-  (path: NixValue): never => {
-    throw new Error("Not implemented: scopedImport");
+  (path: NixValue): NixValue => {
+    const scopeAttrs = forceAttrs(scope);
+    const scopeKeys = Array.from(scopeAttrs.keys());
+
+    const pathStr = realisePath(path);
+
+    const [code, currentDir] = Deno.core.ops.op_scoped_import(pathStr, scopeKeys);
+    return execBytecodeScoped(code, currentDir, scopeAttrs);
   };
 
 export const storePath = (pathArg: NixValue): StringWithContext => {
@@ -60,38 +79,29 @@ export const storePath = (pathArg: NixValue): StringWithContext => {
   return mkStringWithContext(validatedPath, context);
 };
 
-export const fetchClosure = (args: NixValue): never => {
+export const fetchClosure = (_args: NixValue): never => {
   throw new Error("Not implemented: fetchClosure");
 };
 
-interface FetchUrlResult {
-  store_path: string;
+export interface FetchUrlResult {
+  storePath: string;
   hash: string;
 }
 
-interface FetchTarballResult {
-  store_path: string;
-  hash: string;
-  nar_hash: string;
+export interface FetchTarballResult {
+  storePath: string;
+  narHash: string;
 }
 
-interface FetchGitResult {
-  out_path: string;
+export interface FetchGitResult {
+  outPath: string;
   rev: string;
-  short_rev: string;
-  rev_count: number;
-  last_modified: number;
-  last_modified_date: string;
+  shortRev: string;
+  revCount: number;
+  lastModified: number;
+  lastModifiedDate: string;
   submodules: boolean;
-  nar_hash: string | null;
-}
-
-interface FetchHgResult {
-  out_path: string;
-  branch: string;
-  rev: string;
-  short_rev: string;
-  rev_count: number;
+  narHash: string | null;
 }
 
 const normalizeUrlInput = (
@@ -102,39 +112,39 @@ const normalizeUrlInput = (
     return { url: forced };
   }
   const attrs = forceAttrs(args);
-  const url = forceStringValue(attrs.url);
-  const hash =
-    "sha256" in attrs
-      ? forceStringValue(attrs.sha256)
-      : "hash" in attrs
-        ? forceStringValue(attrs.hash)
+  const url = forceStringValue(select(attrs, ["url"]));
+  const hash = attrs.has("sha256")
+    ? forceStringValue(attrs.get("sha256") as NixValue)
+    : attrs.has("hash")
+      ? forceStringValue(attrs.get("hash") as NixValue)
       : undefined;
-  const name = "name" in attrs ? forceStringValue(attrs.name) : undefined;
-  const executable = "executable" in attrs ? forceBool(attrs.executable) : false;
+  const name = attrs.has("name") ? forceStringValue(attrs.get("name") as NixValue) : undefined;
+  const executable = attrs.has("executable") ? forceBool(attrs.get("executable") as NixValue) : false;
   return { url, hash, name, executable };
 };
 
-const normalizeTarballInput = (
-  args: NixValue,
-): { url: string; hash?: string; narHash?: string; name?: string } => {
+const normalizeTarballInput = (args: NixValue): { url: string; sha256?: string; name?: string } => {
   const forced = force(args);
-  if (typeof forced === "string") {
-    return { url: forced };
+  if (isAttrs(forced)) {
+    const url = resolvePseudoUrl(forceStringNoCtx(select(forced, ["url"])));
+    const sha256 = forced.has("sha256") ? forceStringNoCtx(forced.get("sha256") as NixValue) : undefined;
+    const nameRaw = forced.has("name") ? forceStringNoCtx(forced.get("name") as NixValue) : undefined;
+    const name = nameRaw === "" ? (baseNameOf(nameRaw) as string) : nameRaw;
+    return { url, sha256, name };
+  } else {
+    return { url: forceStringNoCtx(forced) };
   }
-  const attrs = forceAttrs(args);
-  const url = forceStringValue(attrs.url);
-  const hash = "hash" in attrs ? forceStringValue(attrs.hash) : undefined;
-  const narHash =
-    "narHash" in attrs
-      ? forceStringValue(attrs.narHash)
-      : "sha256" in attrs
-        ? forceStringValue(attrs.sha256)
-        : undefined;
-  const name = "name" in attrs ? forceStringValue(attrs.name) : undefined;
-  return { url, hash, narHash, name };
 };
 
-export const fetchurl = (args: NixValue): string => {
+const resolvePseudoUrl = (url: string) => {
+  if (url.startsWith("channel:")) {
+    return `https://channels.nixos.org/${url.substring(8)}/nixexprs.tar.xz`;
+  } else {
+    return url;
+  }
+};
+
+export const fetchurl = (args: NixValue): NixString => {
   const { url, hash, name, executable } = normalizeUrlInput(args);
   const result: FetchUrlResult = Deno.core.ops.op_fetch_url(
     url,
@@ -142,44 +152,46 @@ export const fetchurl = (args: NixValue): string => {
     name ?? null,
     executable ?? false,
   );
-  return result.store_path;
+  const context: NixStringContext = new Set();
+  addOpaqueContext(context, result.storePath);
+  return mkStringWithContext(result.storePath, context);
 };
 
-export const fetchTarball = (args: NixValue): string => {
-  const { url, hash, narHash, name } = normalizeTarballInput(args);
-  const result: FetchTarballResult = Deno.core.ops.op_fetch_tarball(
-    url,
-    hash ?? null,
-    narHash ?? null,
-    name ?? null,
-  );
-  return result.store_path;
+export const fetchTarball = (args: NixValue): NixString => {
+  const { url, name, sha256 } = normalizeTarballInput(args);
+  const result: FetchTarballResult = Deno.core.ops.op_fetch_tarball(url, name ?? null, sha256 ?? null);
+  const context: NixStringContext = new Set();
+  addOpaqueContext(context, result.storePath);
+  return mkStringWithContext(result.storePath, context);
 };
 
 export const fetchGit = (args: NixValue): NixAttrs => {
   const forced = force(args);
-  if (typeof forced === "string" || isPath(forced)) {
-    const path = coerceToPath(forced);
-    const result: FetchGitResult = Deno.core.ops.op_fetch_git(path, null, null, false, false, false, null);
-    return {
-      outPath: result.out_path,
-      rev: result.rev,
-      shortRev: result.short_rev,
-      revCount: BigInt(result.rev_count),
-      lastModified: BigInt(result.last_modified),
-      lastModifiedDate: result.last_modified_date,
-      submodules: result.submodules,
-      narHash: result.nar_hash,
-    };
+  const disposedContext: NixStringContext = new Set();
+  if (isString(forced) || isPath(forced)) {
+    const url = coerceToString(forced, StringCoercionMode.Base, false, disposedContext);
+    const result = Deno.core.ops.op_fetch_git(url, null, null, false, false, false, null);
+    const outContext: NixStringContext = new Set();
+    addOpaqueContext(outContext, result.outPath);
+    return new Map<string, NixValue>([
+      ["outPath", mkStringWithContext(result.outPath, outContext)],
+      ["rev", result.rev],
+      ["shortRev", result.shortRev],
+      ["revCount", BigInt(result.revCount)],
+      ["lastModified", BigInt(result.lastModified)],
+      ["lastModifiedDate", result.lastModifiedDate],
+      ["submodules", result.submodules],
+      ["narHash", result.narHash],
+    ]);
   }
   const attrs = forceAttrs(args);
-  const url = forceStringValue(attrs.url);
-  const gitRef = "ref" in attrs ? forceStringValue(attrs.ref) : null;
-  const rev = "rev" in attrs ? forceStringValue(attrs.rev) : null;
-  const shallow = "shallow" in attrs ? forceBool(attrs.shallow) : false;
-  const submodules = "submodules" in attrs ? forceBool(attrs.submodules) : false;
-  const allRefs = "allRefs" in attrs ? forceBool(attrs.allRefs) : false;
-  const name = "name" in attrs ? forceStringValue(attrs.name) : null;
+  const url = forceStringValue(select(attrs, ["url"]));
+  const gitRef = attrs.has("ref") ? forceStringValue(attrs.get("ref") as NixValue) : null;
+  const rev = attrs.has("rev") ? forceStringValue(attrs.get("rev") as NixValue) : null;
+  const shallow = attrs.has("shallow") ? forceBool(attrs.get("shallow") as NixValue) : false;
+  const submodules = attrs.has("submodules") ? forceBool(attrs.get("submodules") as NixValue) : false;
+  const allRefs = attrs.has("allRefs") ? forceBool(attrs.get("allRefs") as NixValue) : false;
+  const name = attrs.has("name") ? forceStringValue(attrs.get("name") as NixValue) : null;
 
   const result: FetchGitResult = Deno.core.ops.op_fetch_git(
     url,
@@ -191,38 +203,27 @@ export const fetchGit = (args: NixValue): NixAttrs => {
     name,
   );
 
-  return {
-    outPath: result.out_path,
-    rev: result.rev,
-    shortRev: result.short_rev,
-    revCount: BigInt(result.rev_count),
-    lastModified: BigInt(result.last_modified),
-    lastModifiedDate: result.last_modified_date,
-    submodules: result.submodules,
-    narHash: result.nar_hash,
-  };
+  const outContext: NixStringContext = new Set();
+  addOpaqueContext(outContext, result.outPath);
+  return new Map<string, NixValue>([
+    ["outPath", mkStringWithContext(result.outPath, outContext)],
+    ["rev", result.rev],
+    ["shortRev", result.shortRev],
+    ["revCount", BigInt(result.revCount)],
+    ["lastModified", BigInt(result.lastModified)],
+    ["lastModifiedDate", result.lastModifiedDate],
+    ["submodules", result.submodules],
+    ["narHash", result.narHash],
+  ]);
 };
 
-export const fetchMercurial = (args: NixValue): NixAttrs => {
-  const attrs = forceAttrs(args);
-  const url = forceStringValue(attrs.url);
-  const rev = "rev" in attrs ? forceStringValue(attrs.rev) : null;
-  const name = "name" in attrs ? forceStringValue(attrs.name) : null;
-
-  const result: FetchHgResult = Deno.core.ops.op_fetch_hg(url, rev, name);
-
-  return {
-    outPath: result.out_path,
-    branch: result.branch,
-    rev: result.rev,
-    shortRev: result.short_rev,
-    revCount: BigInt(result.rev_count),
-  };
+export const fetchMercurial = (_args: NixValue): NixAttrs => {
+  throw new Error("Not implemented: fetchMercurial");
 };
 
 export const fetchTree = (args: NixValue): NixAttrs => {
   const attrs = forceAttrs(args);
-  const type = "type" in attrs ? forceStringValue(attrs.type) : "auto";
+  const type = attrs.has("type") ? forceStringValue(attrs.get("type") as NixValue) : "auto";
 
   switch (type) {
     case "git":
@@ -231,29 +232,31 @@ export const fetchTree = (args: NixValue): NixAttrs => {
     case "mercurial":
       return fetchMercurial(args);
     case "tarball":
-      return { outPath: fetchTarball(args) };
+      return new Map<string, NixValue>([["outPath", fetchTarball(args)]]);
     case "file":
-      return { outPath: fetchurl(args) };
+      return new Map<string, NixValue>([["outPath", fetchurl(args)]]);
     case "path": {
-      const path = forceStringValue(attrs.path);
-      return { outPath: path };
+      const path = forceStringValue(select(attrs, ["path"]));
+      return new Map<string, NixValue>([["outPath", path]]);
     }
     case "github":
     case "gitlab":
     case "sourcehut":
       return fetchGitForge(type, attrs);
-    case "auto":
     default:
       return autoDetectAndFetch(attrs);
   }
 };
 
 const fetchGitForge = (forge: string, attrs: NixAttrs): NixAttrs => {
-  const owner = forceStringValue(attrs.owner);
-  const repo = forceStringValue(attrs.repo);
-  const rev =
-    "rev" in attrs ? forceStringValue(attrs.rev) : "ref" in attrs ? forceStringValue(attrs.ref) : "HEAD";
-  const host = "host" in attrs ? forceStringValue(attrs.host) : undefined;
+  const owner = forceStringValue(select(forge, ["owner"]));
+  const repo = forceStringValue(select(forge, ["repo"]));
+  const rev = attrs.has("rev")
+    ? forceStringValue(attrs.get("rev") as NixValue)
+    : attrs.has("ref")
+      ? forceStringValue(attrs.get("ref") as NixValue)
+      : "HEAD";
+  const host = attrs.has("host") ? forceStringValue(attrs.get("host") as NixValue) : undefined;
 
   let tarballUrl: string;
   switch (forge) {
@@ -276,17 +279,17 @@ const fetchGitForge = (forge: string, attrs: NixAttrs): NixAttrs => {
       throw new Error(`Unknown forge type: ${forge}`);
   }
 
-  const outPath = fetchTarball({ url: tarballUrl, ...attrs });
+  const outPath = fetchTarball(new Map<string, NixValue>([["url", tarballUrl], ...attrs]));
 
-  return {
-    outPath,
-    rev,
-    shortRev: rev.substring(0, 7),
-  };
+  return new Map<string, NixValue>([
+    ["outPath", outPath],
+    ["rev", rev],
+    ["shortRev", rev.substring(0, 7)],
+  ]);
 };
 
 const autoDetectAndFetch = (attrs: NixAttrs): NixAttrs => {
-  const url = forceStringValue(attrs.url);
+  const url = forceStringValue(select(attrs, ["url"]));
   if (url.endsWith(".git") || url.includes("github.com") || url.includes("gitlab.com")) {
     return fetchGit(attrs);
   }
@@ -296,34 +299,33 @@ const autoDetectAndFetch = (attrs: NixAttrs): NixAttrs => {
     url.endsWith(".tar.bz2") ||
     url.endsWith(".tgz")
   ) {
-    return { outPath: fetchTarball(attrs) };
+    return new Map<string, NixValue>([["outPath", fetchTarball(attrs)]]);
   }
-  return { outPath: fetchurl(attrs) };
+  return new Map<string, NixValue>([["outPath", fetchurl(attrs)]]);
 };
 
 export const readDir = (path: NixValue): NixAttrs => {
-  const pathStr = coerceToPath(path);
-  const entries: Record<string, string> = Deno.core.ops.op_read_dir(pathStr);
-  const result: NixAttrs = {};
-  for (const [name, type] of Object.entries(entries)) {
-    result[name] = type;
-  }
-  return result;
+  const pathStr = realisePath(path);
+  return Deno.core.ops.op_read_dir(pathStr);
 };
 
 export const readFile = (path: NixValue): string => {
-  const pathStr = coerceToPath(path);
+  const pathStr = realisePath(path);
   return Deno.core.ops.op_read_file(pathStr);
 };
 
 export const readFileType = (path: NixValue): string => {
-  const pathStr = coerceToPath(path);
+  const pathStr = realisePath(path);
   return Deno.core.ops.op_read_file_type(pathStr);
 };
 
 export const pathExists = (path: NixValue): boolean => {
-  const pathStr = coerceToPath(path);
+  try {
+    const pathStr = realisePath(path);
     return Deno.core.ops.op_path_exists(pathStr);
+  } catch {
+    return false;
+  }
 };
 
 /**
@@ -333,48 +335,57 @@ export const pathExists = (path: NixValue): boolean => {
  * Parameters (attribute set):
  * - path (required): Path to add to the store
  * - name (optional): Name to use in store path (defaults to basename)
- * - filter (optional): Function (path, type) -> bool (NOT IMPLEMENTED YET)
+ * - filter (optional): Function (path, type) -> bool
  * - recursive (optional): Boolean, default true (NAR vs flat hashing)
  * - sha256 (optional): Expected SHA-256 hash (hex-encoded)
  *
  * Returns: Store path string
  */
-export const path = (args: NixValue): string => {
+export const path = (args: NixValue): NixString => {
   const attrs = forceAttrs(args);
 
-  // Required: path parameter
-  if (!("path" in attrs)) {
+  if (!attrs.has("path")) {
     throw new TypeError("builtins.path: 'path' attribute is required");
   }
 
-  const pathValue = force(attrs.path);
+  const pathValue = force(attrs.get("path") as NixValue);
   let pathStr: string;
 
-  // Accept both Path values and strings
   if (isNixPath(pathValue)) {
     pathStr = getPathValue(pathValue);
   } else {
     pathStr = forceStringValue(pathValue);
   }
 
-  // Optional: name parameter (defaults to basename in Rust)
-  const name = "name" in attrs ? forceStringValue(attrs.name) : null;
+  const name = attrs.has("name") ? forceStringValue(attrs.get("name") as NixValue) : null;
+  const recursive = attrs.has("recursive") ? forceBool(attrs.get("recursive") as NixValue) : true;
+  const sha256 = attrs.has("sha256") ? forceStringValue(attrs.get("sha256") as NixValue) : null;
 
-  // Optional: recursive parameter (default: true)
-  const recursive = "recursive" in attrs ? forceBool(attrs.recursive) : true;
+  let storePath: string;
 
-  // Optional: sha256 parameter
-  const sha256 = "sha256" in attrs ? forceStringValue(attrs.sha256) : null;
+  if (attrs.has("filter")) {
+    const filterFn = forceFunction(attrs.get("filter") as NixValue);
 
-  // TODO: Handle filter parameter
-  if ("filter" in attrs) {
-    throw new Error("builtins.path: 'filter' parameter is not yet implemented");
+    const entries: [string, string][] = Deno.core.ops.op_walk_dir(pathStr);
+
+    const includePaths: string[] = [];
+    for (const [relPath, fileType] of entries) {
+      const fullPath = `${pathStr}/${relPath}`;
+      const innerFn = forceFunction(filterFn(fullPath));
+      const shouldInclude = force(innerFn(fileType));
+      if (shouldInclude === true) {
+        includePaths.push(relPath);
+      }
     }
 
-  // Call Rust op to add path to store
-  const storePath: string = Deno.core.ops.op_add_path(pathStr, name, recursive, sha256);
+    storePath = Deno.core.ops.op_add_filtered_path(pathStr, name, recursive, sha256, includePaths);
+  } else {
+    storePath = Deno.core.ops.op_add_path(pathStr, name, recursive, sha256);
+  }
 
-  return storePath;
+  const context: NixStringContext = new Set();
+  addOpaqueContext(context, storePath);
+  return mkStringWithContext(storePath, context);
 };
 
 export const toFile =
@@ -399,11 +410,9 @@ export const toFile =
     return mkStringWithContext(storePath, new Set([storePath]));
   };
 
-export const toPath = (name: NixValue, s: NixValue): never => {
-  throw new Error("Not implemented: toPath");
-};
-
-export const filterSource = (args: NixValue): never => {
+export const filterSource =
+  (_filter: NixValue) =>
+  (_path: NixValue): never => {
     throw new Error("Not implemented: filterSource");
   };
 
@@ -432,9 +441,9 @@ export const findFile =
     for (const item of forcedSearchPath) {
       const attrs = forceAttrs(item);
 
-      const prefix = "prefix" in attrs ? forceStringNoCtx(attrs.prefix) : "";
+      const prefix = attrs.has("prefix") ? forceStringNoCtx(attrs.get("prefix") as NixValue) : "";
 
-      if (!("path" in attrs)) {
+      if (!attrs.has("path")) {
         throw new Error("findFile: search path element is missing 'path' attribute");
       }
 
@@ -444,25 +453,29 @@ export const findFile =
       }
 
       const context: NixStringContext = new Set();
-      const pathVal = coerceToString(attrs.path, StringCoercionMode.Interpolation, false, context);
+      const pathVal = coerceToString(
+        attrs.get("path") as NixValue,
+        StringCoercionMode.Interpolation,
+        false,
+        context,
+      );
 
       if (context.size > 0) {
         throw new Error("findFile: path with string context is not yet supported");
       }
 
       const resolvedPath = Deno.core.ops.op_resolve_path(pathVal, "");
-      const candidatePath = suffix.length > 0
-        ? Deno.core.ops.op_resolve_path(suffix, resolvedPath)
-        : resolvedPath;
+      const candidatePath =
+        suffix.length > 0 ? Deno.core.ops.op_resolve_path(suffix, resolvedPath) : resolvedPath;
 
       if (Deno.core.ops.op_path_exists(candidatePath)) {
-        return { [IS_PATH]: true, value: candidatePath };
+        return new NixPath(candidatePath);
       }
     }
 
     if (lookupPathStr.startsWith("nix/")) {
       // FIXME: special path type
-      return { [IS_PATH]: true, value: `<${lookupPathStr}>` };
+      return new NixPath(`<${lookupPathStr}>`);
     }
 
     throw new CatchableError(`file '${lookupPathStr}' was not found in the Nix search path`);

nix-js/runtime-ts/src/builtins/list.ts

@@ -1,12 +1,7 @@
-/**
- * List operation builtin functions
- * All functions are properly curried
- */
-
-import type { NixValue, NixList, NixAttrs } from "../types";
-import { force } from "../thunk";
-import { forceList, forceFunction, forceInt, forceBool } from "../type-assert";
 import { op } from "../operators";
+import { force } from "../thunk";
+import { forceBool, forceFunction, forceInt, forceList } from "../type-assert";
+import type { NixAttrs, NixList, NixValue } from "../types";
 
 export const map =
   (f: NixValue) =>
@@ -74,23 +69,23 @@ export const concatMap =
   };
 
 export const foldlPrime =
-  (op_fn: NixValue) =>
+  (opFn: NixValue) =>
   (nul: NixValue) =>
   (list: NixValue): NixValue => {
-    const forced_op = forceFunction(op_fn);
+    const forcedOp = forceFunction(opFn);
     return forceList(list).reduce((acc: NixValue, cur: NixValue) => {
-      return forceFunction(forced_op(acc))(cur);
+      return forceFunction(forcedOp(acc))(cur);
     }, nul);
   };
 
 export const sort =
   (cmp: NixValue) =>
   (list: NixValue): NixList => {
-    const forced_list = [...forceList(list)];
-    const forced_cmp = forceFunction(cmp);
-    return forced_list.sort((a, b) => {
-      if (force(forceFunction(forced_cmp(a))(b))) return -1;
-      if (force(forceFunction(forced_cmp(b))(a))) return 1;
+    const forcedList = [...forceList(list)];
+    const forcedCmp = forceFunction(cmp);
+    return forcedList.sort((a, b) => {
+      if (force(forceFunction(forcedCmp(a))(b))) return -1;
+      if (force(forceFunction(forcedCmp(b))(a))) return 1;
       return 0;
     });
   };
@@ -98,20 +93,21 @@ export const sort =
 export const partition =
   (pred: NixValue) =>
   (list: NixValue): NixAttrs => {
-    const forced_list = forceList(list);
-    const forced_pred = forceFunction(pred);
-    const attrs = {
-      right: [] as NixList,
-      wrong: [] as NixList,
-    };
-    for (const elem of forced_list) {
-      if (force(forced_pred(elem))) {
-        attrs.right.push(elem);
+    const forcedList = forceList(list);
+    const forcedPred = forceFunction(pred);
+    const right: NixList = [];
+    const wrong: NixList = [];
+    for (const elem of forcedList) {
+      if (force(forcedPred(elem))) {
+        right.push(elem);
       } else {
-        attrs.wrong.push(elem);
+        wrong.push(elem);
       }
     }
-    return attrs;
+    return new Map<string, NixValue>([
+      ["right", right],
+      ["wrong", wrong],
+    ]);
   };
 
 export const genList =

nix-js/runtime-ts/src/builtins/math.ts

@@ -1,9 +1,5 @@
-/**
- * Math builtin functions
- */
-
-import type { NixValue } from "../types";
 import { forceNumeric } from "../type-assert";
+import type { NixValue } from "../types";
 
 export const ceil = (x: NixValue): bigint => {
   const val = forceNumeric(x);

nix-js/runtime-ts/src/builtins/misc.ts

@@ -1,24 +1,28 @@
-/**
- * Miscellaneous builtin functions
- */
-
-import { force } from "../thunk";
-import { CatchableError } from "../types";
-import type { NixAttrs, NixBool, NixStrictValue, NixValue } from "../types";
-import { forceList, forceAttrs, forceFunction, forceStringValue, forceString, forceStringNoCtx } from "../type-assert";
-import * as context from "./context";
-import { compareValues } from "../operators";
-import { isBool, isFloat, isInt, isList, isString, typeOf } from "./type-check";
 import { OrderedSet } from "js-sdsl";
+import { select } from "../helpers";
+import { compareValues } from "../operators";
 import {
-  type NixStringContext,
-  getStringValue,
   getStringContext,
+  getStringValue,
   mkStringWithContext,
+  type NixStringContext,
 } from "../string-context";
+import { force } from "../thunk";
+import {
+  forceAttrs,
+  forceFunction,
+  forceList,
+  forceString,
+  forceStringNoCtx,
+  forceStringValue,
+} from "../type-assert";
+import type { NixAttrs, NixStrictValue, NixValue } from "../types";
+import { ATTR_POSITIONS, CatchableError } from "../types";
+import * as context from "./context";
+import { isBool, isFloat, isInt, isList, isString, typeOf } from "./type-check";
 
 export const addErrorContext =
-  (e1: NixValue) =>
+  (_e1: NixValue) =>
   (e2: NixValue): NixValue => {
     // FIXME:
     // console.log("[WARNING]: addErrorContext not implemented");
@@ -31,22 +35,6 @@ export const getContext = context.getContext;
 
 export const hasContext = context.hasContext;
 
-export const hashFile =
-  (type: NixValue) =>
-  (p: NixValue): never => {
-    throw new Error("Not implemented: hashFile");
-  };
-
-export const hashString =
-  (type: NixValue) =>
-  (p: NixValue): never => {
-    throw new Error("Not implemented: hashString");
-  };
-
-export const convertHash = (args: NixValue): never => {
-  throw new Error("Not implemented: convertHash");
-};
-
 export const unsafeDiscardOutputDependency = context.unsafeDiscardOutputDependency;
 
 export const unsafeDiscardStringContext = context.unsafeDiscardStringContext;
@@ -69,9 +57,9 @@ export const compareVersions =
       i1 = c1.nextIndex;
       i2 = c2.nextIndex;
 
-      if (componentsLT(c1.component, c2.component)) {
+      if (componentsLt(c1.component, c2.component)) {
         return -1n;
-      } else if (componentsLT(c2.component, c1.component)) {
+      } else if (componentsLt(c2.component, c1.component)) {
         return 1n;
       }
     }
@@ -113,7 +101,7 @@ function nextComponent(s: string, startIdx: number): ComponentResult {
   return { component: s.substring(start, p), nextIndex: p };
 }
 
-function componentsLT(c1: string, c2: string): boolean {
+function componentsLt(c1: string, c2: string): boolean {
   const n1 = c1.match(/^[0-9]+$/) ? BigInt(c1) : null;
   const n2 = c2.match(/^[0-9]+$/) ? BigInt(c2) : null;
 
@@ -147,27 +135,23 @@ function componentsLT(c1: string, c2: string): boolean {
   return c1 < c2;
 }
 
-export const dirOf = (s: NixValue): never => {
-  throw new Error("Not implemented: dirOf");
-};
-
-export const flakeRefToString = (attrs: NixValue): never => {
-  throw new Error("Not implemented: flakeRefToString");
-};
-
 export const functionArgs = (f: NixValue): NixAttrs => {
   const func = forceFunction(f);
   if (func.args) {
-    const ret: NixAttrs = {};
-    for (const key of func.args!.required) {
-      ret[key] = false;
+    const ret: NixAttrs = new Map();
+    for (const key of func.args.required) {
+      ret.set(key, false);
     }
-    for (const key of func.args!.optional) {
-      ret[key] = true;
+    for (const key of func.args.optional) {
+      ret.set(key, true);
+    }
+    const positions = func.args.positions;
+    if (positions) {
+      ret[ATTR_POSITIONS] = positions;
     }
     return ret;
   }
-  return {};
+  return new Map();
 };
 
 const checkComparable = (value: NixStrictValue): void => {
@@ -179,7 +163,8 @@ const checkComparable = (value: NixStrictValue): void => {
 
 export const genericClosure = (args: NixValue): NixValue => {
   const forcedArgs = forceAttrs(args);
-  const { startSet, operator } = forcedArgs;
+  const startSet = select(forcedArgs, ["startSet"]);
+  const operator = select(forcedArgs, ["operator"]);
 
   const initialList = forceList(startSet);
   const opFunction = forceFunction(operator);
@@ -190,7 +175,7 @@ export const genericClosure = (args: NixValue): NixValue => {
 
   for (const item of initialList) {
     const itemAttrs = forceAttrs(item);
-    const key = force(itemAttrs.key);
+    const key = force(select(itemAttrs, ["key"]));
     checkComparable(key);
     if (resultSet.find(key).equals(resultSet.end())) {
       resultSet.insert(key);
@@ -206,7 +191,7 @@ export const genericClosure = (args: NixValue): NixValue => {
 
     for (const newItem of newItems) {
       const newItemAttrs = forceAttrs(newItem);
-      const key = force(newItemAttrs.key);
+      const key = force(select(newItemAttrs, ["key"]));
       checkComparable(key);
       if (resultSet.find(key).equals(resultSet.end())) {
         resultSet.insert(key);
@@ -219,14 +204,10 @@ export const genericClosure = (args: NixValue): NixValue => {
   return resultList;
 };
 
-export const getFlake = (attrs: NixValue): never => {
-  throw new Error("Not implemented: getFlake");
-};
-
 export const outputOf =
-  (drv: NixValue) =>
-  (out: NixValue): never => {
-    throw new Error("Not implemented: outputOf");
+  (_drv: NixValue) =>
+  (_out: NixValue): never => {
+    throw new Error("Not implemented: outputOf (part of dynamic-derivation)");
   };
 
 export const parseDrvName = (s: NixValue): NixAttrs => {
@@ -234,28 +215,21 @@ export const parseDrvName = (s: NixValue): NixAttrs => {
   let name = fullName;
   let version = "";
   for (let i = 0; i < fullName.length; ++i) {
-    if (fullName[i] === '-' && i + 1 < fullName.length && !/[a-zA-Z]/.test(fullName[i + 1])) {
+    if (fullName[i] === "-" && i + 1 < fullName.length && !/[a-zA-Z]/.test(fullName[i + 1])) {
       name = fullName.substring(0, i);
       version = fullName.substring(i + 1);
       break;
     }
   }
-  return {
-    name,
-    version
-  }
+  return new Map<string, NixValue>([
+    ["name", name],
+    ["version", version],
+  ]);
 };
 
-export const parseFlakeName = (s: NixValue): never => {
-  throw new Error("Not implemented: parseFlakeName");
-};
-
-export const parseFlakeRef = (s: NixValue): never => {
-  throw new Error("Not implemented: parseFlakeRef");
-};
-
-export const placeholder = (output: NixValue): never => {
-  throw new Error("Not implemented: placeholder");
+export const placeholder = (output: NixValue): NixValue => {
+  const outputStr = forceStringNoCtx(output);
+  return Deno.core.ops.op_make_placeholder(outputStr);
 };
 
 export const replaceStrings =
@@ -297,7 +271,7 @@ export const replaceStrings =
               resultContext.add(elem);
             }
           }
-          const replacement = toCache.get(i)!;
+          const replacement = toCache.get(i) as string;
 
           result += replacement;
 
@@ -344,22 +318,25 @@ export const splitVersion = (s: NixValue): NixValue => {
   return components;
 };
 
-export const traceVerbose = (e1: NixValue, e2: NixValue): never => {
-  throw new Error("Not implemented: traceVerbose");
+export const traceVerbose =
+  (_e1: NixValue) =>
+  (e2: NixValue): NixStrictValue => {
+    // TODO: implement traceVerbose
+    return force(e2);
   };
 
-export const tryEval = (e: NixValue): { success: NixBool; value: NixStrictValue } => {
+export const tryEval = (e: NixValue): NixAttrs => {
   try {
-    return {
-      success: true,
-      value: force(e),
-    };
+    return new Map<string, NixValue>([
+      ["success", true],
+      ["value", force(e)],
+    ]);
   } catch (err) {
     if (err instanceof CatchableError) {
-      return {
-        success: false,
-        value: false,
-      };
+      return new Map<string, NixValue>([
+        ["success", false],
+        ["value", false],
+      ]);
     } else {
       throw err;
     }

nix-js/runtime-ts/src/builtins/path.ts

@@ -1,13 +1,9 @@
-/**
- * Path-related builtin functions
- */
-
-import type { NixValue, NixString, NixPath } from "../types";
-import { isNixPath, isStringWithContext } from "../types";
-import { force } from "../thunk";
 import { mkPath } from "../path";
-import { coerceToString, StringCoercionMode, coerceToPath } from "./conversion";
 import { mkStringWithContext, type NixStringContext } from "../string-context";
+import { force } from "../thunk";
+import type { NixPath, NixString, NixValue } from "../types";
+import { isNixPath } from "../types";
+import { coerceToPath, coerceToString, StringCoercionMode } from "./conversion";
 
 /**
  * builtins.baseNameOf
@@ -25,36 +21,6 @@ import { mkStringWithContext, type NixStringContext } from "../string-context";
  * - baseNameOf "foo" → "foo"
  */
 export const baseNameOf = (s: NixValue): NixString => {
-  const forced = force(s);
-
-  // Path input → string output (no context)
-  if (isNixPath(forced)) {
-    const pathStr = forced.value;
-
-    if (pathStr.length === 0) {
-      return "";
-    }
-
-    let last = pathStr.length - 1;
-    if (pathStr[last] === "/" && last > 0) {
-      last -= 1;
-    }
-
-    let pos = last;
-    while (pos >= 0 && pathStr[pos] !== "/") {
-      pos -= 1;
-    }
-
-    if (pos === -1) {
-      pos = 0;
-    } else {
-      pos += 1;
-    }
-
-    return pathStr.substring(pos, last + 1);
-  }
-
-  // String input → string output (preserve context)
   const context: NixStringContext = new Set();
   const pathStr = coerceToString(s, StringCoercionMode.Base, false, context);
 
@@ -120,21 +86,8 @@ export const dirOf = (s: NixValue): NixPath | NixString => {
   }
 
   // String input → string output
-  const strValue: NixString = coerceToString(s, StringCoercionMode.Base, false) as NixString;
-
-  let pathStr: string;
-  let hasContext = false;
-  let originalContext: Set<string> | undefined;
-
-  if (typeof strValue === "string") {
-    pathStr = strValue;
-  } else if (isStringWithContext(strValue)) {
-    pathStr = strValue.value;
-    hasContext = strValue.context.size > 0;
-    originalContext = strValue.context;
-  } else {
-    pathStr = strValue as string;
-  }
+  const outContext: NixStringContext = new Set();
+  const pathStr = coerceToString(s, StringCoercionMode.Base, false, outContext);
 
   const lastSlash = pathStr.lastIndexOf("/");
 
@@ -147,9 +100,8 @@ export const dirOf = (s: NixValue): NixPath | NixString => {
 
   const result = pathStr.slice(0, lastSlash);
 
-  // Preserve string context if present
-  if (hasContext && originalContext) {
-    return mkStringWithContext(result, originalContext);
+  if (outContext.size > 0) {
+    return mkStringWithContext(result, outContext);
   }
 
   return result;

nix-js/runtime-ts/src/builtins/string.ts

@@ -1,29 +1,15 @@
-/**
- * String operation builtin functions
- */
-
-import type { NixInt, NixValue, NixString } from "../types";
-import { forceStringValue, forceList, forceInt, forceString } from "../type-assert";
-import { coerceToString, StringCoercionMode } from "./conversion";
 import {
-  type NixStringContext,
-  getStringValue,
   getStringContext,
+  getStringValue,
   mkStringWithContext,
+  type NixStringContext,
 } from "../string-context";
+import { forceInt, forceList, forceString, forceStringValue } from "../type-assert";
+import type { NixInt, NixString, NixValue } from "../types";
+import { coerceToString, StringCoercionMode } from "./conversion";
 
 export const stringLength = (e: NixValue): NixInt => BigInt(forceStringValue(e).length);
 
-/**
- * builtins.substring - Extract substring while preserving string context
- *
- * IMPORTANT: String context must be preserved from the source string.
- * This matches Lix behavior where substring operations maintain references
- * to store paths and derivations.
- *
- * Special case: substring 0 0 str can be used idiomatically to capture
- * string context efficiently without copying the string value.
- */
 export const substring =
   (start: NixValue) =>
   (len: NixValue) =>
@@ -55,13 +41,6 @@ export const substring =
     return mkStringWithContext(result, context);
   };
 
-/**
- * builtins.concatStringsSep - Concatenate strings with separator, merging contexts
- *
- * IMPORTANT: String context must be collected from both the separator and all
- * list elements, then merged into the result. This ensures that store path
- * references are preserved when building paths like "/nix/store/xxx/bin:/nix/store/yyy/bin".
- */
 export const concatStringsSep =
   (sep: NixValue) =>
   (list: NixValue): NixString => {
@@ -80,81 +59,17 @@ export const concatStringsSep =
     return mkStringWithContext(result, context);
   };
 
-const POSIX_CLASSES: Record<string, string> = {
-  alnum: "a-zA-Z0-9",
-  alpha: "a-zA-Z",
-  blank: " \\t",
-  digit: "0-9",
-  lower: "a-z",
-  upper: "A-Z",
-  space: "\\s",
-  xdigit: "0-9A-Fa-f",
-  punct: "\\-!\"#$%&'()*+,./:;<=>?@[\\\\\\]^_`{|}~",
-};
-
-function posixToJsRegex(pattern: string, fullMatch: boolean = false): RegExp {
-  let jsPattern = pattern;
-
-  jsPattern = jsPattern.replace(/\[(\^?)(?:\[:(\w+):\])+\]/g, (match) => {
-    const isNegated = match[1] === "^";
-    const classNames = [...match.matchAll(/\[:(\w+):\]/g)].map((m) => m[1]);
-
-    const combined = classNames
-      .map((className) => {
-        const replacement = POSIX_CLASSES[className];
-        if (!replacement) {
-          throw new Error(`Unknown POSIX character class: ${className}`);
-        }
-        return replacement;
-      })
-      .join("");
-
-    return isNegated ? `[^${combined}]` : `[${combined}]`;
-  });
-
-  jsPattern = jsPattern.replace(/\[:(\w+):\]/g, (_match, className) => {
-    const replacement = POSIX_CLASSES[className];
-    if (!replacement) {
-      throw new Error(`Unknown POSIX character class: ${className}`);
-    }
-    return replacement;
-  });
-
-  if (fullMatch) {
-    if (!jsPattern.startsWith("^")) {
-      jsPattern = "^" + jsPattern;
-    }
-    if (!jsPattern.endsWith("$")) {
-      jsPattern = jsPattern + "$";
-    }
-  }
-
-  return new RegExp(jsPattern, "u");
-}
-
 export const match =
   (regex: NixValue) =>
   (str: NixValue): NixValue => {
     const regexStr = forceStringValue(regex);
     const inputStr = forceStringValue(str);
 
-    try {
-      const re = posixToJsRegex(regexStr, true);
-      const result = inputStr.match(re);
-
-      if (!result) {
+    const result = Deno.core.ops.op_match(regexStr, inputStr);
+    if (result === null) {
       return null;
     }
-
-      const groups: NixValue[] = [];
-      for (let i = 1; i < result.length; i++) {
-        groups.push(result[i] !== undefined ? result[i] : null);
-      }
-
-      return groups;
-    } catch (e) {
-      throw new Error(`Invalid regular expression '${regexStr}': ${e}`);
-    }
+    return result.map((g) => (g !== null ? g : null));
   };
 
 export const split =
@@ -164,37 +79,16 @@ export const split =
     const inputStr = forceString(str);
     const inputStrValue = getStringValue(inputStr);
 
-    try {
-      const re = posixToJsRegex(regexStr);
-      const reGlobal = new RegExp(re.source, re.flags + "g");
+    const result = Deno.core.ops.op_split(regexStr, inputStrValue);
 
-      const result: NixValue[] = [];
-      let lastIndex = 0;
-      let match: RegExpExecArray | null;
-
-      while ((match = reGlobal.exec(inputStrValue)) !== null) {
-        result.push(inputStrValue.substring(lastIndex, match.index));
-
-        const groups: NixValue[] = [];
-        for (let i = 1; i < match.length; i++) {
-          groups.push(match[i] !== undefined ? match[i] : null);
-        }
-        result.push(groups);
-
-        lastIndex = match.index + match[0].length;
-
-        if (match[0].length === 0) {
-          reGlobal.lastIndex++;
-        }
-      }
-
-      if (lastIndex === 0) {
+    if (result.length === 1 && typeof result[0] === "string") {
       return [inputStr];
     }
 
-      result.push(inputStrValue.substring(lastIndex));
-      return result;
-    } catch (e) {
-      throw new Error(`Invalid regular expression '${regexStr}': ${e}`);
+    return result.map((item) => {
+      if (typeof item === "string") {
+        return item;
       }
+      return item.map((g) => (g !== null ? g : null));
+    });
   };

nix-js/runtime-ts/src/builtins/type-check.ts

@@ -1,12 +1,6 @@
-/**
- * Type checking builtin functions
- */
-
 import {
-  HAS_CONTEXT,
   isNixPath,
   isStringWithContext,
-  type NixPath,
   type NixAttrs,
   type NixBool,
   type NixFloat,
@@ -14,23 +8,17 @@ import {
   type NixInt,
   type NixList,
   type NixNull,
-  type NixString,
+  type NixPath,
   type NixStrictValue,
+  type NixString,
 } from "../types";
 
-/**
- * Check if a value is a Nix string (plain string or StringWithContext)
- * This works on already-forced values (NixStrictValue).
- */
 export const isNixString = (v: NixStrictValue): v is NixString => {
   return typeof v === "string" || isStringWithContext(v);
 };
 
 export const isAttrs = (e: NixStrictValue): e is NixAttrs => {
-  const val = e;
-  return (
-    typeof val === "object" && !Array.isArray(val) && val !== null && !(HAS_CONTEXT in val) && !isPath(val)
-  );
+  return e instanceof Map;
 };
 
 export const isBool = (e: NixStrictValue): e is NixBool => typeof e === "boolean";
@@ -68,7 +56,7 @@ export const typeOf = (e: NixStrictValue): NixType => {
   if (isNixString(e)) return "string";
   if (isNixPath(e)) return "path";
   if (Array.isArray(e)) return "list";
-  if (typeof e === "object") return "set";
+  if (e instanceof Map) return "set";
   if (typeof e === "function") return "lambda";
 
   throw new TypeError(`Unknown Nix type: ${typeof e}`);

nix-js/runtime-ts/src/conversion.ts

@@ -1,59 +0,0 @@
-import { HAS_CONTEXT, NixStringContext } from "./string-context";
-import { force } from "./thunk";
-import type { NixValue } from "./types";
-
-export const nixValueToJson = (
-  value: NixValue,
-  seen = new Set<object>(),
-  outContext?: NixStringContext,
-): any => {
-  const v = force(value);
-
-  if (v === null) return null;
-  if (typeof v === "boolean") return v;
-  if (typeof v === "string") return v;
-  if (typeof v === "number") return v;
-
-  if (typeof v === "object" && HAS_CONTEXT in v && "context" in v) {
-    if (outContext) {
-      for (const elem of v.context) {
-        outContext.add(elem);
-      }
-    }
-    return v.value;
-  }
-
-  if (typeof v === "bigint") {
-    const num = Number(v);
-    if (v > Number.MAX_SAFE_INTEGER || v < Number.MIN_SAFE_INTEGER) {
-      console.warn(`derivation: integer ${v} exceeds safe range, precision may be lost in __structuredAttrs`);
-    }
-    return num;
-  }
-
-  if (typeof v === "object" && v !== null) {
-    if (seen.has(v)) {
-      throw new Error("derivation: circular reference detected in __structuredAttrs");
-    }
-    // FIXME: tryAttrsToString
-    seen.add(v);
-  }
-
-  if (Array.isArray(v)) {
-    return v.map((item) => nixValueToJson(item, seen, outContext));
-  }
-
-  if (typeof v === "object") {
-    const result: Record<string, any> = {};
-    for (const [key, val] of Object.entries(v)) {
-      result[key] = nixValueToJson(val, seen, outContext);
-    }
-    return result;
-  }
-
-  if (typeof v === "function") {
-    throw new Error("derivation: cannot serialize function in __structuredAttrs");
-  }
-
-  throw new Error(`derivation: cannot serialize ${typeof v} to JSON`);
-};

nix-js/runtime-ts/src/derivation-helpers.ts

@@ -1,71 +0,0 @@
-export interface OutputInfo {
-  path: string;
-  hashAlgo: string;
-  hash: string;
-}
-
-export interface DerivationData {
-  name: string;
-  outputs: Map<string, OutputInfo>;
-  inputDrvs: Map<string, Set<string>>;
-  inputSrcs: Set<string>;
-  platform: string;
-  builder: string;
-  args: string[];
-  env: Map<string, string>;
-}
-
-export const escapeString = (s: string): string => {
-  let result = "";
-  for (const char of s) {
-    switch (char) {
-      case '"':
-        result += '\\"';
-        break;
-      case "\\":
-        result += "\\\\";
-        break;
-      case "\n":
-        result += "\\n";
-        break;
-      case "\r":
-        result += "\\r";
-        break;
-      case "\t":
-        result += "\\t";
-        break;
-      default:
-        result += char;
-    }
-  }
-  return `"${result}"`;
-};
-
-const quoteString = (s: string): string => `"${s}"`;
-
-export const generateAterm = (drv: DerivationData): string => {
-  const outputEntries: string[] = [];
-  const sortedOutputs = Array.from(drv.outputs.entries()).sort();
-  for (const [name, info] of sortedOutputs) {
-    outputEntries.push(
-      `(${quoteString(name)},${quoteString(info.path)},${quoteString(info.hashAlgo)},${quoteString(info.hash)})`,
-    );
-  }
-  const outputs = outputEntries.join(",");
-
-  const inputDrvEntries: string[] = [];
-  for (const [drvPath, outputs] of drv.inputDrvs) {
-    const outList = `[${Array.from(outputs).map(quoteString).join(",")}]`;
-    inputDrvEntries.push(`(${quoteString(drvPath)},${outList})`);
-  }
-  const inputDrvs = inputDrvEntries.join(",");
-
-  const inputSrcs = Array.from(drv.inputSrcs).map(quoteString).join(",");
-
-  const args = drv.args.map(escapeString).join(",");
-  const envs = Array.from(drv.env.entries())
-    .sort()
-    .map(([k, v]) => `(${escapeString(k)},${escapeString(v)})`);
-
-  return `Derive([${outputs}],[${inputDrvs}],[${inputSrcs}],${quoteString(drv.platform)},${quoteString(drv.builder)},[${args}],[${envs}])`;
-};

nix-js/runtime-ts/src/helpers.ts

@@ -1,18 +1,14 @@
-/**
- * Helper functions for nix-js runtime
- */
-
-import type { NixValue, NixAttrs, NixBool, NixString, NixPath } from "./types";
-import { forceAttrs, forceBool, forceFunction, forceStringValue } from "./type-assert";
-import { isAttrs, typeOf } from "./builtins/type-check";
 import { coerceToString, StringCoercionMode } from "./builtins/conversion";
-import { type NixStringContext, mkStringWithContext, isStringWithContext } from "./string-context";
-import { force } from "./thunk";
+import { isAttrs, typeOf } from "./builtins/type-check";
 import { mkPath } from "./path";
+import { isStringWithContext, mkStringWithContext, type NixStringContext } from "./string-context";
+import { force } from "./thunk";
+import { forceAttrs, forceBool, forceFunction, forceStringNoCtx, forceStringValue } from "./type-assert";
+import type { NixAttrs, NixBool, NixPath, NixString, NixValue } from "./types";
 import { CatchableError, isNixPath } from "./types";
 
 interface StackFrame {
-  span: string;
+  span: number;
   message: string;
 }
 
@@ -36,35 +32,18 @@ function enrichError(error: unknown): Error {
   return err;
 }
 
-export const getTos = (): string => {
-  const tos = callStack[callStack.length - 2];
-  const { file, line, column } = Deno.core.ops.op_decode_span(tos.span);
-  return `${tos.message} at ${file}:${line}:${column}`;
-}
-
-/**
- * Push an error context onto the stack
- * Used for tracking evaluation context (e.g., "while evaluating the condition")
- */
-export const pushContext = (message: string, span: string): void => {
+const pushContext = (message: string, span: number): void => {
   if (callStack.length >= MAX_STACK_DEPTH) {
     callStack.shift();
   }
   callStack.push({ span, message });
 };
 
-/**
- * Pop an error context from the stack
- */
-export const popContext = (): void => {
+const popContext = (): void => {
   callStack.pop();
 };
 
-/**
- * Execute a function with error context tracking
- * Automatically pushes context before execution and pops after
- */
-export const withContext = <T>(message: string, span: string, fn: () => T): T => {
+export const withContext = <T>(message: string, span: number, fn: () => T): T => {
   pushContext(message, span);
   try {
     return fn();
@@ -84,23 +63,20 @@ export const withContext = <T>(message: string, span: string, fn: () => T): T =>
  * - Path mode: Store contexts are forbidden (will throw error)
  * - String mode: All contexts are preserved and merged
  *
- * If first element is a path, result is a path (with constraint: no store context allowed)
- *
  * @param parts - Array of values to concatenate
+ * @param forceString - If true, result is always a string (paths are copied to store)
  * @returns String or Path with merged contexts from all parts
  */
-export const concatStringsWithContext = (parts: NixValue[]): NixString | NixPath => {
+export const concatStringsWithContext = (parts: NixValue[], forceString: boolean): NixString | NixPath => {
   if (parts.length === 0) {
     return "";
   }
 
   const forced = parts.map(force);
 
-  // Check if first element is a path
-  const firstIsPath = isNixPath(forced[0]);
+  const firstIsPath = !forceString && isNixPath(forced[0]);
 
   if (firstIsPath) {
-    // Path concatenation mode: result will be a path
     let result = (forced[0] as NixPath).value;
 
     for (let i = 1; i < forced.length; i++) {
@@ -111,13 +87,11 @@ export const concatStringsWithContext = (parts: NixValue[]): NixString | NixPath
       } else if (typeof part === "string") {
         result += part;
       } else if (isStringWithContext(part)) {
-        // Lix constraint: cannot mix store context with paths
         if (part.context.size > 0) {
           throw new TypeError("a string that refers to a store path cannot be appended to a path");
         }
         result += part.value;
       } else {
-        // Coerce to string
         const tempContext: NixStringContext = new Set();
         const coerced = coerceToString(part, StringCoercionMode.Interpolation, false, tempContext);
 
@@ -132,19 +106,15 @@ export const concatStringsWithContext = (parts: NixValue[]): NixString | NixPath
     return mkPath(result);
   }
 
-  // String concatenation mode
-  // Note: firstIsPath is already false at this point, otherwise we would have
-  // returned in the path concatenation branch above
   const context: NixStringContext = new Set();
   const strParts: string[] = [];
 
-  for (const part of parts) {
-    const forced = force(part);
-    if (isNixPath(forced)) {
-      const str = coerceToString(forced, StringCoercionMode.Interpolation, true, context);
+  for (const part of forced) {
+    if (isNixPath(part)) {
+      const str = coerceToString(part, StringCoercionMode.Interpolation, true, context);
       strParts.push(str);
     } else {
-      const str = coerceToString(forced, StringCoercionMode.Interpolation, false, context);
+      const str = coerceToString(part, StringCoercionMode.Interpolation, false, context);
       strParts.push(str);
     }
   }
@@ -158,13 +128,6 @@ export const concatStringsWithContext = (parts: NixValue[]): NixString | NixPath
   return mkStringWithContext(value, context);
 };
 
-/**
- * Resolve a path (handles both absolute and relative paths)
- * For relative paths, resolves against current import stack
- *
- * @param path - Path string (may be relative or absolute)
- * @returns NixPath object with absolute path
- */
 export const resolvePath = (currentDir: string, path: NixValue): NixPath => {
   const forced = force(path);
   let pathStr: string;
@@ -179,86 +142,92 @@ export const resolvePath = (currentDir: string, path: NixValue): NixPath => {
   return mkPath(resolved);
 };
 
-export const select = (obj: NixValue, attrpath: NixValue[], span?: string): NixValue => {
-  if (span) {
-    const pathStrings = attrpath.map((a) => forceStringValue(a));
-    const path = pathStrings.join(".");
-    const message = path ? `while selecting attribute [${path}]` : "while selecting attribute";
-
+export const select = (obj: NixValue, attrpath: NixValue[], span?: number): NixValue => {
+  if (span !== undefined) {
     if (callStack.length >= MAX_STACK_DEPTH) {
       callStack.shift();
     }
-    callStack.push({ span, message });
+    const frame: StackFrame = { span, message: "while selecting attribute" };
+    callStack.push(frame);
     try {
-      return select_impl(obj, attrpath);
+      return selectImpl(obj, attrpath);
     } catch (error) {
+      try {
+        const path = attrpath.map((a) => forceStringValue(a)).join(".");
+        if (path) frame.message = `while selecting attribute [${path}]`;
+      } catch {
+        throw enrichError(error);
+      }
       throw enrichError(error);
     } finally {
       callStack.pop();
     }
   } else {
-    return select_impl(obj, attrpath);
+    return selectImpl(obj, attrpath);
   }
 };
 
-function select_impl(obj: NixValue, attrpath: NixValue[]): NixValue {
+function selectImpl(obj: NixValue, attrpath: NixValue[]): NixValue {
   let attrs = forceAttrs(obj);
 
-  for (const attr of attrpath.slice(0, -1)) {
-    const key = forceStringValue(attr);
-    if (!(key in attrs)) {
+  for (let i = 0; i < attrpath.length - 1; i++) {
+    const key = forceStringValue(attrpath[i]);
+    if (!attrs.has(key)) {
       throw new Error(`Attribute '${key}' not found`);
     }
-    const cur = forceAttrs(attrs[forceStringValue(attr)]);
+    const cur = forceAttrs(attrs.get(key) as NixValue);
     attrs = cur;
   }
 
   const last = forceStringValue(attrpath[attrpath.length - 1]);
-  if (!(last in attrs)) {
+  if (!attrs.has(last)) {
     throw new Error(`Attribute '${last}' not found`);
   }
-  return attrs[last];
+  return attrs.get(last) as NixValue;
 }
 
 export const selectWithDefault = (
   obj: NixValue,
   attrpath: NixValue[],
-  default_val: NixValue,
-  span?: string,
+  defaultVal: NixValue,
+  span?: number,
 ): NixValue => {
-  if (span) {
-    const pathStrings = attrpath.map((a) => forceStringValue(a));
-    const path = pathStrings.join(".");
-    const message = path ? `while selecting attribute [${path}]` : "while selecting attribute";
-
+  if (span !== undefined) {
     if (callStack.length >= MAX_STACK_DEPTH) {
       callStack.shift();
     }
-    callStack.push({ span, message });
+    const frame: StackFrame = { span, message: "while selecting attribute" };
+    callStack.push(frame);
     try {
-      return selectWithDefault_impl(obj, attrpath, default_val);
+      return selectWithDefaultImpl(obj, attrpath, defaultVal);
     } catch (error) {
+      try {
+        const path = attrpath.map((a) => forceStringValue(a)).join(".");
+        if (path) frame.message = `while selecting attribute [${path}]`;
+      } catch {
+        throw enrichError(error);
+      }
       throw enrichError(error);
     } finally {
       callStack.pop();
     }
   } else {
-    return selectWithDefault_impl(obj, attrpath, default_val);
+    return selectWithDefaultImpl(obj, attrpath, defaultVal);
   }
 };
 
-function selectWithDefault_impl(obj: NixValue, attrpath: NixValue[], defaultVal: NixValue): NixValue {
+function selectWithDefaultImpl(obj: NixValue, attrpath: NixValue[], defaultVal: NixValue): NixValue {
   let attrs = force(obj);
   if (!isAttrs(attrs)) {
     return defaultVal;
   }
 
-  for (const attr of attrpath.slice(0, -1)) {
-    const key = forceStringValue(attr);
-    if (!(key in attrs)) {
+  for (let i = 0; i < attrpath.length - 1; i++) {
+    const key = forceStringValue(attrpath[i]);
+    if (!attrs.has(key)) {
       return defaultVal;
     }
-    const cur = force(attrs[key]);
+    const cur = force(attrs.get(key) as NixValue);
     if (!isAttrs(cur)) {
       return defaultVal;
     }
@@ -266,8 +235,8 @@ function selectWithDefault_impl(obj: NixValue, attrpath: NixValue[], defaultVal:
   }
 
   const last = forceStringValue(attrpath[attrpath.length - 1]);
-  if (last in attrs) {
-    return attrs[last];
+  if (attrs.has(last)) {
+    return attrs.get(last) as NixValue;
   }
   return defaultVal;
 }
@@ -279,97 +248,53 @@ export const hasAttr = (obj: NixValue, attrpath: NixValue[]): NixBool => {
   }
   let attrs = forced;
 
-  for (const attr of attrpath.slice(0, -1)) {
-    const cur = force(attrs[forceStringValue(attr)]);
+  for (let i = 0; i < attrpath.length - 1; i++) {
+    const key = forceStringNoCtx(attrpath[i]);
+    if (!attrs.has(key)) {
+      return false;
+    }
+    const cur = force(attrs.get(key) as NixValue);
     if (!isAttrs(cur)) {
       return false;
     }
     attrs = cur;
   }
 
-  return forceStringValue(attrpath[attrpath.length - 1]) in attrs;
+  return attrs.has(forceStringValue(attrpath[attrpath.length - 1]));
 };
 
-/**
- * Validate function parameters
- * Used for pattern matching in function parameters
- *
- * Example: { a, b ? 1, ... }: ...
- * - required: ["a"]
- * - allowed: ["a", "b"] (or null if ellipsis "..." present)
- *
- * @param arg - Argument object to validate
- * @param required - Array of required parameter names (or null)
- * @param allowed - Array of allowed parameter names (or null for ellipsis)
- * @returns The forced argument object
- * @throws Error if required param missing or unexpected param present
- */
-export const validateParams = (
-  arg: NixValue,
-  required: string[] | null,
-  allowed: string[] | null,
-): NixAttrs => {
-  const forced_arg = forceAttrs(arg);
-
-  // Check required parameters
-  if (required) {
-    for (const key of required) {
-      if (!Object.hasOwn(forced_arg, key)) {
-        throw new Error(`Function called without required argument '${key}'`);
-      }
-    }
-  }
-
-  // Check allowed parameters (if not using ellipsis)
-  if (allowed) {
-    const allowed_set = new Set(allowed);
-    for (const key in forced_arg) {
-      if (!allowed_set.has(key)) {
-        throw new Error(`Function called with unexpected argument '${key}'`);
-      }
-    }
-  }
-
-  return forced_arg;
-};
-
-export const call = (func: NixValue, arg: NixValue, span?: string): NixValue => {
-  if (span) {
+export const call = (func: NixValue, arg: NixValue, span?: number): NixValue => {
+  if (span !== undefined) {
     if (callStack.length >= MAX_STACK_DEPTH) {
       callStack.shift();
     }
     callStack.push({ span, message: "from call site" });
     try {
-      return call_impl(func, arg);
+      return callImpl(func, arg);
     } catch (error) {
       throw enrichError(error);
     } finally {
       callStack.pop();
     }
   } else {
-    return call_impl(func, arg);
+    return callImpl(func, arg);
   }
 };
 
-function call_impl(func: NixValue, arg: NixValue): NixValue {
-  const forcedFunc = force(func);
-  if (typeof forcedFunc === "function") {
-    forcedFunc.args?.check(arg);
-    return forcedFunc(arg);
+function callImpl(func: NixValue, arg: NixValue): NixValue {
+  const forced = force(func);
+  if (typeof forced === "function") {
+    forced.args?.check(arg);
+    return forced(arg);
   }
-  if (
-    typeof forcedFunc === "object" &&
-    !Array.isArray(forcedFunc) &&
-    forcedFunc !== null &&
-    "__functor" in forcedFunc
-  ) {
-    const functor = forceFunction(forcedFunc.__functor);
-    return call(functor(forcedFunc), arg);
+  if (forced instanceof Map && forced.has("__functor")) {
+    const functor = forceFunction(forced.get("__functor") as NixValue);
+    return call(callImpl(functor, forced), arg);
   }
-  throw new Error(`attempt to call something which is not a function but ${typeOf(forcedFunc)}`);
+  throw new Error(`attempt to call something which is not a function but ${typeOf(forced)}`);
 }
 
-export const assert = (assertion: NixValue, expr: NixValue, assertionRaw: string, span: string): NixValue => {
+export const assert = (assertion: NixValue, expr: NixValue, assertionRaw: string, span: number): NixValue => {
   if (forceBool(assertion)) {
     return expr;
   }
@@ -379,13 +304,23 @@ export const assert = (assertion: NixValue, expr: NixValue, assertionRaw: string
   throw "unreachable";
 };
 
-export const ifFunc = (cond: NixValue, consq: NixValue, alter: NixValue) => {
-  if (forceBool(cond)) {
-    return consq;
-  }
-  return alter;
-};
-
-export const mkPos = (span: string): NixAttrs => {
+export const mkPos = (span: number): NixAttrs => {
   return Deno.core.ops.op_decode_span(span);
 };
+
+interface WithScope {
+  env: NixValue;
+  last: WithScope | null;
+}
+
+export const lookupWith = (name: string, withScope: WithScope): NixValue => {
+  let current: WithScope | null = withScope;
+  while (current !== null) {
+    const attrs = forceAttrs(current.env);
+    if (attrs.has(name)) {
+      return attrs.get(name) as NixValue;
+    }
+    current = current.last;
+  }
+  throw new Error(`undefined variable '${name}'`);
+};

nix-js/runtime-ts/src/index.ts

@@ -4,68 +4,95 @@
  * All functionality is exported via the global `Nix` object
  */
 
-import { createThunk, force, isThunk, IS_THUNK, DEBUG_THUNKS, forceDeepSafe, IS_CYCLE } from "./thunk";
+import { builtins, PRIMOP_METADATA } from "./builtins";
 import {
+  assert,
+  call,
+  concatStringsWithContext,
+  hasAttr,
+  lookupWith,
+  mkPos,
+  resolvePath,
   select,
   selectWithDefault,
-  validateParams,
-  resolvePath,
-  hasAttr,
-  concatStringsWithContext,
-  call,
-  assert,
-  pushContext,
-  popContext,
-  withContext,
-  mkPos,
 } from "./helpers";
 import { op } from "./operators";
-import { builtins, PRIMOP_METADATA } from "./builtins";
-import { coerceToString, StringCoercionMode } from "./builtins/conversion";
 import { HAS_CONTEXT } from "./string-context";
-import { IS_PATH, mkAttrs, mkFunction, mkAttrsWithPos, ATTR_POSITIONS } from "./types";
+import { createThunk, DEBUG_THUNKS, force, forceDeep, forceShallow, IS_CYCLE, IS_THUNK } from "./thunk";
 import { forceBool } from "./type-assert";
+import { IS_PATH, mkAttrs, mkFunction, type NixValue } from "./types";
+import { execBytecode, execBytecodeScoped, vmStrings, vmConstants } from "./vm";
 
 export type NixRuntime = typeof Nix;
 
-/**
- * The global Nix runtime object
- */
+const replBindings: Map<string, NixValue> = new Map();
+
 export const Nix = {
-  createThunk,
-  force,
-  forceDeepSafe,
-  forceBool,
-  isThunk,
   IS_THUNK,
   IS_CYCLE,
   HAS_CONTEXT,
   IS_PATH,
+  PRIMOP_METADATA,
   DEBUG_THUNKS,
 
+  createThunk,
+  force,
+  forceBool,
+  forceShallow,
+  forceDeep,
+
   assert,
   call,
   hasAttr,
   select,
   selectWithDefault,
-  validateParams,
+  lookupWith,
   resolvePath,
-  coerceToString,
   concatStringsWithContext,
-  StringCoercionMode,
   mkAttrs,
-  mkAttrsWithPos,
   mkFunction,
   mkPos,
-  ATTR_POSITIONS,
-
-  pushContext,
-  popContext,
-  withContext,
 
   op,
   builtins,
-  PRIMOP_METADATA,
+
+  strings: vmStrings,
+  constants: vmConstants,
+  execBytecode,
+  execBytecodeScoped,
+
+  replBindings,
+  setReplBinding: (name: string, value: NixValue) => {
+    replBindings.set(name, value);
+  },
+  getReplBinding: (name: string) => replBindings.get(name),
 };
 
 globalThis.Nix = Nix;
+globalThis.$t = createThunk;
+globalThis.$f = force;
+globalThis.$fb = forceBool;
+globalThis.$a = assert;
+globalThis.$c = call;
+globalThis.$h = hasAttr;
+globalThis.$s = select;
+globalThis.$sd = selectWithDefault;
+globalThis.$l = lookupWith;
+globalThis.$r = resolvePath;
+globalThis.$cs = concatStringsWithContext;
+globalThis.$ma = mkAttrs;
+globalThis.$mf = mkFunction;
+globalThis.$mp = mkPos;
+globalThis.$gb = Nix.getReplBinding;
+
+globalThis.$oa = op.add;
+globalThis.$os = op.sub;
+globalThis.$om = op.mul;
+globalThis.$od = op.div;
+globalThis.$oe = op.eq;
+globalThis.$ol = op.lt;
+globalThis.$og = op.gt;
+globalThis.$oc = op.concat;
+globalThis.$ou = op.update;
+globalThis.$b = builtins;
+globalThis.$e = new Map();

nix-js/runtime-ts/src/operators.ts

@@ -1,31 +1,27 @@
-/**
- * Nix operators module
- * Implements all binary and unary operators used by codegen
- */
-
-import type { NixValue, NixList, NixAttrs, NixString, NixPath } from "./types";
-import { isNixPath } from "./types";
-import { force } from "./thunk";
-import { forceNumeric, forceList, forceAttrs, coerceNumeric } from "./type-assert";
-import { getStringValue, getStringContext, mergeContexts, mkStringWithContext } from "./string-context";
 import { coerceToString, StringCoercionMode } from "./builtins/conversion";
+import { isNixString, typeOf } from "./builtins/type-check";
 import { mkPath } from "./path";
-import { typeOf, isNixString } from "./builtins/type-check";
+import {
+  getStringContext,
+  getStringValue,
+  mergeContexts,
+  mkStringWithContext,
+  type NixStringContext,
+} from "./string-context";
+import { force } from "./thunk";
+import { coerceNumeric, forceAttrs, forceBool, forceList, forceNumeric } from "./type-assert";
+import type { NixAttrs, NixList, NixPath, NixString, NixValue } from "./types";
+import { isNixPath } from "./types";
 
 const canCoerceToString = (v: NixValue): boolean => {
   const forced = force(v);
   if (isNixString(forced)) return true;
-  if (typeof forced === "object" && forced !== null && !Array.isArray(forced)) {
-    if ("outPath" in forced || "__toString" in forced) return true;
+  if (forced instanceof Map) {
+    if (forced.has("outPath") || forced.has("__toString")) return true;
   }
   return false;
 };
 
-/**
- * Compare two values, similar to Nix's CompareValues.
- * Returns: -1 if a < b, 0 if a == b, 1 if a > b
- * Throws TypeError for incomparable types.
- */
 export const compareValues = (a: NixValue, b: NixValue): -1 | 0 | 1 => {
   const av = force(a);
   const bv = force(b);
@@ -48,32 +44,29 @@ export const compareValues = (a: NixValue, b: NixValue): -1 | 0 | 1 => {
     throw new TypeError(`cannot compare ${typeOf(av)} with ${typeOf(bv)}`);
   }
 
-  // Int and float comparison
   if (typeA === "int" || typeA === "float") {
-    return av! < bv! ? -1 : av === bv ? 0 : 1;
+    return (av as never) < (bv as never) ? -1 : av === bv ? 0 : 1;
   }
 
-  // String comparison (handles both plain strings and StringWithContext)
   if (typeA === "string") {
     const strA = getStringValue(av as NixString);
     const strB = getStringValue(bv as NixString);
     return strA < strB ? -1 : strA > strB ? 1 : 0;
   }
 
-  // Path comparison
   if (typeA === "path") {
     const aPath = av as NixPath;
     const bPath = bv as NixPath;
     return aPath.value < bPath.value ? -1 : aPath.value > bPath.value ? 1 : 0;
   }
 
-  // List comparison (lexicographic)
   if (typeA === "list") {
     const aList = av as NixList;
     const bList = bv as NixList;
     for (let i = 0; ; i++) {
+      // Equal if same length, else aList > bList
       if (i === bList.length) {
-        return i === aList.length ? 0 : 1; // Equal if same length, else aList > bList
+        return i === aList.length ? 0 : 1;
       } else if (i === aList.length) {
         return -1; // aList < bList
       } else if (!op.eq(aList[i], bList[i])) {
@@ -88,10 +81,6 @@ export const compareValues = (a: NixValue, b: NixValue): -1 | 0 | 1 => {
   );
 };
 
-/**
- * Operator object exported as Nix.op
- * All operators referenced by codegen (e.g., Nix.op.add, Nix.op.eq)
- */
 export const op = {
   add: (a: NixValue, b: NixValue): bigint | number | NixString | NixPath => {
     const av = force(a);
@@ -103,15 +92,14 @@ export const op = {
         const strB = getStringValue(bv);
         const ctxB = getStringContext(bv);
 
-        // Lix constraint: cannot append string with store context to path
         if (ctxB.size > 0) {
           throw new TypeError("a string that refers to a store path cannot be appended to a path");
         }
 
-        // Concatenate paths
         return mkPath(av.value + strB);
       }
 
+      // FIXME: handle corepkgs
       // path + path: concatenate
       if (isNixPath(bv)) {
         return mkPath(av.value + bv.value);
@@ -132,6 +120,7 @@ export const op = {
 
     // String concatenation
     if (isNixString(av) && isNixString(bv)) {
+      // Merge string context
       const strA = getStringValue(av);
       const strB = getStringValue(bv);
       const ctxA = getStringContext(av);
@@ -146,24 +135,29 @@ export const op = {
 
     // Auto-coerce to string if possible
     if (canCoerceToString(a) && canCoerceToString(b)) {
-      const strA = coerceToString(a, StringCoercionMode.Interpolation, false);
-      const strB = coerceToString(b, StringCoercionMode.Interpolation, false);
-      return strA + strB;
+      const context: NixStringContext = new Set();
+      const strA = coerceToString(a, StringCoercionMode.Interpolation, false, context);
+      const strB = coerceToString(b, StringCoercionMode.Interpolation, false, context);
+      const result = strA + strB;
+      if (context.size === 0) {
+        return result;
+      }
+      return mkStringWithContext(result, context);
     }
 
-    // Numeric addition
+    // Perform numeric addition otherwise
     const [numA, numB] = coerceNumeric(forceNumeric(a), forceNumeric(b));
-    return (numA as any) + (numB as any);
+    return (numA as never) + (numB as never);
   },
 
   sub: (a: NixValue, b: NixValue): bigint | number => {
     const [av, bv] = coerceNumeric(forceNumeric(a), forceNumeric(b));
-    return (av as any) - (bv as any);
+    return (av as never) - (bv as never);
   },
 
   mul: (a: NixValue, b: NixValue): bigint | number => {
     const [av, bv] = coerceNumeric(forceNumeric(a), forceNumeric(b));
-    return (av as any) * (bv as any);
+    return (av as never) * (bv as never);
   },
 
   div: (a: NixValue, b: NixValue): bigint | number => {
@@ -173,7 +167,7 @@ export const op = {
       throw new RangeError("Division by zero");
     }
 
-    return (av as any) / (bv as any);
+    return (av as never) / (bv as never);
   },
 
   eq: (a: NixValue, b: NixValue): boolean => {
@@ -191,7 +185,6 @@ export const op = {
       return av === Number(bv);
     }
 
-    // Get type names for comparison (skip if already handled above)
     const typeA = typeOf(av);
     const typeB = typeOf(bv);
 
@@ -212,10 +205,12 @@ export const op = {
       return (av as NixPath).value === (bv as NixPath).value;
     }
 
-    if (Array.isArray(av) && Array.isArray(bv)) {
-      if (av.length !== bv.length) return false;
-      for (let i = 0; i < av.length; i++) {
-        if (!op.eq(av[i], bv[i])) return false;
+    if (typeA === "list") {
+      const aList = av as NixList;
+      const bList = bv as NixList;
+      if (aList.length !== bList.length) return false;
+      for (let i = 0; i < aList.length; i++) {
+        if (!op.eq(aList[i], bList[i])) return false;
       }
       return true;
     }
@@ -224,37 +219,30 @@ export const op = {
       const attrsA = av as NixAttrs;
       const attrsB = bv as NixAttrs;
 
-      // Derivation comparison: compare outPaths only
-      // Safe to force 'type' because it's always a string literal, never a computed value
-      if ("type" in attrsA && "type" in attrsB) {
-        const typeValA = force(attrsA.type);
-        const typeValB = force(attrsB.type);
+      if (attrsA.has("type") && attrsB.has("type")) {
+        const typeValA = force(attrsA.get("type") as NixValue);
+        const typeValB = force(attrsB.get("type") as NixValue);
         if (typeValA === "derivation" && typeValB === "derivation") {
-          if ("outPath" in attrsA && "outPath" in attrsB) {
-            return op.eq(attrsA.outPath, attrsB.outPath);
+          if (attrsA.has("outPath") && attrsB.has("outPath")) {
+            return op.eq(attrsA.get("outPath") as NixValue, attrsB.get("outPath") as NixValue);
           }
         }
       }
 
-      // Otherwise, compare attributes one by one
-      const keysA = Object.keys(attrsA).sort();
-      const keysB = Object.keys(attrsB).sort();
+      const keysA = Array.from(attrsA.keys()).sort();
+      const keysB = Array.from(attrsB.keys()).sort();
 
       if (keysA.length !== keysB.length) return false;
 
       for (let i = 0; i < keysA.length; i++) {
         if (keysA[i] !== keysB[i]) return false;
-        if (!op.eq(attrsA[keysA[i]], attrsB[keysB[i]])) return false;
+        if (!op.eq(attrsA.get(keysA[i]) as NixValue, attrsB.get(keysB[i]) as NixValue)) return false;
       }
 
       return true;
     }
 
-    // Functions are incomparable
-    if (typeof av === "function") {
-      return false;
-    }
-
+    // Other types are incomparable
     return false;
   },
   neq: (a: NixValue, b: NixValue): boolean => {
@@ -273,11 +261,25 @@ export const op = {
     return compareValues(a, b) >= 0;
   },
 
-  bnot: (a: NixValue): boolean => !force(a),
+  bnot: (a: NixValue): boolean => !forceBool(a),
 
   concat: (a: NixValue, b: NixValue): NixList => {
-    return Array.prototype.concat.call(forceList(a), forceList(b));
+    return forceList(a).concat(forceList(b));
   },
 
-  update: (a: NixValue, b: NixValue): NixAttrs => ({ ...forceAttrs(a), ...forceAttrs(b) }),
+  update: (a: NixValue, b: NixValue): NixAttrs => {
+    const mapA = forceAttrs(a);
+    const mapB = forceAttrs(b);
+    if (mapA.size === 0) {
+      return mapB;
+    }
+    if (mapB.size === 0) {
+      return mapA;
+    }
+    const result: NixAttrs = new Map(mapA);
+    for (const [k, v] of mapB) {
+      result.set(k, v);
+    }
+    return result;
+  },
 };

nix-js/runtime-ts/src/path.ts

@@ -1,7 +1,36 @@
-import { IS_PATH, type NixPath } from "./types";
+import { NixPath } from "./types";
+
+const canonicalizePath = (path: string): string => {
+  const parts: string[] = [];
+  let i = 0;
+  const len = path.length;
+
+  while (i < len) {
+    while (i < len && path[i] === "/") i++;
+    if (i >= len) break;
+
+    let j = i;
+    while (j < len && path[j] !== "/") j++;
+    const component = path.slice(i, j);
+    i = j;
+
+    if (component === "..") {
+      if (parts.length > 0) {
+        parts.pop();
+      }
+    } else if (component !== ".") {
+      parts.push(component);
+    }
+  }
+
+  if (parts.length === 0) {
+    return "/";
+  }
+  return `/${parts.join("/")}`;
+};
 
 export const mkPath = (value: string): NixPath => {
-  return { [IS_PATH]: true, value };
+  return new NixPath(canonicalizePath(value));
 };
 
 export const getPathValue = (p: NixPath): string => {

nix-js/runtime-ts/src/print.ts

@@ -0,0 +1,111 @@
+import { getPrimopMetadata, isPrimop } from "./builtins/index";
+import { isStringWithContext } from "./string-context";
+import { IS_CYCLE, isThunk } from "./thunk";
+import { isNixPath, type NixValue } from "./types";
+
+export const printValue = (value: NixValue, seen: WeakSet<object> = new WeakSet()): string => {
+  if (isThunk(value)) {
+    return "«thunk»";
+  }
+
+  if (value === null) {
+    return "null";
+  }
+
+  if (typeof value === "boolean") {
+    return value ? "true" : "false";
+  }
+
+  if (typeof value === "bigint") {
+    return value.toString();
+  }
+
+  if (typeof value === "number") {
+    return value.toString();
+  }
+
+  if (typeof value === "string") {
+    return printString(value);
+  }
+
+  if (typeof value === "function") {
+    if (isPrimop(value)) {
+      const meta = getPrimopMetadata(value);
+      if (meta && meta.applied > 0) {
+        return "<PRIMOP-APP>";
+      }
+      return "<PRIMOP>";
+    }
+    return "<LAMBDA>";
+  }
+
+  if (IS_CYCLE in value) {
+    return "«repeated»";
+  }
+
+  if (isNixPath(value)) {
+    return value.value;
+  }
+
+  if (isStringWithContext(value)) {
+    return printString(value.value);
+  }
+
+  if (Array.isArray(value)) {
+    if (value.length > 0) {
+      if (seen.has(value)) {
+        return "«repeated»";
+      }
+      seen.add(value);
+    }
+    const items = value.map((v) => printValue(v, seen)).join(" ");
+    return `[ ${items} ]`;
+  }
+
+  if (seen.has(value)) {
+    return "«repeated»";
+  }
+  if (value.size > 0) {
+    seen.add(value);
+  }
+
+  const entries = [...value.entries()]
+    .map(([k, v]) => `${printSymbol(k)} = ${printValue(v, seen)};`)
+    .join(" ");
+  return `{${entries ? ` ${entries} ` : " "}}`;
+};
+
+const printString = (s: string): string => {
+  let result = '"';
+  for (const c of s) {
+    switch (c) {
+      case "\\":
+        result += "\\\\";
+        break;
+      case '"':
+        result += '\\"';
+        break;
+      case "\n":
+        result += "\\n";
+        break;
+      case "\r":
+        result += "\\r";
+        break;
+      case "\t":
+        result += "\\t";
+        break;
+      default:
+        result += c;
+    }
+  }
+  return `${result}"`;
+};
+
+const SYMBOL_REGEX = /^[a-zA-Z_][a-zA-Z0-9_'-]*$/;
+
+const printSymbol = (s: string): string => {
+  if (SYMBOL_REGEX.test(s)) {
+    return s;
+  }
+  return printString(s);
+};

nix-js/runtime-ts/src/string-context.ts

@@ -1,29 +1,4 @@
-/**
- * String Context System for Nix
- *
- * String context tracks references to store paths and derivations within strings.
- * This is critical for Nix's dependency tracking - when a string containing a
- * store path is used in a derivation, that store path becomes a build dependency.
- *
- * Context Elements (encoded as strings):
- * - Opaque: Plain store path reference
- *   Format: "/nix/store/..."
- *   Example: "/nix/store/abc123-hello"
- *
- * - DrvDeep: Derivation with all outputs
- *   Format: "=/nix/store/...drv"
- *   Example: "=/nix/store/xyz789-hello.drv"
- *   Meaning: All outputs of this derivation and its closure
- *
- * - Built: Specific derivation output
- *   Format: "!<output>!/nix/store/...drv"
- *   Example: "!out!/nix/store/xyz789-hello.drv"
- *   Meaning: Specific output (e.g., "out", "dev", "lib") of this derivation
- *
- * This implementation matches Lix's NixStringContext system.
- */
-
-import { NixStrictValue } from "./types";
+import type { NixStrictValue } from "./types";
 
 export const HAS_CONTEXT = Symbol("HAS_CONTEXT");
 
@@ -47,18 +22,22 @@ export type StringContextElem = StringContextOpaque | StringContextDrvDeep | Str
 
 export type NixStringContext = Set<string>;
 
-export interface StringWithContext {
-  readonly [HAS_CONTEXT]: true;
+export class StringWithContext {
+  readonly [HAS_CONTEXT] = true as const;
   value: string;
   context: NixStringContext;
+  constructor(value: string, context: NixStringContext) {
+    this.value = value;
+    this.context = context;
+  }
 }
 
 export const isStringWithContext = (v: NixStrictValue): v is StringWithContext => {
-  return typeof v === "object" && v !== null && HAS_CONTEXT in v;
+  return v instanceof StringWithContext;
 };
 
 export const mkStringWithContext = (value: string, context: NixStringContext): StringWithContext => {
-  return { [HAS_CONTEXT]: true, value, context };
+  return new StringWithContext(value, context);
 };
 
 export const mkPlainString = (value: string): string => value;
@@ -70,11 +49,12 @@ export const getStringValue = (s: string | StringWithContext): string => {
   return s;
 };
 
+const emptyContext: NixStringContext = new Set();
 export const getStringContext = (s: string | StringWithContext): NixStringContext => {
   if (isStringWithContext(s)) {
     return s.context;
   }
-  return new Set();
+  return emptyContext;
 };
 
 export const mergeContexts = (...contexts: NixStringContext[]): NixStringContext => {
@@ -165,49 +145,9 @@ export const parseContextToInfoMap = (context: NixStringContext): Map<string, Pa
     }
   }
 
+  for (const info of result.values()) {
+    info.outputs.sort();
+  }
+
   return result;
 };
-
-/**
- * Extract input derivations and source paths from context
- *
- * IMPORTANT: Used by derivation builder to determine build dependencies.
- *
- * Returns:
- * - inputDrvs: Map of derivation paths to their required output names
- * - inputSrcs: Set of plain store paths (opaque) and drvDeep references
- *
- * Context type handling:
- * - Opaque: Added to inputSrcs
- * - DrvDeep: Added to inputSrcs (entire derivation + all outputs)
- * - Built: Added to inputDrvs with specific output name
- */
-export const extractInputDrvsAndSrcs = (
-  context: NixStringContext,
-): { inputDrvs: Map<string, Set<string>>; inputSrcs: Set<string> } => {
-  const inputDrvs = new Map<string, Set<string>>();
-  const inputSrcs = new Set<string>();
-
-  for (const encoded of context) {
-    const elem = decodeContextElem(encoded);
-    switch (elem.type) {
-      case "opaque":
-        inputSrcs.add(elem.path);
-        break;
-      case "drvDeep":
-        inputSrcs.add(elem.drvPath);
-        break;
-      case "built": {
-        let outputs = inputDrvs.get(elem.drvPath);
-        if (!outputs) {
-          outputs = new Set<string>();
-          inputDrvs.set(elem.drvPath, outputs);
-        }
-        outputs.add(elem.output);
-        break;
-      }
-    }
-  }
-
-  return { inputDrvs, inputSrcs };
-};

nix-js/runtime-ts/src/thunk.ts

@@ -1,16 +1,8 @@
-/**
- * Lazy evaluation system for nix-js
- * Implements thunks for lazy evaluation of Nix expressions
- */
+import { isAttrs, isList } from "./builtins/type-check";
+import { StringWithContext } from "./string-context";
+import type { NixAttrs, NixStrictValue, NixValue } from "./types";
+import { NixPath } from "./types";
 
-import type { NixValue, NixThunkInterface, NixStrictValue } from "./types";
-import { HAS_CONTEXT } from "./string-context";
-import { IS_PATH } from "./types";
-
-/**
- * Symbol used to mark objects as thunks
- * This is exported to Rust via Nix.IS_THUNK
- */
 export const IS_THUNK = Symbol("is_thunk");
 
 const forceStack: NixThunk[] = [];
@@ -29,8 +21,7 @@ export const DEBUG_THUNKS = { enabled: true };
  * - Evaluating (blackhole): func is undefined, result is undefined
  * - Evaluated: func is undefined, result is defined
  */
-export class NixThunk implements NixThunkInterface {
-  [key: symbol]: any;
+export class NixThunk {
   readonly [IS_THUNK] = true as const;
   func: (() => NixValue) | undefined;
   result: NixStrictValue | undefined;
@@ -50,13 +41,8 @@ export class NixThunk implements NixThunkInterface {
   }
 }
 
-/**
- * Type guard to check if a value is a thunk
- * @param value - Value to check
- * @returns true if value is a NixThunk
- */
-export const isThunk = (value: unknown): value is NixThunkInterface => {
-  return value !== null && typeof value === "object" && IS_THUNK in value && value[IS_THUNK] === true;
+export const isThunk = (value: NixValue): value is NixThunk => {
+  return value instanceof NixThunk;
 };
 
 /**
@@ -95,7 +81,7 @@ export const force = (value: NixValue): NixStrictValue => {
   }
 
   const thunk = value as NixThunk;
-  const func = thunk.func!;
+  const func = thunk.func as () => NixValue;
   thunk.func = undefined;
 
   if (DEBUG_THUNKS.enabled) {
@@ -125,33 +111,20 @@ export const force = (value: NixValue): NixStrictValue => {
   }
 };
 
-/**
- * Create a new thunk from a function
- * @param func - Function that produces a value when called
- * @param label - Optional label for debugging
- * @returns A new NixThunk wrapping the function
- */
-export const createThunk = (func: () => NixValue, label?: string): NixThunkInterface => {
+export const createThunk = (func: () => NixValue, label?: string): NixThunk => {
   return new NixThunk(func, label);
 };
 
-/**
- * Symbol to mark cyclic references detected during deep forcing
- */
 export const IS_CYCLE = Symbol("is_cycle");
-
-/**
- * Marker object for cyclic references
- */
-export const CYCLE_MARKER = { [IS_CYCLE]: true };
+export const CYCLE_MARKER = { [IS_CYCLE]: true as const };
 
 /**
  * Deeply force a value, handling cycles by returning a special marker.
  * Uses WeakSet to track seen objects and avoid infinite recursion.
  * Returns a fully forced value where thunks are replaced with their results.
- * Cyclic references are replaced with CYCLE_MARKER.
+ * Cyclic references are replaced with CYCLE_MARKER, preserving the container type.
  */
-export const forceDeepSafe = (value: NixValue, seen: WeakSet<object> = new WeakSet()): NixStrictValue => {
+export const forceDeep = (value: NixValue, seen: WeakSet<object> = new WeakSet()): NixStrictValue => {
   const forced = force(value);
 
   if (forced === null || typeof forced !== "object") {
@@ -161,20 +134,52 @@ export const forceDeepSafe = (value: NixValue, seen: WeakSet<object> = new WeakS
   if (seen.has(forced)) {
     return CYCLE_MARKER;
   }
+  if ((isAttrs(forced) && forced.size > 0) || (isList(forced) && forced.length > 0)) {
     seen.add(forced);
+  }
 
-  if (HAS_CONTEXT in forced || IS_PATH in forced) {
+  if (forced instanceof StringWithContext || forced instanceof NixPath) {
     return forced;
   }
 
   if (Array.isArray(forced)) {
-    return forced.map((item) => forceDeepSafe(item, seen));
+    return forced.map((item) => forceDeep(item, seen));
   }
 
-  if (typeof forced === "object") {
-    const result: Record<string, NixValue> = {};
-    for (const [key, val] of Object.entries(forced)) {
-      result[key] = forceDeepSafe(val, seen);
+  if (forced instanceof Map) {
+    const result: NixAttrs = new Map();
+    for (const [key, val] of forced) {
+      result.set(key, forceDeep(val, seen));
+    }
+    return result;
+  }
+
+  return forced;
+};
+
+export const forceShallow = (value: NixValue): NixStrictValue => {
+  const forced = force(value);
+
+  if (forced === null || typeof forced !== "object") {
+    return forced;
+  }
+
+  if (Array.isArray(forced)) {
+    return forced.map((item) => {
+      const forcedItem = force(item);
+      if (typeof forcedItem === "object" && forcedItem === forced) {
+        return CYCLE_MARKER;
+      } else {
+        return forcedItem;
+      }
+    });
+  }
+
+  if (isAttrs(forced)) {
+    const result: NixAttrs = new Map();
+    for (const [key, val] of forced) {
+      const forcedVal = force(val as NixValue);
+      result.set(key, forcedVal === forced ? CYCLE_MARKER : forcedVal);
     }
     return result;
   }

nix-js/runtime-ts/src/type-assert.ts

@@ -1,28 +1,18 @@
-/**
- * Type assertion helpers for runtime type checking
- * These functions force evaluation and verify the type, throwing errors on mismatch
- */
-
+import { isAttrs, isFunction, typeOf } from "./builtins/type-check";
+import { force } from "./thunk";
 import type {
-  NixValue,
-  NixList,
   NixAttrs,
+  NixFloat,
   NixFunction,
   NixInt,
-  NixFloat,
+  NixList,
   NixNumber,
-  NixString,
   NixPath,
+  NixString,
+  NixValue,
 } from "./types";
-import { isStringWithContext, isNixPath } from "./types";
-import { force } from "./thunk";
-import { getStringValue } from "./string-context";
-import { isAttrs, isFunction, typeOf } from "./builtins/type-check";
+import { isNixPath, isStringWithContext } from "./types";
 
-/**
- * Force a value and assert it's a list
- * @throws TypeError if value is not a list after forcing
- */
 export const forceList = (value: NixValue): NixList => {
   const forced = force(value);
   if (!Array.isArray(forced)) {
@@ -31,22 +21,19 @@ export const forceList = (value: NixValue): NixList => {
   return forced;
 };
 
-/**
- * Force a value and assert it's a function
- * @throws TypeError if value is not a function after forcing
- */
 export const forceFunction = (value: NixValue): NixFunction => {
   const forced = force(value);
-  if (!isFunction(forced)) {
-    throw new TypeError(`Expected function, got ${typeOf(forced)}`);
-  }
+  if (isFunction(forced)) {
     return forced;
+  }
+  if (forced instanceof Map && forced.has("__functor")) {
+    const functorSet = forced as NixAttrs;
+    const functor = forceFunction(functorSet.get("__functor") as NixValue);
+    return (arg: NixValue) => forceFunction(functor(functorSet))(arg);
+  }
+  throw new TypeError(`Expected function, got ${typeOf(forced)}`);
 };
 
-/**
- * Force a value and assert it's an attribute set
- * @throws TypeError if value is not an attribute set after forcing
- */
 export const forceAttrs = (value: NixValue): NixAttrs => {
   const forced = force(value);
   if (!isAttrs(forced)) {
@@ -55,10 +42,6 @@ export const forceAttrs = (value: NixValue): NixAttrs => {
   return forced;
 };
 
-/**
- * Force a value and assert it's a string (plain or with context)
- * @throws TypeError if value is not a string after forcing
- */
 export const forceStringValue = (value: NixValue): string => {
   const forced = force(value);
   if (typeof forced === "string") {
@@ -70,10 +53,6 @@ export const forceStringValue = (value: NixValue): string => {
   throw new TypeError(`Expected string, got ${typeOf(forced)}`);
 };
 
-/**
- * Force a value and assert it's a string, returning NixString (preserving context)
- * @throws TypeError if value is not a string after forcing
- */
 export const forceString = (value: NixValue): NixString => {
   const forced = force(value);
   if (typeof forced === "string") {
@@ -91,15 +70,11 @@ export const forceStringNoCtx = (value: NixValue): string => {
     return forced;
   }
   if (isStringWithContext(forced)) {
-    throw new TypeError(`the string '${forced.value}' is not allowed to refer to a store path`)
+    throw new TypeError(`the string '${forced.value}' is not allowed to refer to a store path`);
   }
   throw new TypeError(`Expected string, got ${typeOf(forced)}`);
-}
+};
 
-/**
- * Force a value and assert it's a boolean
- * @throws TypeError if value is not a boolean after forcing
- */
 export const forceBool = (value: NixValue): boolean => {
   const forced = force(value);
   if (typeof forced !== "boolean") {
@@ -108,10 +83,6 @@ export const forceBool = (value: NixValue): boolean => {
   return forced;
 };
 
-/**
- * Force a value and extract int value
- * @throws TypeError if value is not an int
- */
 export const forceInt = (value: NixValue): NixInt => {
   const forced = force(value);
   if (typeof forced === "bigint") {
@@ -120,10 +91,6 @@ export const forceInt = (value: NixValue): NixInt => {
   throw new TypeError(`Expected int, got ${typeOf(forced)}`);
 };
 
-/**
- * Force a value and extract float value
- * @throws TypeError if value is not a float
- */
 export const forceFloat = (value: NixValue): NixFloat => {
   const forced = force(value);
   if (typeof forced === "number") {
@@ -132,10 +99,6 @@ export const forceFloat = (value: NixValue): NixFloat => {
   throw new TypeError(`Expected float, got ${typeOf(forced)}`);
 };
 
-/**
- * Force a value and extract numeric value (int or float)
- * @throws TypeError if value is not a numeric type
- */
 export const forceNumeric = (value: NixValue): NixNumber => {
   const forced = force(value);
   if (typeof forced === "bigint" || typeof forced === "number") {
@@ -144,28 +107,17 @@ export const forceNumeric = (value: NixValue): NixNumber => {
   throw new TypeError(`Expected numeric type, got ${typeOf(forced)}`);
 };
 
-/**
- * Coerce two numeric values to a common type for arithmetic
- * Rule: If either is float, convert both to float; otherwise keep as bigint
- * @returns [a, b] tuple of coerced values
- */
 export const coerceNumeric = (a: NixNumber, b: NixNumber): [NixFloat, NixFloat] | [NixInt, NixInt] => {
   const aIsInt = typeof a === "bigint";
   const bIsInt = typeof b === "bigint";
 
-  // If either is float, convert both to float
   if (!aIsInt || !bIsInt) {
     return [Number(a), Number(b)];
   }
 
-  // Both are integers
   return [a, b];
 };
 
-/**
- * Force a value and assert it's a path
- * @throws TypeError if value is not a path after forcing
- */
 export const forceNixPath = (value: NixValue): NixPath => {
   const forced = force(value);
   if (isNixPath(forced)) {

nix-js/runtime-ts/src/types.ts

@@ -1,27 +1,24 @@
-/**
- * Core TypeScript type definitions for nix-js runtime
- */
-
-import { force, IS_THUNK } from "./thunk";
-import { type StringWithContext, HAS_CONTEXT, isStringWithContext, getStringContext } from "./string-context";
-import { op } from "./operators";
+import { PRIMOP_METADATA, type PrimopMetadata } from "./builtins";
+import { HAS_CONTEXT, isStringWithContext, type StringWithContext } from "./string-context";
+import { type CYCLE_MARKER, force, type NixThunk } from "./thunk";
 import { forceAttrs, forceStringNoCtx } from "./type-assert";
-import { isString, typeOf } from "./builtins/type-check";
 export { HAS_CONTEXT, isStringWithContext };
 export type { StringWithContext };
 
 export const IS_PATH = Symbol("IS_PATH");
 
-export interface NixPath {
-  readonly [IS_PATH]: true;
+export class NixPath {
+  readonly [IS_PATH] = true as const;
   value: string;
+  constructor(value: string) {
+    this.value = value;
+  }
 }
 
 export const isNixPath = (v: NixStrictValue): v is NixPath => {
-  return typeof v === "object" && v !== null && IS_PATH in v;
+  return v instanceof NixPath;
 };
 
-// Nix primitive types
 export type NixInt = bigint;
 export type NixFloat = number;
 export type NixNumber = NixInt | NixFloat;
@@ -29,19 +26,23 @@ export type NixBool = boolean;
 export type NixString = string | StringWithContext;
 export type NixNull = null;
 
-// Nix composite types
+export const ATTR_POSITIONS = Symbol("attrPositions");
 export type NixList = NixValue[];
-// FIXME: reject contextful string
-export type NixAttrs = { [key: string]: NixValue };
-export type NixFunction = ((arg: NixValue) => NixValue) & { args?: NixArgs };
+export type NixAttrs = Map<string, NixValue> & { [ATTR_POSITIONS]?: Map<string, number> };
+export type NixFunction = ((arg: NixValue) => NixValue) & {
+  args?: NixArgs;
+  [PRIMOP_METADATA]?: PrimopMetadata;
+};
 export class NixArgs {
   required: string[];
   optional: string[];
   allowed: Set<string>;
   ellipsis: boolean;
-  constructor(required: string[], optional: string[], ellipsis: boolean) {
+  positions: Map<string, number>;
+  constructor(required: string[], optional: string[], positions: Map<string, number>, ellipsis: boolean) {
     this.required = required;
     this.optional = optional;
+    this.positions = positions;
     this.ellipsis = ellipsis;
     this.allowed = new Set(required.concat(optional));
   }
@@ -49,13 +50,13 @@ export class NixArgs {
     const attrs = forceAttrs(arg);
 
     for (const key of this.required) {
-      if (!Object.hasOwn(attrs, key)) {
+      if (!attrs.has(key)) {
         throw new Error(`Function called without required argument '${key}'`);
       }
     }
 
     if (!this.ellipsis) {
-      for (const key in attrs) {
+      for (const key of attrs.keys()) {
         if (!this.allowed.has(key)) {
           throw new Error(`Function called with unexpected argument '${key}'`);
         }
@@ -67,32 +68,18 @@ export const mkFunction = (
   f: (arg: NixValue) => NixValue,
   required: string[],
   optional: string[],
+  positions: Map<string, number>,
   ellipsis: boolean,
 ): NixFunction => {
-  const func = f as NixFunction;
-  func.args = new NixArgs(required, optional, ellipsis);
+  const func: NixFunction = f;
+  func.args = new NixArgs(required, optional, positions, ellipsis);
   return func;
 };
 
-export const mkAttrs = (attrs: NixAttrs, keys: NixValue[], values: NixValue[]): NixAttrs => {
-  const len = keys.length;
-  for (let i = 0; i < len; i++) {
-    const key = force(keys[i]);
-    if (key === null) {
-      continue;
-    }
-    const str = forceStringNoCtx(key);
-    attrs[str] = values[i];
-  }
-  return attrs;
-};
-
-const ATTR_POSITIONS = Symbol("attrPositions");
-
-export const mkAttrsWithPos = (
+export const mkAttrs = (
   attrs: NixAttrs,
-  positions: Record<string, string>,
-  dyns?: { dynKeys: NixValue[]; dynVals: NixValue[]; dynSpans: string[] }
+  positions: Map<string, number>,
+  dyns?: { dynKeys: NixValue[]; dynVals: NixValue[]; dynSpans: number[] },
 ): NixAttrs => {
   if (dyns) {
     const len = dyns.dynKeys.length;
@@ -102,62 +89,27 @@ export const mkAttrsWithPos = (
         continue;
       }
       const str = forceStringNoCtx(key);
-      attrs[str] = dyns.dynVals[i];
-      positions[str] = dyns.dynSpans[i];
+      attrs.set(str, dyns.dynVals[i]);
+      positions.set(str, dyns.dynSpans[i]);
     }
   }
 
-  if (Object.keys(positions).length > 0) {
-    Object.defineProperty(attrs, ATTR_POSITIONS, {
-      value: positions,
-      enumerable: false,
-      writable: false,
-    });
+  if (positions.size > 0) {
+    attrs[ATTR_POSITIONS] = positions;
   }
 
   return attrs;
 };
 
-export { ATTR_POSITIONS };
-
-/**
- * Interface for lazy thunk values
- * Thunks delay evaluation until forced
- */
-export interface NixThunkInterface {
-  readonly [IS_THUNK]: true;
-  func: (() => NixValue) | undefined;
-  result: NixStrictValue | undefined;
-}
-
-// Union of all Nix primitive types
 export type NixPrimitive = NixNull | NixBool | NixInt | NixFloat | NixString;
+export type NixValue =
+  | NixPrimitive
+  | NixPath
+  | NixList
+  | NixAttrs
+  | NixFunction
+  | NixThunk
+  | typeof CYCLE_MARKER;
+export type NixStrictValue = Exclude<NixValue, NixThunk>;
 
-/**
- * NixValue: Union type representing any possible Nix value
- * This is the core type used throughout the runtime
- */
-export type NixValue = NixPrimitive | NixPath | NixList | NixAttrs | NixFunction | NixThunkInterface;
-
-export type NixStrictValue = Exclude<NixValue, NixThunkInterface>;
-
-/**
- * CatchableError: Error type thrown by `builtins.throw`
- * This can be caught by `builtins.tryEval`
- */
 export class CatchableError extends Error {}
-
-// Operator function signatures
-export type BinaryOp<T = NixValue, U = NixValue, R = NixValue> = (a: T, b: U) => R;
-export type UnaryOp<T = NixValue, R = NixValue> = (a: T) => R;
-
-/**
- * Curried function types - All Nix builtins must be curried!
- *
- * Examples:
- * - add: Curried2<number, number, number> = (a) => (b) => a + b
- * - map: Curried2<NixFunction, NixList, NixList> = (f) => (list) => list.map(f)
- */
-export type Curried2<A, B, R> = (a: A) => (b: B) => R;
-export type Curried3<A, B, C, R> = (a: A) => (b: B) => (c: C) => R;
-export type Curried4<A, B, C, D, R> = (a: A) => (b: B) => (c: C) => (d: D) => R;

nix-js/runtime-ts/src/types/global.d.ts

@@ -1,67 +1,123 @@
 import type { NixRuntime } from "..";
-
-interface FetchUrlResult {
-  store_path: string;
-  hash: string;
-}
-
-interface FetchTarballResult {
-  store_path: string;
-  hash: string;
-  nar_hash: string;
-}
-
-interface FetchGitResult {
-  out_path: string;
-  rev: string;
-  short_rev: string;
-  rev_count: number;
-  last_modified: number;
-  last_modified_date: string;
-  submodules: boolean;
-  nar_hash: string | null;
-}
-
-interface FetchHgResult {
-  out_path: string;
-  branch: string;
-  rev: string;
-  short_rev: string;
-  rev_count: number;
-}
+import type { builtins } from "../builtins";
+import type { FetchGitResult, FetchTarballResult, FetchUrlResult } from "../builtins/io";
+import type {
+  assert,
+  call,
+  concatStringsWithContext,
+  hasAttr,
+  lookupWith,
+  mkPos,
+  resolvePath,
+  select,
+  selectWithDefault,
+} from "../helpers";
+import type { op } from "../operators";
+import type { createThunk, force } from "../thunk";
+import type { forceBool } from "../type-assert";
+import type { mkAttrs, mkFunction, NixAttrs, NixStrictValue } from "../types";
 
 declare global {
   var Nix: NixRuntime;
+  var $t: typeof createThunk;
+  var $f: typeof force;
+  var $fb: typeof forceBool;
+  var $a: typeof assert;
+  var $c: typeof call;
+  var $h: typeof hasAttr;
+  var $s: typeof select;
+  var $sd: typeof selectWithDefault;
+  var $l: typeof lookupWith;
+  var $r: typeof resolvePath;
+  var $cs: typeof concatStringsWithContext;
+  var $ma: typeof mkAttrs;
+  var $mf: typeof mkFunction;
+  var $mp: typeof mkPos;
+  var $oa: typeof op.add;
+  var $os: typeof op.sub;
+  var $om: typeof op.mul;
+  var $od: typeof op.div;
+  var $oe: typeof op.eq;
+  var $ol: typeof op.lt;
+  var $og: typeof op.gt;
+  var $oc: typeof op.concat;
+  var $ou: typeof op.update;
+  var $b: typeof builtins;
+  var $e: NixAttrs;
+  var $gb: typeof Nix.getReplBinding;
+
   namespace Deno {
     namespace core {
       namespace ops {
+        function op_import(path: string): [Uint8Array, string];
+        function op_scoped_import(path: string, scopeKeys: string[]): [Uint8Array, string];
+
         function op_resolve_path(currentDir: string, path: string): string;
-        function op_import(path: string): string;
+
         function op_read_file(path: string): string;
         function op_read_file_type(path: string): string;
-        function op_read_dir(path: string): Record<string, string>;
+        function op_read_dir(path: string): Map<string, string>;
         function op_path_exists(path: string): boolean;
-        function op_sha256_hex(data: string): string;
-        function op_decode_span(span: string): { file: string | null; line: number | null; column: number | null };
-        function op_make_store_path(ty: string, hash_hex: string, name: string): string;
-        function op_output_path_name(drv_name: string, output_name: string): string;
-        function op_make_fixed_output_path(
-          hash_algo: string,
-          hash: string,
-          hash_mode: string,
-          name: string,
+        function op_walk_dir(path: string): [string, string][];
+
+        function op_make_placeholder(output: string): string;
+        function op_store_path(path: string): string;
+
+        function op_convert_hash(hash: string, hashAlgo: string | null, toHashFormat: string): string;
+        function op_hash_string(algo: string, data: string): string;
+        function op_hash_file(algo: string, path: string): string;
+        function op_parse_hash(hashStr: string, algo: string | null): { hex: string; algo: string };
+
+        function op_add_path(
+          path: string,
+          name: string | null,
+          recursive: boolean,
+          sha256: string | null,
         ): string;
+        function op_add_filtered_path(
+          path: string,
+          name: string | null,
+          recursive: boolean,
+          sha256: string | null,
+          includePaths: string[],
+        ): string;
+
+        function op_decode_span(span: number): NixAttrs;
+
+        function op_to_file(name: string, contents: string, references: string[]): string;
+
+        function op_copy_path_to_store(path: string): string;
+
+        function op_get_env(key: string): string;
+
+        function op_match(regex: string, text: string): (string | null)[] | null;
+        function op_split(regex: string, text: string): (string | (string | null)[])[];
+
+        function op_from_json(json: string): NixStrictValue;
+        function op_from_toml(toml: string): NixStrictValue;
+        function op_to_xml(e: NixValue): [string, string[]];
+
+        function op_finalize_derivation(
+          name: string,
+          builder: string,
+          platform: string,
+          outputs: string[],
+          args: string[],
+          env: [string, string][],
+          context: string[],
+          fixedOutput: { hashAlgo: string; hash: string; hashMode: string } | null,
+        ): { drvPath: string; outputs: [string, string][] };
+
         function op_fetch_url(
           url: string,
-          expected_hash: string | null,
+          expectedHash: string | null,
           name: string | null,
           executable: boolean,
         ): FetchUrlResult;
         function op_fetch_tarball(
           url: string,
-          expected_hash: string | null,
-          expected_nar_hash: string | null,
           name: string | null,
+          sha256: string | null,
         ): FetchTarballResult;
         function op_fetch_git(
           url: string,
@@ -69,20 +125,9 @@ declare global {
           rev: string | null,
           shallow: boolean,
           submodules: boolean,
-          all_refs: boolean,
+          allRefs: boolean,
           name: string | null,
         ): FetchGitResult;
-        function op_fetch_hg(url: string, rev: string | null, name: string | null): FetchHgResult;
-        function op_add_path(
-          path: string,
-          name: string | null,
-          recursive: boolean,
-          sha256: string | null,
-        ): string;
-        function op_store_path(path: string): string;
-        function op_to_file(name: string, contents: string, references: string[]): string;
-        function op_copy_path_to_store(path: string): string;
-        function op_get_env(key: string): string;
       }
     }
   }

nix-js/runtime-ts/src/vm.ts

@@ -0,0 +1,617 @@
+import {
+  assert,
+  call,
+  concatStringsWithContext,
+  hasAttr,
+  lookupWith,
+  mkPos,
+  resolvePath,
+  select,
+  selectWithDefault,
+} from "./helpers";
+import { op } from "./operators";
+import { NixThunk } from "./thunk";
+import { forceBool } from "./type-assert";
+import { mkAttrs, NixArgs, type NixAttrs, type NixFunction, type NixValue } from "./types";
+import { builtins } from "./builtins";
+
+enum Op {
+  PushConst = 0x01,
+  PushString = 0x02,
+  PushNull = 0x03,
+  PushTrue = 0x04,
+  PushFalse = 0x05,
+
+  LoadLocal = 0x06,
+  LoadOuter = 0x07,
+  StoreLocal = 0x08,
+  AllocLocals = 0x09,
+
+  MakeThunk = 0x0A,
+  MakeClosure = 0x0B,
+  MakePatternClosure = 0x0C,
+
+  Call = 0x0D,
+  CallNoSpan = 0x0E,
+
+  MakeAttrs = 0x0F,
+  MakeAttrsDyn = 0x10,
+  MakeEmptyAttrs = 0x11,
+  Select = 0x12,
+  SelectDefault = 0x13,
+  HasAttr = 0x14,
+
+  MakeList = 0x15,
+
+  OpAdd = 0x16,
+  OpSub = 0x17,
+  OpMul = 0x18,
+  OpDiv = 0x19,
+  OpEq = 0x20,
+  OpNeq = 0x21,
+  OpLt = 0x22,
+  OpGt = 0x23,
+  OpLeq = 0x24,
+  OpGeq = 0x25,
+  OpConcat = 0x26,
+  OpUpdate = 0x27,
+
+  OpNeg = 0x28,
+  OpNot = 0x29,
+
+  ForceBool = 0x30,
+  JumpIfFalse = 0x31,
+  JumpIfTrue = 0x32,
+  Jump = 0x33,
+
+  ConcatStrings = 0x34,
+  ResolvePath = 0x35,
+
+  Assert = 0x36,
+
+  PushWith = 0x37,
+  PopWith = 0x38,
+  WithLookup = 0x39,
+
+  LoadBuiltins = 0x40,
+  LoadBuiltin = 0x41,
+
+  MkPos = 0x43,
+
+  LoadReplBinding = 0x44,
+  LoadScopedBinding = 0x45,
+
+  Return = 0x46,
+}
+
+interface ScopeChain {
+  locals: NixValue[];
+  parent: ScopeChain | null;
+}
+
+interface WithScope {
+  env: NixValue;
+  last: WithScope | null;
+}
+
+const strings: string[] = [];
+const constants: NixValue[] = [];
+
+const $e: NixAttrs = new Map();
+
+function readU16(code: Uint8Array, offset: number): number {
+  return code[offset] | (code[offset + 1] << 8);
+}
+
+function readU32(code: Uint8Array, offset: number): number {
+  return (
+    code[offset] |
+    (code[offset + 1] << 8) |
+    (code[offset + 2] << 16) |
+    (code[offset + 3] << 24)
+  ) >>> 0;
+}
+
+function readI32(code: Uint8Array, offset: number): number {
+  return code[offset] | (code[offset + 1] << 8) | (code[offset + 2] << 16) | (code[offset + 3] << 24);
+}
+
+export function execBytecode(code: Uint8Array, currentDir: string): NixValue {
+  const chain: ScopeChain = { locals: [], parent: null };
+  return execFrame(code, 0, chain, currentDir, null, null);
+}
+
+export function execBytecodeScoped(
+  code: Uint8Array,
+  currentDir: string,
+  scopeMap: NixAttrs,
+): NixValue {
+  const chain: ScopeChain = { locals: [], parent: null };
+  return execFrame(code, 0, chain, currentDir, null, scopeMap);
+}
+
+function execFrame(
+  code: Uint8Array,
+  startPc: number,
+  chain: ScopeChain,
+  currentDir: string,
+  withScope: WithScope | null,
+  scopeMap: NixAttrs | null,
+): NixValue {
+  const locals = chain.locals;
+  const stack: NixValue[] = [];
+  let pc = startPc;
+
+  for (;;) {
+    const opcode = code[pc++];
+    switch (opcode) {
+      case Op.PushConst: {
+        const idx = readU32(code, pc);
+        pc += 4;
+        stack.push(constants[idx]);
+        break;
+      }
+      case Op.PushString: {
+        const idx = readU32(code, pc);
+        pc += 4;
+        stack.push(strings[idx]);
+        break;
+      }
+      case Op.PushNull:
+        stack.push(null);
+        break;
+      case Op.PushTrue:
+        stack.push(true);
+        break;
+      case Op.PushFalse:
+        stack.push(false);
+        break;
+
+      case Op.LoadLocal: {
+        const idx = readU32(code, pc);
+        pc += 4;
+        stack.push(locals[idx]);
+        break;
+      }
+      case Op.LoadOuter: {
+        const layer = code[pc++];
+        const idx = readU32(code, pc);
+        pc += 4;
+        let c: ScopeChain = chain;
+        for (let i = 0; i < layer; i++) c = c.parent!;
+        stack.push(c.locals[idx]);
+        break;
+      }
+      case Op.StoreLocal: {
+        const idx = readU32(code, pc);
+        pc += 4;
+        locals[idx] = stack.pop()!;
+        break;
+      }
+      case Op.AllocLocals: {
+        const n = readU32(code, pc);
+        pc += 4;
+        for (let i = 0; i < n; i++) locals.push(null);
+        break;
+      }
+
+      case Op.MakeThunk: {
+        const bodyPc = readU32(code, pc);
+        pc += 4;
+        const labelIdx = readU32(code, pc);
+        pc += 4;
+        const label = strings[labelIdx];
+        const scopeChain = chain;
+        const scopeCode = code;
+        const scopeDir = currentDir;
+        const scopeWith = withScope;
+        stack.push(
+          new NixThunk(
+            () => execFrame(scopeCode, bodyPc, scopeChain, scopeDir, scopeWith, null),
+            label,
+          ),
+        );
+        break;
+      }
+      case Op.MakeClosure: {
+        const bodyPc = readU32(code, pc);
+        pc += 4;
+        const nSlots = readU32(code, pc);
+        pc += 4;
+        const closureChain = chain;
+        const closureCode = code;
+        const closureDir = currentDir;
+        const closureWith = withScope;
+        const func: NixFunction = (arg: NixValue) => {
+          const innerLocals = new Array<NixValue>(1 + nSlots).fill(null);
+          innerLocals[0] = arg;
+          const innerChain: ScopeChain = { locals: innerLocals, parent: closureChain };
+          return execFrame(closureCode, bodyPc, innerChain, closureDir, closureWith, null);
+        };
+        stack.push(func);
+        break;
+      }
+      case Op.MakePatternClosure: {
+        const bodyPc = readU32(code, pc);
+        pc += 4;
+        const nSlots = readU32(code, pc);
+        pc += 4;
+        const nRequired = readU16(code, pc);
+        pc += 2;
+        const nOptional = readU16(code, pc);
+        pc += 2;
+        const hasEllipsis = code[pc++] !== 0;
+
+        const required: string[] = [];
+        for (let i = 0; i < nRequired; i++) {
+          required.push(strings[readU32(code, pc)]);
+          pc += 4;
+        }
+        const optional: string[] = [];
+        for (let i = 0; i < nOptional; i++) {
+          optional.push(strings[readU32(code, pc)]);
+          pc += 4;
+        }
+        const positions = new Map<string, number>();
+        const nTotal = nRequired + nOptional;
+        for (let i = 0; i < nTotal; i++) {
+          const nameIdx = readU32(code, pc);
+          pc += 4;
+          const spanId = readU32(code, pc);
+          pc += 4;
+          positions.set(strings[nameIdx], spanId);
+        }
+
+        const closureChain = chain;
+        const closureCode = code;
+        const closureDir = currentDir;
+        const closureWith = withScope;
+        const func: NixFunction = (arg: NixValue) => {
+          const innerLocals = new Array<NixValue>(1 + nSlots).fill(null);
+          innerLocals[0] = arg;
+          const innerChain: ScopeChain = { locals: innerLocals, parent: closureChain };
+          return execFrame(closureCode, bodyPc, innerChain, closureDir, closureWith, null);
+        };
+        func.args = new NixArgs(required, optional, positions, hasEllipsis);
+        stack.push(func);
+        break;
+      }
+
+      case Op.Call: {
+        const spanId = readU32(code, pc);
+        pc += 4;
+        const arg = stack.pop()!;
+        const func = stack.pop()!;
+        stack.push(call(func, arg, spanId));
+        break;
+      }
+      case Op.CallNoSpan: {
+        const arg = stack.pop()!;
+        const func = stack.pop()!;
+        stack.push(call(func, arg));
+        break;
+      }
+
+      case Op.MakeAttrs: {
+        const n = readU32(code, pc);
+        pc += 4;
+        const spanValues: number[] = [];
+        for (let i = 0; i < n; i++) {
+          spanValues.push(stack.pop() as number);
+        }
+        spanValues.reverse();
+        const map: NixAttrs = new Map();
+        const posMap = new Map<string, number>();
+        const pairs: [string, NixValue][] = [];
+        for (let i = 0; i < n; i++) {
+          const val = stack.pop()!;
+          const key = stack.pop() as string;
+          pairs.push([key, val]);
+        }
+        pairs.reverse();
+        for (let i = 0; i < n; i++) {
+          map.set(pairs[i][0], pairs[i][1]);
+          posMap.set(pairs[i][0], spanValues[i]);
+        }
+        stack.push(mkAttrs(map, posMap));
+        break;
+      }
+      case Op.MakeAttrsDyn: {
+        const nStatic = readU32(code, pc);
+        pc += 4;
+        const nDyn = readU32(code, pc);
+        pc += 4;
+
+        const dynTriples: [NixValue, NixValue, number][] = [];
+        for (let i = 0; i < nDyn; i++) {
+          const dynSpan = stack.pop() as number;
+          const dynVal = stack.pop()!;
+          const dynKey = stack.pop()!;
+          dynTriples.push([dynKey, dynVal, dynSpan]);
+        }
+        dynTriples.reverse();
+
+        const spanValues: number[] = [];
+        for (let i = 0; i < nStatic; i++) {
+          spanValues.push(stack.pop() as number);
+        }
+        spanValues.reverse();
+
+        const map: NixAttrs = new Map();
+        const posMap = new Map<string, number>();
+        const pairs: [string, NixValue][] = [];
+        for (let i = 0; i < nStatic; i++) {
+          const val = stack.pop()!;
+          const key = stack.pop() as string;
+          pairs.push([key, val]);
+        }
+        pairs.reverse();
+        for (let i = 0; i < nStatic; i++) {
+          map.set(pairs[i][0], pairs[i][1]);
+          posMap.set(pairs[i][0], spanValues[i]);
+        }
+
+        const dynKeys: NixValue[] = [];
+        const dynVals: NixValue[] = [];
+        const dynSpans: number[] = [];
+        for (const [k, v, s] of dynTriples) {
+          dynKeys.push(k);
+          dynVals.push(v);
+          dynSpans.push(s);
+        }
+
+        stack.push(mkAttrs(map, posMap, { dynKeys, dynVals, dynSpans }));
+        break;
+      }
+      case Op.MakeEmptyAttrs:
+        stack.push($e);
+        break;
+
+      case Op.Select: {
+        const nKeys = readU16(code, pc);
+        pc += 2;
+        const spanId = readU32(code, pc);
+        pc += 4;
+        const keys: NixValue[] = [];
+        for (let i = 0; i < nKeys; i++) keys.push(stack.pop()!);
+        keys.reverse();
+        const obj = stack.pop()!;
+        stack.push(select(obj, keys, spanId));
+        break;
+      }
+      case Op.SelectDefault: {
+        const nKeys = readU16(code, pc);
+        pc += 2;
+        const spanId = readU32(code, pc);
+        pc += 4;
+        const defaultVal = stack.pop()!;
+        const keys: NixValue[] = [];
+        for (let i = 0; i < nKeys; i++) keys.push(stack.pop()!);
+        keys.reverse();
+        const obj = stack.pop()!;
+        stack.push(selectWithDefault(obj, keys, defaultVal, spanId));
+        break;
+      }
+      case Op.HasAttr: {
+        const nKeys = readU16(code, pc);
+        pc += 2;
+        const keys: NixValue[] = [];
+        for (let i = 0; i < nKeys; i++) keys.push(stack.pop()!);
+        keys.reverse();
+        const obj = stack.pop()!;
+        stack.push(hasAttr(obj, keys));
+        break;
+      }
+
+      case Op.MakeList: {
+        const count = readU32(code, pc);
+        pc += 4;
+        const items: NixValue[] = new Array(count);
+        for (let i = count - 1; i >= 0; i--) {
+          items[i] = stack.pop()!;
+        }
+        stack.push(items);
+        break;
+      }
+
+      case Op.OpAdd: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(op.add(a, b));
+        break;
+      }
+      case Op.OpSub: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(op.sub(a, b));
+        break;
+      }
+      case Op.OpMul: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(op.mul(a, b));
+        break;
+      }
+      case Op.OpDiv: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(op.div(a, b));
+        break;
+      }
+      case Op.OpEq: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(op.eq(a, b));
+        break;
+      }
+      case Op.OpNeq: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(!op.eq(a, b));
+        break;
+      }
+      case Op.OpLt: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(op.lt(a, b));
+        break;
+      }
+      case Op.OpGt: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(op.gt(a, b));
+        break;
+      }
+      case Op.OpLeq: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(!op.gt(a, b));
+        break;
+      }
+      case Op.OpGeq: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(!op.lt(a, b));
+        break;
+      }
+      case Op.OpConcat: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(op.concat(a, b));
+        break;
+      }
+      case Op.OpUpdate: {
+        const b = stack.pop()!;
+        const a = stack.pop()!;
+        stack.push(op.update(a, b));
+        break;
+      }
+
+      case Op.OpNeg: {
+        const a = stack.pop()!;
+        stack.push(op.sub(0n, a));
+        break;
+      }
+      case Op.OpNot: {
+        const a = stack.pop()!;
+        stack.push(!forceBool(a));
+        break;
+      }
+
+      case Op.ForceBool: {
+        const val = stack.pop()!;
+        stack.push(forceBool(val));
+        break;
+      }
+      case Op.JumpIfFalse: {
+        const offset = readI32(code, pc);
+        pc += 4;
+        const val = stack.pop()!;
+        if (val === false) {
+          pc += offset;
+        }
+        break;
+      }
+      case Op.JumpIfTrue: {
+        const offset = readI32(code, pc);
+        pc += 4;
+        const val = stack.pop()!;
+        if (val === true) {
+          pc += offset;
+        }
+        break;
+      }
+      case Op.Jump: {
+        const offset = readI32(code, pc);
+        pc += 4;
+        pc += offset;
+        break;
+      }
+
+      case Op.ConcatStrings: {
+        const nParts = readU16(code, pc);
+        pc += 2;
+        const forceString = code[pc++] !== 0;
+        const parts: NixValue[] = new Array(nParts);
+        for (let i = nParts - 1; i >= 0; i--) {
+          parts[i] = stack.pop()!;
+        }
+        stack.push(concatStringsWithContext(parts, forceString));
+        break;
+      }
+      case Op.ResolvePath: {
+        const pathExpr = stack.pop()!;
+        stack.push(resolvePath(currentDir, pathExpr));
+        break;
+      }
+
+      case Op.Assert: {
+        const rawIdx = readU32(code, pc);
+        pc += 4;
+        const spanId = readU32(code, pc);
+        pc += 4;
+        const expr = stack.pop()!;
+        const assertion = stack.pop()!;
+        stack.push(assert(assertion, expr, strings[rawIdx], spanId));
+        break;
+      }
+
+      case Op.PushWith: {
+        const namespace = stack.pop()!;
+        withScope = { env: namespace, last: withScope };
+        break;
+      }
+      case Op.PopWith:
+        withScope = withScope!.last;
+        break;
+      case Op.WithLookup: {
+        const nameIdx = readU32(code, pc);
+        pc += 4;
+        stack.push(lookupWith(strings[nameIdx], withScope!));
+        break;
+      }
+
+      case Op.LoadBuiltins:
+        stack.push(builtins);
+        break;
+      case Op.LoadBuiltin: {
+        const idx = readU32(code, pc);
+        pc += 4;
+        stack.push(builtins.get(strings[idx])!);
+        break;
+      }
+
+      case Op.MkPos: {
+        const spanId = readU32(code, pc);
+        pc += 4;
+        stack.push(mkPos(spanId));
+        break;
+      }
+
+      case Op.LoadReplBinding: {
+        const idx = readU32(code, pc);
+        pc += 4;
+        stack.push(Nix.getReplBinding(strings[idx]));
+        break;
+      }
+      case Op.LoadScopedBinding: {
+        const idx = readU32(code, pc);
+        pc += 4;
+        stack.push(scopeMap!.get(strings[idx])!);
+        break;
+      }
+
+      case Op.Return:
+        return stack.pop()!;
+
+      default:
+        throw new Error(`Unknown bytecode opcode: ${opcode ? `0x${opcode.toString(16)}` : "undefined"} at pc=${pc - 1}`);
+    }
+  }
+}
+
+declare const Nix: {
+  getReplBinding: (name: string) => NixValue;
+};
+
+export { strings as vmStrings, constants as vmConstants };

nix-js/src/bin/eval.rs

@@ -1,26 +0,0 @@
-use anyhow::Result;
-use nix_js::{context::Context, error::Source};
-use std::process::exit;
-
-fn main() -> Result<()> {
-    nix_js::logging::init_logging();
-
-    let mut args = std::env::args();
-    if args.len() != 2 {
-        eprintln!("Usage: {} expr", args.next().unwrap());
-        exit(1);
-    }
-    args.next();
-    let expr = args.next().unwrap();
-    let src = Source::new_eval(expr)?;
-    match Context::new()?.eval_code(src) {
-        Ok(value) => {
-            println!("{value}");
-            Ok(())
-        }
-        Err(err) => {
-            eprintln!("{:?}", miette::Report::new(*err));
-            exit(1);
-        }
-    }
-}

nix-js/src/bin/repl.rs

@@ -1,56 +0,0 @@
-use anyhow::Result;
-use nix_js::context::Context;
-use nix_js::error::Source;
-use regex::Regex;
-use rustyline::DefaultEditor;
-use rustyline::error::ReadlineError;
-
-fn main() -> Result<()> {
-    nix_js::logging::init_logging();
-
-    let mut rl = DefaultEditor::new()?;
-    let mut context = Context::new()?;
-    let re = Regex::new(r"^\s*([a-zA-Z_][a-zA-Z0-9_'-]*)\s*=(.*)$").unwrap();
-    loop {
-        let readline = rl.readline("nix-js-repl> ");
-        match readline {
-            Ok(line) => {
-                if line.trim().is_empty() {
-                    continue;
-                }
-                let _ = rl.add_history_entry(line.as_str());
-                if let Some(_caps) = re.captures(&line) {
-                    eprintln!("Error: binding not implemented yet");
-                    continue;
-                    /* let ident = caps.get(1).unwrap().as_str();
-                    let expr = caps.get(2).unwrap().as_str().trim();
-                    if expr.is_empty() {
-                        eprintln!("Error: missing expression after '='");
-                        continue;
-                    }
-                    if let Err(err) = context.add_binding(ident, expr) {
-                        eprintln!("Error: {}", err);
-                    } */
-                } else {
-                    let src = Source::new_repl(line)?;
-                    match context.eval_code(src) {
-                        Ok(value) => println!("{value}"),
-                        Err(err) => eprintln!("{:?}", miette::Report::new(*err)),
-                    }
-                }
-            }
-            Err(ReadlineError::Interrupted) => {
-                println!();
-            }
-            Err(ReadlineError::Eof) => {
-                println!("CTRL-D");
-                break;
-            }
-            Err(err) => {
-                eprintln!("Error: {err:?}");
-                break;
-            }
-        }
-    }
-    Ok(())
-}

nix-js/src/bytecode.rs

@@ -0,0 +1,906 @@
+use std::ops::Deref;
+use std::path::Path;
+
+use hashbrown::HashMap;
+use num_enum::TryFromPrimitive;
+use rnix::TextRange;
+
+use crate::ir::{ArgId, Attr, BinOpKind, Ir, Param, RawIrRef, SymId, ThunkId, UnOpKind};
+
+#[derive(Clone, Hash, Eq, PartialEq)]
+pub(crate) enum Constant {
+    Int(i64),
+    Float(u64),
+}
+
+pub struct Bytecode {
+    pub code: Box<[u8]>,
+    pub current_dir: String,
+}
+
+pub(crate) trait BytecodeContext {
+    fn intern_string(&mut self, s: &str) -> u32;
+    fn intern_constant(&mut self, c: Constant) -> u32;
+    fn register_span(&self, range: TextRange) -> u32;
+    fn get_sym(&self, id: SymId) -> &str;
+    fn get_current_dir(&self) -> &Path;
+}
+
+#[repr(u8)]
+#[derive(Clone, Copy, TryFromPrimitive)]
+#[allow(clippy::enum_variant_names)]
+pub enum Op {
+    PushConst = 0x01,
+    PushString = 0x02,
+    PushNull = 0x03,
+    PushTrue = 0x04,
+    PushFalse = 0x05,
+
+    LoadLocal = 0x06,
+    LoadOuter = 0x07,
+    StoreLocal = 0x08,
+    AllocLocals = 0x09,
+
+    MakeThunk = 0x0A,
+    MakeClosure = 0x0B,
+    MakePatternClosure = 0x0C,
+
+    Call = 0x0D,
+    CallNoSpan = 0x0E,
+
+    MakeAttrs = 0x0F,
+    MakeAttrsDyn = 0x10,
+    MakeEmptyAttrs = 0x11,
+    Select = 0x12,
+    SelectDefault = 0x13,
+    HasAttr = 0x14,
+
+    MakeList = 0x15,
+
+    OpAdd = 0x16,
+    OpSub = 0x17,
+    OpMul = 0x18,
+    OpDiv = 0x19,
+    OpEq = 0x20,
+    OpNeq = 0x21,
+    OpLt = 0x22,
+    OpGt = 0x23,
+    OpLeq = 0x24,
+    OpGeq = 0x25,
+    OpConcat = 0x26,
+    OpUpdate = 0x27,
+
+    OpNeg = 0x28,
+    OpNot = 0x29,
+
+    ForceBool = 0x30,
+    JumpIfFalse = 0x31,
+    JumpIfTrue = 0x32,
+    Jump = 0x33,
+
+    ConcatStrings = 0x34,
+    ResolvePath = 0x35,
+
+    Assert = 0x36,
+
+    PushWith = 0x37,
+    PopWith = 0x38,
+    WithLookup = 0x39,
+
+    LoadBuiltins = 0x40,
+    LoadBuiltin = 0x41,
+
+    MkPos = 0x43,
+
+    LoadReplBinding = 0x44,
+    LoadScopedBinding = 0x45,
+
+    Return = 0x46,
+}
+
+struct ScopeInfo {
+    depth: u16,
+    arg_id: Option<ArgId>,
+    thunk_map: HashMap<ThunkId, u32>,
+}
+
+struct BytecodeEmitter<'a, Ctx: BytecodeContext> {
+    ctx: &'a mut Ctx,
+    code: Vec<u8>,
+    scope_stack: Vec<ScopeInfo>,
+}
+
+pub(crate) fn compile_bytecode(ir: RawIrRef<'_>, ctx: &mut impl BytecodeContext) -> Bytecode {
+    let current_dir = ctx.get_current_dir().to_string_lossy().to_string();
+    let mut emitter = BytecodeEmitter::new(ctx);
+    emitter.emit_toplevel(ir);
+    Bytecode {
+        code: emitter.code.into_boxed_slice(),
+        current_dir,
+    }
+}
+
+pub(crate) fn compile_bytecode_scoped(
+    ir: RawIrRef<'_>,
+    ctx: &mut impl BytecodeContext,
+) -> Bytecode {
+    let current_dir = ctx.get_current_dir().to_string_lossy().to_string();
+    let mut emitter = BytecodeEmitter::new(ctx);
+    emitter.emit_toplevel_scoped(ir);
+    Bytecode {
+        code: emitter.code.into_boxed_slice(),
+        current_dir,
+    }
+}
+
+impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
+    fn new(ctx: &'a mut Ctx) -> Self {
+        Self {
+            ctx,
+            code: Vec::with_capacity(4096),
+            scope_stack: Vec::with_capacity(32),
+        }
+    }
+
+    #[inline]
+    fn emit_op(&mut self, op: Op) {
+        self.code.push(op as u8);
+    }
+
+    #[inline]
+    fn emit_u8(&mut self, val: u8) {
+        self.code.push(val);
+    }
+
+    #[inline]
+    fn emit_u16(&mut self, val: u16) {
+        self.code.extend_from_slice(&val.to_le_bytes());
+    }
+
+    #[inline]
+    fn emit_u32(&mut self, val: u32) {
+        self.code.extend_from_slice(&val.to_le_bytes());
+    }
+
+    #[inline]
+    fn emit_i32_placeholder(&mut self) -> usize {
+        let offset = self.code.len();
+        self.code.extend_from_slice(&[0u8; 4]);
+        offset
+    }
+    #[inline]
+    fn patch_i32(&mut self, offset: usize, val: i32) {
+        self.code[offset..offset + 4].copy_from_slice(&val.to_le_bytes());
+    }
+
+    #[inline]
+    fn emit_jump_placeholder(&mut self) -> usize {
+        self.emit_op(Op::Jump);
+        self.emit_i32_placeholder()
+    }
+
+    #[inline]
+    fn patch_jump_target(&mut self, placeholder_offset: usize) {
+        let current_pos = self.code.len();
+        let relative_offset = (current_pos as i32) - (placeholder_offset as i32) - 4;
+        self.patch_i32(placeholder_offset, relative_offset);
+    }
+
+    fn current_depth(&self) -> u16 {
+        self.scope_stack.last().map_or(0, |s| s.depth)
+    }
+
+    fn resolve_thunk(&self, id: ThunkId) -> (u16, u32) {
+        for scope in self.scope_stack.iter().rev() {
+            if let Some(&local_idx) = scope.thunk_map.get(&id) {
+                let layer = self.current_depth() - scope.depth;
+                return (layer, local_idx);
+            }
+        }
+        panic!("ThunkId {:?} not found in any scope", id);
+    }
+
+    fn resolve_arg(&self, id: ArgId) -> (u16, u32) {
+        for scope in self.scope_stack.iter().rev() {
+            if scope.arg_id == Some(id) {
+                let layer = self.current_depth() - scope.depth;
+                return (layer, 0);
+            }
+        }
+        panic!("ArgId {:?} not found in any scope", id);
+    }
+
+    fn emit_load(&mut self, layer: u16, local: u32) {
+        if layer == 0 {
+            self.emit_op(Op::LoadLocal);
+            self.emit_u32(local);
+        } else {
+            self.emit_op(Op::LoadOuter);
+            self.emit_u8(layer as u8);
+            self.emit_u32(local);
+        }
+    }
+
+    fn count_with_thunks(&self, ir: RawIrRef<'_>) -> usize {
+        match ir.deref() {
+            Ir::With { thunks, body, .. } => thunks.len() + self.count_with_thunks(*body),
+            Ir::TopLevel { thunks, body } => thunks.len() + self.count_with_thunks(*body),
+            Ir::If { cond, consq, alter } => {
+                self.count_with_thunks(*cond)
+                    + self.count_with_thunks(*consq)
+                    + self.count_with_thunks(*alter)
+            }
+            Ir::BinOp { lhs, rhs, .. } => {
+                self.count_with_thunks(*lhs) + self.count_with_thunks(*rhs)
+            }
+            Ir::UnOp { rhs, .. } => self.count_with_thunks(*rhs),
+            Ir::Call { func, arg, .. } => {
+                self.count_with_thunks(*func) + self.count_with_thunks(*arg)
+            }
+            Ir::Assert {
+                assertion, expr, ..
+            } => self.count_with_thunks(*assertion) + self.count_with_thunks(*expr),
+            Ir::Select { expr, default, .. } => {
+                self.count_with_thunks(*expr) + default.map_or(0, |d| self.count_with_thunks(d))
+            }
+            Ir::HasAttr { lhs, .. } => self.count_with_thunks(*lhs),
+            Ir::ConcatStrings { parts, .. } => {
+                parts.iter().map(|p| self.count_with_thunks(*p)).sum()
+            }
+            Ir::Path(p) => self.count_with_thunks(*p),
+            Ir::List { items } => items.iter().map(|item| self.count_with_thunks(*item)).sum(),
+            Ir::AttrSet { stcs, dyns } => {
+                stcs.iter()
+                    .map(|(_, &(val, _))| self.count_with_thunks(val))
+                    .sum::<usize>()
+                    + dyns
+                        .iter()
+                        .map(|&(k, v, _)| self.count_with_thunks(k) + self.count_with_thunks(v))
+                        .sum::<usize>()
+            }
+            _ => 0,
+        }
+    }
+
+    fn collect_all_thunks<'ir>(
+        &self,
+        own_thunks: &[(ThunkId, RawIrRef<'ir>)],
+        body: RawIrRef<'ir>,
+    ) -> Vec<(ThunkId, RawIrRef<'ir>)> {
+        let mut all = Vec::from(own_thunks);
+        self.collect_with_thunks_recursive(body, &mut all);
+        let mut i = 0;
+        while i < all.len() {
+            let thunk_body = all[i].1;
+            self.collect_with_thunks_recursive(thunk_body, &mut all);
+            i += 1;
+        }
+        all
+    }
+
+    fn collect_with_thunks_recursive<'ir>(
+        &self,
+        ir: RawIrRef<'ir>,
+        out: &mut Vec<(ThunkId, RawIrRef<'ir>)>,
+    ) {
+        match ir.deref() {
+            Ir::With { thunks, body, .. } => {
+                for &(id, inner) in thunks.iter() {
+                    out.push((id, inner));
+                }
+                self.collect_with_thunks_recursive(*body, out);
+            }
+            Ir::TopLevel { thunks, body } => {
+                for &(id, inner) in thunks.iter() {
+                    out.push((id, inner));
+                }
+                self.collect_with_thunks_recursive(*body, out);
+            }
+            Ir::If { cond, consq, alter } => {
+                self.collect_with_thunks_recursive(*cond, out);
+                self.collect_with_thunks_recursive(*consq, out);
+                self.collect_with_thunks_recursive(*alter, out);
+            }
+            Ir::BinOp { lhs, rhs, .. } => {
+                self.collect_with_thunks_recursive(*lhs, out);
+                self.collect_with_thunks_recursive(*rhs, out);
+            }
+            Ir::UnOp { rhs, .. } => self.collect_with_thunks_recursive(*rhs, out),
+            Ir::Call { func, arg, .. } => {
+                self.collect_with_thunks_recursive(*func, out);
+                self.collect_with_thunks_recursive(*arg, out);
+            }
+            Ir::Assert {
+                assertion, expr, ..
+            } => {
+                self.collect_with_thunks_recursive(*assertion, out);
+                self.collect_with_thunks_recursive(*expr, out);
+            }
+            Ir::Select { expr, default, .. } => {
+                self.collect_with_thunks_recursive(*expr, out);
+                if let Some(d) = default {
+                    self.collect_with_thunks_recursive(*d, out);
+                }
+            }
+            Ir::HasAttr { lhs, .. } => self.collect_with_thunks_recursive(*lhs, out),
+            Ir::ConcatStrings { parts, .. } => {
+                for p in parts.iter() {
+                    self.collect_with_thunks_recursive(*p, out);
+                }
+            }
+            Ir::Path(p) => self.collect_with_thunks_recursive(*p, out),
+            Ir::List { items } => {
+                for item in items.iter() {
+                    self.collect_with_thunks_recursive(*item, out);
+                }
+            }
+            Ir::AttrSet { stcs, dyns } => {
+                for (_, &(val, _)) in stcs.iter() {
+                    self.collect_with_thunks_recursive(val, out);
+                }
+                for &(key, val, _) in dyns.iter() {
+                    self.collect_with_thunks_recursive(key, out);
+                    self.collect_with_thunks_recursive(val, out);
+                }
+            }
+            _ => {}
+        }
+    }
+
+    fn push_scope(&mut self, has_arg: bool, arg_id: Option<ArgId>, thunk_ids: &[ThunkId]) {
+        let depth = self.scope_stack.len() as u16;
+        let thunk_base = if has_arg { 1u32 } else { 0u32 };
+        let thunk_map = thunk_ids
+            .iter()
+            .enumerate()
+            .map(|(i, &id)| (id, thunk_base + i as u32))
+            .collect();
+        self.scope_stack.push(ScopeInfo {
+            depth,
+            arg_id,
+            thunk_map,
+        });
+    }
+
+    fn pop_scope(&mut self) {
+        self.scope_stack.pop();
+    }
+
+    fn emit_toplevel(&mut self, ir: RawIrRef<'_>) {
+        match ir.deref() {
+            Ir::TopLevel { body, thunks } => {
+                let with_thunk_count = self.count_with_thunks(*body);
+                let total_slots = thunks.len() + with_thunk_count;
+
+                let all_thunks = self.collect_all_thunks(thunks, *body);
+                let thunk_ids: Vec<ThunkId> = all_thunks.iter().map(|&(id, _)| id).collect();
+
+                self.push_scope(false, None, &thunk_ids);
+
+                if total_slots > 0 {
+                    self.emit_op(Op::AllocLocals);
+                    self.emit_u32(total_slots as u32);
+                }
+
+                self.emit_scope_thunks(thunks);
+                self.emit_expr(*body);
+                self.emit_op(Op::Return);
+
+                self.pop_scope();
+            }
+            _ => {
+                self.push_scope(false, None, &[]);
+                self.emit_expr(ir);
+                self.emit_op(Op::Return);
+                self.pop_scope();
+            }
+        }
+    }
+
+    fn emit_toplevel_scoped(&mut self, ir: RawIrRef<'_>) {
+        match ir.deref() {
+            Ir::TopLevel { body, thunks } => {
+                let with_thunk_count = self.count_with_thunks(*body);
+                let total_slots = thunks.len() + with_thunk_count;
+
+                let all_thunks = self.collect_all_thunks(thunks, *body);
+                let thunk_ids: Vec<ThunkId> = all_thunks.iter().map(|&(id, _)| id).collect();
+
+                self.push_scope(false, None, &thunk_ids);
+
+                if total_slots > 0 {
+                    self.emit_op(Op::AllocLocals);
+                    self.emit_u32(total_slots as u32);
+                }
+
+                self.emit_scope_thunks(thunks);
+                self.emit_expr(*body);
+                self.emit_op(Op::Return);
+
+                self.pop_scope();
+            }
+            _ => {
+                self.push_scope(false, None, &[]);
+                self.emit_expr(ir);
+                self.emit_op(Op::Return);
+                self.pop_scope();
+            }
+        }
+    }
+
+    fn emit_scope_thunks(&mut self, thunks: &[(ThunkId, RawIrRef<'_>)]) {
+        for &(id, inner) in thunks {
+            let label = format!("e{}", id.0);
+            let label_idx = self.ctx.intern_string(&label);
+
+            let skip_patch = self.emit_jump_placeholder();
+            let entry_point = self.code.len() as u32;
+            self.emit_expr(inner);
+            self.emit_op(Op::Return);
+            self.patch_jump_target(skip_patch);
+            self.emit_op(Op::MakeThunk);
+            self.emit_u32(entry_point);
+            self.emit_u32(label_idx);
+            let (_, local_idx) = self.resolve_thunk(id);
+            self.emit_op(Op::StoreLocal);
+            self.emit_u32(local_idx);
+        }
+    }
+
+    fn emit_expr(&mut self, ir: RawIrRef<'_>) {
+        match ir.deref() {
+            &Ir::Int(x) => {
+                let idx = self.ctx.intern_constant(Constant::Int(x));
+                self.emit_op(Op::PushConst);
+                self.emit_u32(idx);
+            }
+            &Ir::Float(x) => {
+                let idx = self.ctx.intern_constant(Constant::Float(x.to_bits()));
+                self.emit_op(Op::PushConst);
+                self.emit_u32(idx);
+            }
+            &Ir::Bool(true) => self.emit_op(Op::PushTrue),
+            &Ir::Bool(false) => self.emit_op(Op::PushFalse),
+            Ir::Null => self.emit_op(Op::PushNull),
+            Ir::Str(s) => {
+                let idx = self.ctx.intern_string(s.deref());
+                self.emit_op(Op::PushString);
+                self.emit_u32(idx);
+            }
+            &Ir::Path(p) => {
+                self.emit_expr(p);
+                self.emit_op(Op::ResolvePath);
+            }
+            &Ir::If { cond, consq, alter } => {
+                self.emit_expr(cond);
+                self.emit_op(Op::ForceBool);
+
+                self.emit_op(Op::JumpIfFalse);
+                let else_placeholder = self.emit_i32_placeholder();
+                let after_jif = self.code.len();
+
+                self.emit_expr(consq);
+
+                self.emit_op(Op::Jump);
+                let end_placeholder = self.emit_i32_placeholder();
+                let after_jump = self.code.len();
+
+                let else_offset = (after_jump as i32) - (after_jif as i32);
+                self.patch_i32(else_placeholder, else_offset);
+
+                self.emit_expr(alter);
+
+                let end_offset = (self.code.len() as i32) - (after_jump as i32);
+                self.patch_i32(end_placeholder, end_offset);
+            }
+            &Ir::BinOp { lhs, rhs, kind } => {
+                self.emit_binop(lhs, rhs, kind);
+            }
+            &Ir::UnOp { rhs, kind } => match kind {
+                UnOpKind::Neg => {
+                    self.emit_expr(rhs);
+                    self.emit_op(Op::OpNeg);
+                }
+                UnOpKind::Not => {
+                    self.emit_expr(rhs);
+                    self.emit_op(Op::OpNot);
+                }
+            },
+            &Ir::Func {
+                body,
+                ref param,
+                arg,
+                ref thunks,
+            } => {
+                self.emit_func(arg, thunks, param, body);
+            }
+            Ir::AttrSet { stcs, dyns } => {
+                self.emit_attrset(stcs, dyns);
+            }
+            Ir::List { items } => {
+                for &item in items.iter() {
+                    self.emit_expr(item);
+                }
+                self.emit_op(Op::MakeList);
+                self.emit_u32(items.len() as u32);
+            }
+            &Ir::Call { func, arg, span } => {
+                self.emit_expr(func);
+                self.emit_expr(arg);
+                let span_id = self.ctx.register_span(span);
+                self.emit_op(Op::Call);
+                self.emit_u32(span_id);
+            }
+            &Ir::Arg(id) => {
+                let (layer, local) = self.resolve_arg(id);
+                self.emit_load(layer, local);
+            }
+            &Ir::TopLevel { body, ref thunks } => {
+                self.emit_toplevel_inner(body, thunks);
+            }
+            &Ir::Select {
+                expr,
+                ref attrpath,
+                default,
+                span,
+            } => {
+                self.emit_select(expr, attrpath, default, span);
+            }
+            &Ir::Thunk(id) => {
+                let (layer, local) = self.resolve_thunk(id);
+                self.emit_load(layer, local);
+            }
+            Ir::Builtins => {
+                self.emit_op(Op::LoadBuiltins);
+            }
+            &Ir::Builtin(name) => {
+                let sym = self.ctx.get_sym(name).to_string();
+                let idx = self.ctx.intern_string(&sym);
+                self.emit_op(Op::LoadBuiltin);
+                self.emit_u32(idx);
+            }
+            &Ir::ConcatStrings {
+                ref parts,
+                force_string,
+            } => {
+                for &part in parts.iter() {
+                    self.emit_expr(part);
+                }
+                self.emit_op(Op::ConcatStrings);
+                self.emit_u16(parts.len() as u16);
+                self.emit_u8(if force_string { 1 } else { 0 });
+            }
+            &Ir::HasAttr { lhs, ref rhs } => {
+                self.emit_has_attr(lhs, rhs);
+            }
+            Ir::Assert {
+                assertion,
+                expr,
+                assertion_raw,
+                span,
+            } => {
+                let raw_idx = self.ctx.intern_string(assertion_raw);
+                let span_id = self.ctx.register_span(*span);
+                self.emit_expr(*assertion);
+                self.emit_expr(*expr);
+                self.emit_op(Op::Assert);
+                self.emit_u32(raw_idx);
+                self.emit_u32(span_id);
+            }
+            &Ir::CurPos(span) => {
+                let span_id = self.ctx.register_span(span);
+                self.emit_op(Op::MkPos);
+                self.emit_u32(span_id);
+            }
+            &Ir::ReplBinding(name) => {
+                let sym = self.ctx.get_sym(name).to_string();
+                let idx = self.ctx.intern_string(&sym);
+                self.emit_op(Op::LoadReplBinding);
+                self.emit_u32(idx);
+            }
+            &Ir::ScopedImportBinding(name) => {
+                let sym = self.ctx.get_sym(name).to_string();
+                let idx = self.ctx.intern_string(&sym);
+                self.emit_op(Op::LoadScopedBinding);
+                self.emit_u32(idx);
+            }
+            &Ir::With {
+                namespace,
+                body,
+                ref thunks,
+            } => {
+                self.emit_with(namespace, body, thunks);
+            }
+            &Ir::WithLookup(name) => {
+                let sym = self.ctx.get_sym(name).to_string();
+                let idx = self.ctx.intern_string(&sym);
+                self.emit_op(Op::WithLookup);
+                self.emit_u32(idx);
+            }
+        }
+    }
+
+    fn emit_binop(&mut self, lhs: RawIrRef<'_>, rhs: RawIrRef<'_>, kind: BinOpKind) {
+        use BinOpKind::*;
+        match kind {
+            And => {
+                self.emit_expr(lhs);
+                self.emit_op(Op::ForceBool);
+                self.emit_op(Op::JumpIfFalse);
+                let skip_placeholder = self.emit_i32_placeholder();
+                let after_jif = self.code.len();
+
+                self.emit_expr(rhs);
+                self.emit_op(Op::ForceBool);
+                self.emit_op(Op::Jump);
+                let end_placeholder = self.emit_i32_placeholder();
+                let after_jump = self.code.len();
+
+                let false_offset = (after_jump as i32) - (after_jif as i32);
+                self.patch_i32(skip_placeholder, false_offset);
+
+                self.emit_op(Op::PushFalse);
+
+                let end_offset = (self.code.len() as i32) - (after_jump as i32);
+                self.patch_i32(end_placeholder, end_offset);
+            }
+            Or => {
+                self.emit_expr(lhs);
+                self.emit_op(Op::ForceBool);
+                self.emit_op(Op::JumpIfTrue);
+                let skip_placeholder = self.emit_i32_placeholder();
+                let after_jit = self.code.len();
+
+                self.emit_expr(rhs);
+                self.emit_op(Op::ForceBool);
+                self.emit_op(Op::Jump);
+                let end_placeholder = self.emit_i32_placeholder();
+                let after_jump = self.code.len();
+
+                let true_offset = (after_jump as i32) - (after_jit as i32);
+                self.patch_i32(skip_placeholder, true_offset);
+
+                self.emit_op(Op::PushTrue);
+
+                let end_offset = (self.code.len() as i32) - (after_jump as i32);
+                self.patch_i32(end_placeholder, end_offset);
+            }
+            Impl => {
+                self.emit_expr(lhs);
+                self.emit_op(Op::ForceBool);
+                self.emit_op(Op::JumpIfFalse);
+                let skip_placeholder = self.emit_i32_placeholder();
+                let after_jif = self.code.len();
+
+                self.emit_expr(rhs);
+                self.emit_op(Op::ForceBool);
+                self.emit_op(Op::Jump);
+                let end_placeholder = self.emit_i32_placeholder();
+                let after_jump = self.code.len();
+
+                let true_offset = (after_jump as i32) - (after_jif as i32);
+                self.patch_i32(skip_placeholder, true_offset);
+
+                self.emit_op(Op::PushTrue);
+
+                let end_offset = (self.code.len() as i32) - (after_jump as i32);
+                self.patch_i32(end_placeholder, end_offset);
+            }
+            PipeL => {
+                self.emit_expr(rhs);
+                self.emit_expr(lhs);
+                self.emit_op(Op::CallNoSpan);
+            }
+            PipeR => {
+                self.emit_expr(lhs);
+                self.emit_expr(rhs);
+                self.emit_op(Op::CallNoSpan);
+            }
+            _ => {
+                self.emit_expr(lhs);
+                self.emit_expr(rhs);
+                self.emit_op(match kind {
+                    Add => Op::OpAdd,
+                    Sub => Op::OpSub,
+                    Mul => Op::OpMul,
+                    Div => Op::OpDiv,
+                    Eq => Op::OpEq,
+                    Neq => Op::OpNeq,
+                    Lt => Op::OpLt,
+                    Gt => Op::OpGt,
+                    Leq => Op::OpLeq,
+                    Geq => Op::OpGeq,
+                    Con => Op::OpConcat,
+                    Upd => Op::OpUpdate,
+                    _ => unreachable!(),
+                });
+            }
+        }
+    }
+
+    fn emit_func(
+        &mut self,
+        arg: ArgId,
+        thunks: &[(ThunkId, RawIrRef<'_>)],
+        param: &Option<Param<'_>>,
+        body: RawIrRef<'_>,
+    ) {
+        let with_thunk_count = self.count_with_thunks(body);
+        let total_slots = thunks.len() + with_thunk_count;
+
+        let all_thunks = self.collect_all_thunks(thunks, body);
+        let thunk_ids: Vec<ThunkId> = all_thunks.iter().map(|&(id, _)| id).collect();
+
+        let skip_patch = self.emit_jump_placeholder();
+        let entry_point = self.code.len() as u32;
+        self.push_scope(true, Some(arg), &thunk_ids);
+        self.emit_scope_thunks(thunks);
+        self.emit_expr(body);
+        self.emit_op(Op::Return);
+        self.pop_scope();
+        self.patch_jump_target(skip_patch);
+
+        if let Some(Param {
+            required,
+            optional,
+            ellipsis,
+        }) = param
+        {
+            self.emit_op(Op::MakePatternClosure);
+            self.emit_u32(entry_point);
+            self.emit_u32(total_slots as u32);
+            self.emit_u16(required.len() as u16);
+            self.emit_u16(optional.len() as u16);
+            self.emit_u8(if *ellipsis { 1 } else { 0 });
+
+            for &(sym, _) in required.iter() {
+                let name = self.ctx.get_sym(sym).to_string();
+                let idx = self.ctx.intern_string(&name);
+                self.emit_u32(idx);
+            }
+            for &(sym, _) in optional.iter() {
+                let name = self.ctx.get_sym(sym).to_string();
+                let idx = self.ctx.intern_string(&name);
+                self.emit_u32(idx);
+            }
+            for &(sym, span) in required.iter().chain(optional.iter()) {
+                let name = self.ctx.get_sym(sym).to_string();
+                let name_idx = self.ctx.intern_string(&name);
+                let span_id = self.ctx.register_span(span);
+                self.emit_u32(name_idx);
+                self.emit_u32(span_id);
+            }
+        } else {
+            self.emit_op(Op::MakeClosure);
+            self.emit_u32(entry_point);
+            self.emit_u32(total_slots as u32);
+        }
+    }
+
+    fn emit_attrset(
+        &mut self,
+        stcs: &crate::ir::HashMap<'_, SymId, (RawIrRef<'_>, TextRange)>,
+        dyns: &[(RawIrRef<'_>, RawIrRef<'_>, TextRange)],
+    ) {
+        if stcs.is_empty() && dyns.is_empty() {
+            self.emit_op(Op::MakeEmptyAttrs);
+            return;
+        }
+
+        if !dyns.is_empty() {
+            for (&sym, &(val, _)) in stcs.iter() {
+                let key = self.ctx.get_sym(sym).to_string();
+                let idx = self.ctx.intern_string(&key);
+                self.emit_op(Op::PushString);
+                self.emit_u32(idx);
+                self.emit_expr(val);
+            }
+            for (_, &(_, span)) in stcs.iter() {
+                let span_id = self.ctx.register_span(span);
+                let idx = self.ctx.intern_constant(Constant::Int(span_id as i64));
+                self.emit_op(Op::PushConst);
+                self.emit_u32(idx);
+            }
+            for &(key, val, span) in dyns.iter() {
+                self.emit_expr(key);
+                self.emit_expr(val);
+                let span_id = self.ctx.register_span(span);
+                let idx = self.ctx.intern_constant(Constant::Int(span_id as i64));
+                self.emit_op(Op::PushConst);
+                self.emit_u32(idx);
+            }
+            self.emit_op(Op::MakeAttrsDyn);
+            self.emit_u32(stcs.len() as u32);
+            self.emit_u32(dyns.len() as u32);
+        } else {
+            for (&sym, &(val, _)) in stcs.iter() {
+                let key = self.ctx.get_sym(sym).to_string();
+                let idx = self.ctx.intern_string(&key);
+                self.emit_op(Op::PushString);
+                self.emit_u32(idx);
+                self.emit_expr(val);
+            }
+            for (_, &(_, span)) in stcs.iter() {
+                let span_id = self.ctx.register_span(span);
+                let idx = self.ctx.intern_constant(Constant::Int(span_id as i64));
+                self.emit_op(Op::PushConst);
+                self.emit_u32(idx);
+            }
+            self.emit_op(Op::MakeAttrs);
+            self.emit_u32(stcs.len() as u32);
+        }
+    }
+
+    fn emit_select(
+        &mut self,
+        expr: RawIrRef<'_>,
+        attrpath: &[Attr<RawIrRef<'_>>],
+        default: Option<RawIrRef<'_>>,
+        span: TextRange,
+    ) {
+        self.emit_expr(expr);
+        for attr in attrpath.iter() {
+            match attr {
+                Attr::Str(sym, _) => {
+                    let key = self.ctx.get_sym(*sym).to_string();
+                    let idx = self.ctx.intern_string(&key);
+                    self.emit_op(Op::PushString);
+                    self.emit_u32(idx);
+                }
+                Attr::Dynamic(expr, _) => {
+                    self.emit_expr(*expr);
+                }
+            }
+        }
+
+        if let Some(default) = default {
+            self.emit_expr(default);
+            let span_id = self.ctx.register_span(span);
+            self.emit_op(Op::SelectDefault);
+            self.emit_u16(attrpath.len() as u16);
+            self.emit_u32(span_id);
+        } else {
+            let span_id = self.ctx.register_span(span);
+            self.emit_op(Op::Select);
+            self.emit_u16(attrpath.len() as u16);
+            self.emit_u32(span_id);
+        }
+    }
+
+    fn emit_has_attr(&mut self, lhs: RawIrRef<'_>, rhs: &[Attr<RawIrRef<'_>>]) {
+        self.emit_expr(lhs);
+        for attr in rhs.iter() {
+            match attr {
+                Attr::Str(sym, _) => {
+                    let key = self.ctx.get_sym(*sym).to_string();
+                    let idx = self.ctx.intern_string(&key);
+                    self.emit_op(Op::PushString);
+                    self.emit_u32(idx);
+                }
+                Attr::Dynamic(expr, _) => {
+                    self.emit_expr(*expr);
+                }
+            }
+        }
+        self.emit_op(Op::HasAttr);
+        self.emit_u16(rhs.len() as u16);
+    }
+
+    fn emit_with(
+        &mut self,
+        namespace: RawIrRef<'_>,
+        body: RawIrRef<'_>,
+        thunks: &[(ThunkId, RawIrRef<'_>)],
+    ) {
+        self.emit_expr(namespace);
+        self.emit_op(Op::PushWith);
+        self.emit_scope_thunks(thunks);
+        self.emit_expr(body);
+        self.emit_op(Op::PopWith);
+    }
+
+    fn emit_toplevel_inner(&mut self, body: RawIrRef<'_>, thunks: &[(ThunkId, RawIrRef<'_>)]) {
+        self.emit_scope_thunks(thunks);
+        self.emit_expr(body);
+    }
+}

nix-js/src/codegen.rs

@@ -1,9 +1,51 @@
 use std::fmt::{self, Write as _};
+use std::ops::Deref;
 use std::path::Path;
 
-use crate::ir::*;
+use rnix::TextRange;
 
-pub(crate) struct CodeBuffer {
+use crate::ir::*;
+use crate::value::Symbol;
+
+macro_rules! code {
+    ($buf:expr, $ctx:expr; $($item:expr)*) => {{
+        $(
+            ($item).compile($ctx, $buf);
+        )*
+    }};
+
+    ($buf:expr, $ctx:expr; $($item:expr)*) => {{
+        $(
+            ($item).compile($ctx, $buf);
+        )*
+    }};
+
+    ($buf:expr, $fmt:literal, $($arg:tt)*) => {
+        write!($buf, $fmt, $($arg)*).unwrap()
+    };
+
+    ($buf:expr, $fmt:literal) => {
+        write!($buf, $fmt).unwrap()
+    };
+}
+
+pub(crate) fn compile<const SCOPED: bool>(expr: RawIrRef<'_>, ctx: &impl CodegenContext) -> String {
+    let mut buf = CodeBuffer::with_capacity(8192);
+
+    code!(
+        &mut buf, ctx;
+        "((" { if SCOPED { "_s" } else { "" } } ")=>{"
+            "const _d="
+                quoted(&ctx.get_current_dir().display().to_string())
+            ",_w=null;"
+            "return " expr
+        "})" { if SCOPED { "" } else { "()" } }
+    );
+
+    buf.into_string()
+}
+
+struct CodeBuffer {
     buf: String,
 }
 
@@ -82,49 +124,6 @@ fn joined<Ctx: CodegenContext, I: Iterator, F: Fn(&Ctx, &mut CodeBuffer, I::Item
     }
 }
 
-macro_rules! code {
-    ($buf:expr, $ctx:expr; $($item:expr),* $(,)?) => {{
-        $(
-            ($item).compile($ctx, $buf);
-        )*
-    }};
-
-    ($buf:expr, $ctx:expr; $($item:expr)*) => {{
-        $(
-            ($item).compile($ctx, $buf);
-        )*
-    }};
-
-    ($buf:expr, $fmt:literal, $($arg:tt)*) => {
-        write!($buf, $fmt, $($arg)*).unwrap()
-    };
-
-    ($buf:expr, $lit:literal) => {
-        $buf.push_str($lit)
-    };
-}
-
-pub(crate) fn compile(expr: &Ir, ctx: &impl CodegenContext) -> String {
-    let mut buf = CodeBuffer::with_capacity(8192);
-
-    code!(&mut buf, ctx; "(()=>{");
-
-    if std::env::var("NIX_JS_DEBUG_THUNKS").is_ok() {
-        code!(&mut buf, ctx; "Nix.DEBUG_THUNKS.enabled=true;");
-    }
-
-    code!(&mut buf, ctx;
-        "Nix.builtins.storeDir="
-        quoted(ctx.get_store_dir())
-        ";const currentDir="
-        quoted(&ctx.get_current_dir().display().to_string())
-        ";return "
-        expr
-        "})()");
-
-    buf.into_string()
-}
-
 trait Compile<Ctx: CodegenContext> {
     fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer);
 }
@@ -141,6 +140,12 @@ impl<Ctx: CodegenContext> Compile<Ctx> for usize {
     }
 }
 
+impl<Ctx: CodegenContext> Compile<Ctx> for bool {
+    fn compile(&self, _ctx: &Ctx, buf: &mut CodeBuffer) {
+        let _ = write!(buf, "{self}");
+    }
+}
+
 impl<Ctx: CodegenContext> Compile<Ctx> for Quoted<'_> {
     fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
         code!(buf, ctx; "\"" escaped(self.0) "\"")
@@ -166,474 +171,448 @@ where
 
 impl<Ctx: CodegenContext> Compile<Ctx> for rnix::TextRange {
     fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
-        code!(
-            buf,
-            "\"{}:{}:{}\"",
-            ctx.get_current_source_id(),
-            usize::from(self.start()),
-            usize::from(self.end())
-        );
+        code!(buf, "{}", ctx.register_span(*self));
     }
 }
 
 pub(crate) trait CodegenContext {
-    fn get_ir(&self, id: ExprId) -> &Ir;
-    fn get_sym(&self, id: SymId) -> &str;
+    fn get_sym(&self, id: SymId) -> Symbol<'_>;
     fn get_current_dir(&self) -> &Path;
     fn get_store_dir(&self) -> &str;
     fn get_current_source_id(&self) -> usize;
-    fn get_current_source(&self) -> crate::error::Source;
+    fn register_span(&self, range: rnix::TextRange) -> usize;
 }
 
-impl<Ctx: CodegenContext> Compile<Ctx> for ExprId {
+impl<Ctx: CodegenContext> Compile<Ctx> for Symbol<'_> {
     fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
-        ctx.get_ir(*self).compile(ctx, buf);
+        quoted(self).compile(ctx, buf);
     }
 }
 
-impl<Ctx: CodegenContext> Compile<Ctx> for Ir {
+impl<Ctx: CodegenContext> Compile<Ctx> for RawIrRef<'_> {
     fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
-        match self {
+        match self.deref() {
             Ir::Int(int) => {
-                code!(buf, "{}n", int.inner);
+                code!(buf, "{}n", int);
             }
             Ir::Float(float) => {
-                code!(buf, "{}", float.inner);
+                code!(buf, "{}", float);
             }
             Ir::Bool(bool) => {
-                code!(buf, "{}", bool.inner);
+                code!(buf, "{}", bool);
             }
-            Ir::Null(_) => {
+            Ir::Null => {
                 code!(buf, ctx; "null");
             }
             Ir::Str(s) => {
-                code!(buf, ctx; quoted(&s.val));
+                code!(buf, ctx; quoted(s));
             }
             Ir::Path(p) => {
-                code!(buf, ctx; "Nix.resolvePath(currentDir," ctx.get_ir(p.expr) ")");
+                // Nix.resolvePath
+                code!(buf, ctx; "$r(_d," p ")");
             }
-            Ir::If(x) => x.compile(ctx, buf),
-            Ir::BinOp(x) => x.compile(ctx, buf),
-            Ir::UnOp(x) => x.compile(ctx, buf),
-            Ir::Func(x) => x.compile(ctx, buf),
-            Ir::AttrSet(x) => x.compile(ctx, buf),
-            Ir::List(x) => x.compile(ctx, buf),
-            Ir::Call(x) => x.compile(ctx, buf),
-            Ir::Arg(x) => {
-                code!(buf, "arg{}", x.inner.0);
+            Ir::If { cond, consq, alter } => {
+                code!(buf, ctx; "$fb(" cond ")?(" consq "):(" alter ")");
             }
-            Ir::TopLevel(x) => x.compile(ctx, buf),
-            Ir::Select(x) => x.compile(ctx, buf),
-            &Ir::Thunk(Thunk { inner: expr_id, .. }) => {
-                code!(buf, "expr{}", expr_id.0);
-            }
-            Ir::Builtins(_) => {
-                code!(buf, ctx; "Nix.builtins");
-            }
-            &Ir::Builtin(Builtin { inner: name, .. }) => {
+            &Ir::BinOp { lhs, rhs, kind } => compile_binop(lhs, rhs, kind, ctx, buf),
+            &Ir::UnOp { rhs, kind } => compile_unop(rhs, kind, ctx, buf),
+            &Ir::Func {
+                body,
+                ref param,
+                arg,
+                ref thunks,
+            } => compile_func(arg, thunks, param, body, ctx, buf),
+            Ir::AttrSet { stcs, dyns } => compile_attrset(stcs, dyns, ctx, buf),
+            Ir::List { items } => compile_list(items, ctx, buf),
+            Ir::Call { func, arg, span } => {
                 code!(buf, ctx;
-                    "Nix.builtins[",
-                    quoted(ctx.get_sym(name)),
-                    "]"
+                    "$c("
+                        func
+                        ","
+                        arg
+                        ","
+                        span
+                    ")"
                 );
             }
-            Ir::ConcatStrings(x) => x.compile(ctx, buf),
-            Ir::HasAttr(x) => x.compile(ctx, buf),
-            &Ir::Assert(Assert {
+            Ir::Arg(x) => {
+                code!(buf, "a{}", x.0);
+            }
+            &Ir::TopLevel { body, ref thunks } => compile_toplevel(body, thunks, ctx, buf),
+            &Ir::Select {
+                expr,
+                ref attrpath,
+                default,
+                span,
+            } => compile_select(expr, attrpath, default, span, ctx, buf),
+            Ir::Thunk(ThunkId(id)) => {
+                code!(buf, "e{}", id);
+            }
+            Ir::Builtins => {
+                // Nix.builtins
+                code!(buf, ctx; "$b");
+            }
+            &Ir::Builtin(name) => {
+                // Nix.builtins
+                code!(buf, ctx; "$b.get(" ctx.get_sym(name) ")");
+            }
+            &Ir::ConcatStrings {
+                ref parts,
+                force_string,
+            } => compile_concat_strings(parts, force_string, ctx, buf),
+            &Ir::HasAttr { lhs, ref rhs } => compile_has_attr(lhs, rhs, ctx, buf),
+            Ir::Assert {
                 assertion,
                 expr,
-                ref assertion_raw,
+                assertion_raw,
                 span: assert_span,
-            }) => {
-                let assertion_ir = ctx.get_ir(assertion);
-                let assertion_span = assertion_ir.span();
-
+            } => {
+                // Nix.assert
                 code!(buf, ctx;
-                    "Nix.assert(Nix.withContext(\"while evaluating the condition of the assert statement\",",
-                    assertion_span,
-                    ",()=>(",
-                    assertion_ir,
-                    ")),",
-                    ctx.get_ir(expr),
-                    ",",
-                    quoted(assertion_raw),
-                    ",",
-                    assert_span,
+                    "$a("
+                        assertion
+                        ","
+                        expr
+                        ","
+                        quoted(assertion_raw)
+                        ","
+                        assert_span
                     ")"
                 );
             }
-            Ir::CurPos(cur_pos) => {
-                code!(buf, ctx;
-                    "Nix.mkPos(",
-                    cur_pos.span,
-                    ")"
-                );
+            Ir::CurPos(span) => {
+                // Nix.mkPos
+                code!(buf, ctx; "$mp(" span ")");
+            }
+            &Ir::ReplBinding(name) => {
+                // Nix.getReplBinding
+                code!(buf, ctx; "$gb(" ctx.get_sym(name) ")");
+            }
+            &Ir::ScopedImportBinding(name) => {
+                code!(buf, ctx; "_s.get(" ctx.get_sym(name) ")");
+            }
+            &Ir::With {
+                namespace,
+                body,
+                ref thunks,
+            } => compile_with(namespace, body, thunks, ctx, buf),
+            &Ir::WithLookup(name) => {
+                // Nix.lookupWith
+                code!(buf, ctx; "$l(" ctx.get_sym(name) ",_w)");
             }
         }
     }
 }
 
-impl<Ctx: CodegenContext> Compile<Ctx> for If {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
-        let &If {
-            cond,
-            consq,
-            alter,
-            span: _,
-        } = self;
-        let cond_ir = ctx.get_ir(cond);
-        let cond_span = cond_ir.span();
-
-        code!(buf, ctx;
-            "(Nix.withContext(\"while evaluating a branch condition\"," cond_span ",()=>Nix.forceBool(" cond_ir ")))"
-            "?(" consq "):(" alter ")"
-        );
-    }
-}
-
-impl<Ctx: CodegenContext> Compile<Ctx> for BinOp {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
+fn compile_binop<'ir>(
+    lhs: RawIrRef<'ir>,
+    rhs: RawIrRef<'ir>,
+    kind: BinOpKind,
+    ctx: &impl CodegenContext,
+    buf: &mut CodeBuffer,
+) {
     use BinOpKind::*;
-
-        let lhs = ctx.get_ir(self.lhs);
-        let rhs = ctx.get_ir(self.rhs);
-
-        match self.kind {
+    match kind {
         Add | Sub | Mul | Div | Eq | Neq | Lt | Gt | Leq | Geq | Con | Upd => {
-                let op_name = match self.kind {
-                    Add => "+",
-                    Sub => "-",
-                    Mul => "*",
-                    Div => "/",
-                    Eq => "==",
-                    Neq => "!=",
-                    Lt => "<",
-                    Gt => ">",
-                    Leq => "<=",
-                    Geq => ">=",
-                    Con => "++",
-                    Upd => "//",
-                    _ => unreachable!(),
-                };
-                let op_func = match self.kind {
-                    Add => "Nix.op.add",
-                    Sub => "Nix.op.sub",
-                    Mul => "Nix.op.mul",
-                    Div => "Nix.op.div",
-                    Eq => "Nix.op.eq",
-                    Neq => "Nix.op.neq",
-                    Lt => "Nix.op.lt",
-                    Gt => "Nix.op.gt",
-                    Leq => "Nix.op.lte",
-                    Geq => "Nix.op.gte",
-                    Con => "Nix.op.concat",
-                    Upd => "Nix.op.update",
+            let op_func = match kind {
+                Add => "$oa",
+                Sub => "$os",
+                Mul => "$om",
+                Div => "$od",
+                Eq => "$oe",
+                Neq => "!$oe",
+                Lt => "$ol",
+                Gt => "$og",
+                Leq => "!$og",
+                Geq => "!$ol",
+                Con => "$oc",
+                Upd => "$ou",
                 _ => unreachable!(),
             };
 
             code!(
                 buf, ctx;
-                    "Nix.withContext(\"while evaluating the " op_name " operator\"," self.span ",()=>(" op_func "(" lhs "," rhs ")))"
+                op_func "(" lhs "," rhs ")"
             );
         }
         And => {
             code!(
                 buf, ctx;
-                    "Nix.withContext(\"while evaluating the && operator\"," self.span ",()=>(Nix.forceBool(" lhs ")&&Nix.forceBool(" rhs ")))"
+                "$fb(" lhs ")" "&&" "$fb(" rhs ")"
             );
         }
         Or => {
             code!(
                 buf, ctx;
-                    "Nix.withContext(\"while evaluating the || operator\"," self.span ",()=>(Nix.forceBool(" lhs ")||Nix.forceBool(" rhs ")))"
+                "$fb(" lhs ")" "||" "$fb(" rhs ")"
             );
         }
         Impl => {
             code!(
                 buf, ctx;
-                    "Nix.withContext(\"while evaluating the -> operator\"," self.span ",()=>(!Nix.forceBool(" lhs ")||Nix.forceBool(" rhs ")))"
+                "!$fb(" lhs ")" "||" "$fb(" rhs ")"
             );
         }
         PipeL => {
-                code!(buf, ctx;
-                    "Nix.call(",
-                    rhs,
-                    ",",
-                    lhs,
-                    ")"
-                );
+            code!(buf, ctx; "$c(" rhs "," lhs ")");
         }
         PipeR => {
-                code!(buf, ctx;
-                    "Nix.call(",
-                    lhs,
-                    ",",
-                    rhs,
-                    ")"
-                );
-            }
+            code!(buf, ctx; "$c(" lhs "," rhs ")");
         }
     }
 }
 
-impl<Ctx: CodegenContext> Compile<Ctx> for UnOp {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
+fn compile_unop(
+    rhs: RawIrRef<'_>,
+    kind: UnOpKind,
+    ctx: &impl CodegenContext,
+    buf: &mut CodeBuffer,
+) {
     use UnOpKind::*;
-        match self.kind {
+    match kind {
         Neg => {
-                code!(buf, ctx;
-                    "Nix.op.sub(0n,",
-                    ctx.get_ir(self.rhs),
-                    ")"
-                );
+            // 0 - rhs
+            code!(buf, ctx; "$os(0n," rhs ")");
         }
         Not => {
-                code!(buf, ctx;
-                    "Nix.op.bnot(",
-                    ctx.get_ir(self.rhs),
-                    ")"
-                );
-            }
+            code!(buf, ctx; "!$fb(" rhs ")");
         }
     }
 }
 
-impl<Ctx: CodegenContext> Compile<Ctx> for Func {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
-        let id = ctx.get_ir(self.arg).as_ref().unwrap_arg().inner.0;
-
-        let has_thunks = !self.thunks.is_empty();
+fn compile_func<'ir, Ctx: CodegenContext>(
+    ArgId(id): ArgId,
+    thunks: &[(ThunkId, RawIrRef<'ir>)],
+    param: &Option<Param<'ir>>,
+    body: RawIrRef<'ir>,
+    ctx: &Ctx,
+    buf: &mut CodeBuffer,
+) {
+    let has_thunks = !thunks.is_empty();
 
     if let Some(Param {
         required,
         optional,
         ellipsis,
-        }) = &self.param
+    }) = &param
     {
-            code!(buf, "Nix.mkFunction(arg{}=>", id);
+        code!(buf, "$mf(a{}=>", id);
         if has_thunks {
-                code!(buf, ctx; "{", &self.thunks, "return ", self.body, "}");
+            code!(buf, ctx; "{" thunks "return " body "}");
         } else {
-                code!(buf, ctx; "(", self.body, ")");
+            code!(buf, ctx; "(" body ")");
         }
         code!(buf, ctx;
             ",["
-                joined(required.iter(), ",", |ctx: &Ctx, buf, &sym| {
-                    code!(buf, ctx; quoted(ctx.get_sym(sym)));
+            joined(required.iter(), ",", |ctx: &Ctx, buf, &(sym, _)| {
+                code!(buf, ctx; ctx.get_sym(sym));
             })
             "],["
-                joined(optional.iter(), ",", |ctx: &Ctx, buf, &sym| {
-                    code!(buf, ctx; quoted(ctx.get_sym(sym)));
+            joined(optional.iter(), ",", |ctx: &Ctx, buf, &(sym, _)| {
+                code!(buf, ctx; ctx.get_sym(sym));
             })
-                "],"
-            );
-            code!(buf, "{})", ellipsis);
-        } else {
-            code!(buf, "arg{}=>", id);
-            if has_thunks {
-                code!(buf, ctx; "{", &self.thunks, "return ", self.body, "}");
-            } else {
-                code!(buf, ctx; "(", self.body, ")");
-            }
-        }
-    }
-}
-
-impl<Ctx: CodegenContext> Compile<Ctx> for Call {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
-        code!(buf, ctx;
-            "Nix.call(",
-            ctx.get_ir(self.func),
-            ",",
-            ctx.get_ir(self.arg),
-            ",",
-            self.span,
+            "],new Map(["
+            joined(required.iter().chain(optional.iter()), ",", |ctx: &Ctx, buf, &(sym, span)| {
+                code!(buf, ctx; "[" ctx.get_sym(sym) "," span "]");
+            })
+            "]),"
+            ellipsis
             ")"
         );
+    } else {
+        code!(buf, "a{}=>", id);
+        if has_thunks {
+            code!(buf, ctx; "{" thunks "return " body "}");
+        } else {
+            code!(buf, ctx; "(" body ")");
+        }
     }
 }
 
-impl<Ctx: CodegenContext> Compile<Ctx> for [(ExprId, ExprId)] {
+impl<'ir, Ctx: CodegenContext> Compile<Ctx> for [(ThunkId, RawIrRef<'ir>)] {
     fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
         if self.is_empty() {
             return;
         }
 
-        for &(slot, inner) in self {
-            let inner_ir = ctx.get_ir(inner);
-            let inner_span = inner_ir.span();
-
-            code!(buf, "let expr{}=Nix.createThunk(()=>(", slot.0);
-            inner_ir.compile(ctx, buf);
-            code!(
-                buf,
-                "),\"expr{} {}:{}:{}\");",
-                slot.0,
-                ctx.get_current_source().get_name(),
-                usize::from(inner_span.start()),
-                usize::from(inner_span.end())
-            );
-        }
-    }
-}
-
-impl<Ctx: CodegenContext> Compile<Ctx> for TopLevel {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
-        if self.thunks.is_empty() {
-            ctx.get_ir(self.body).compile(ctx, buf);
-        } else {
-            code!(buf, "(()=>{");
-            code!(buf, ctx; &self.thunks);
-            code!(buf, "return ");
-            ctx.get_ir(self.body).compile(ctx, buf);
-            code!(buf, "})()");
-        }
-    }
-}
-
-impl<Ctx: CodegenContext> Compile<Ctx> for Select {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
-        if let Some(default) = self.default {
-            code!(buf, ctx;
-                "Nix.selectWithDefault("
-                ctx.get_ir(self.expr)
-                ",["
-                joined(self.attrpath.iter(), ",", |ctx: &Ctx, buf, attr| {
-                    match attr {
-                        Attr::Str(sym, _) => code!(buf, ctx; quoted(ctx.get_sym(*sym))),
-                        Attr::Dynamic(expr_id, _) => code!(buf, ctx; ctx.get_ir(*expr_id)),
-                    }
-                })
-                "],"
-                ctx.get_ir(default)
-                ","
-                self.span
-                ")"
-            );
-        } else {
-            code!(buf, ctx;
-                "Nix.select("
-                ctx.get_ir(self.expr)
-                ",["
-                joined(self.attrpath.iter(), ",", |ctx: &Ctx, buf, attr| {
-                    match attr {
-                        Attr::Str(sym, _) => code!(buf, ctx; quoted(ctx.get_sym(*sym))),
-                        Attr::Dynamic(expr_id, _) => code!(buf, ctx; ctx.get_ir(*expr_id)),
-                    }
-                })
-                "],"
-                self.span
-                ")"
-            );
-        }
-    }
-}
-
-impl<Ctx: CodegenContext> Compile<Ctx> for AttrSet {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
-        if !self.dyns.is_empty() {
-            code!(buf, ctx;
-                "Nix.mkAttrsWithPos({"
-                joined(self.stcs.iter(), ",", |ctx: &Ctx, buf, (&sym, &(expr, _))| {
-                    let key = ctx.get_sym(sym);
-                    let val = ctx.get_ir(expr);
-
         code!(
             buf, ctx;
-                        quoted(key) ":Nix.withContext(\"while evaluating the attribute '" escaped(key) "'\"," val.span() ",()=>(" val "))"
+            "const "
+            joined(self.iter(), ",", |ctx: &Ctx, buf, &(slot, inner)| {
+                code!(buf, ctx; "e" slot.0 "=$t(()=>(" inner ")," "'e" slot.0 "')");
+            })
+            ";"
+        );
+    }
+}
+
+fn compile_toplevel<'ir, Ctx: CodegenContext>(
+    body: RawIrRef<'ir>,
+    thunks: &[(ThunkId, RawIrRef<'ir>)],
+    ctx: &Ctx,
+    buf: &mut CodeBuffer,
+) {
+    if thunks.is_empty() {
+        body.compile(ctx, buf);
+    } else {
+        code!(buf, ctx; "(()=>{" thunks "return " body "})()");
+    }
+}
+
+fn compile_with<'ir>(
+    namespace: RawIrRef<'ir>,
+    body: RawIrRef<'ir>,
+    thunks: &[(ThunkId, RawIrRef<'ir>)],
+    ctx: &impl CodegenContext,
+    buf: &mut CodeBuffer,
+) {
+    let has_thunks = !thunks.is_empty();
+    if has_thunks {
+        code!(buf, ctx; "((_w)=>{" thunks "return " body "})({env:" namespace ",last:_w})");
+    } else {
+        code!(buf, ctx; "((_w)=>(" body "))({env:" namespace ",last:_w})");
+    }
+}
+
+fn compile_select<'ir, Ctx: CodegenContext>(
+    expr: RawIrRef<'ir>,
+    attrpath: &[Attr<RawIrRef<'ir>>],
+    default: Option<RawIrRef<'ir>>,
+    span: TextRange,
+    ctx: &Ctx,
+    buf: &mut CodeBuffer,
+) {
+    if let Some(default) = default {
+        code!(buf, ctx;
+            "$sd("
+            expr
+            ",["
+            joined(attrpath.iter(), ",", |ctx: &Ctx, buf, attr| {
+                match attr {
+                    Attr::Str(sym, _) => code!(buf, ctx; ctx.get_sym(*sym)),
+                    Attr::Dynamic(expr_id, _) => code!(buf, ctx; *expr_id),
+                }
+            })
+            "],"
+            default
+            ","
+            span
+            ")"
+        );
+    } else {
+        code!(buf, ctx;
+            "$s("
+            expr
+            ",["
+            joined(attrpath.iter(), ",", |ctx: &Ctx, buf, attr| {
+                match attr {
+                    Attr::Str(sym, _) => code!(buf, ctx; ctx.get_sym(*sym)),
+                    Attr::Dynamic(expr, _) => code!(buf, ctx; expr),
+                }
+            })
+            "],"
+            span
+            ")"
+        );
+    }
+}
+
+fn compile_attrset<'ir, Ctx: CodegenContext>(
+    stcs: &HashMap<'ir, SymId, (RawIrRef<'ir>, TextRange)>,
+    dyns: &[(RawIrRef<'ir>, RawIrRef<'ir>, TextRange)],
+    ctx: &Ctx,
+    buf: &mut CodeBuffer,
+) {
+    if !dyns.is_empty() {
+        code!(buf, ctx;
+            "$ma(new Map(["
+            joined(stcs.iter(), ",", |ctx: &Ctx, buf, (&sym, &(val, _))| {
+                let key = ctx.get_sym(sym);
+                code!(
+                    buf, ctx;
+                    "[" key "," val "]"
                 );
             })
-                "},{"
-                joined(self.stcs.iter(), ",", |ctx: &Ctx, buf, (&sym, &(_, span))| {
-                    code!(buf, ctx; quoted(ctx.get_sym(sym)) ":" span);
+            "]),new Map(["
+            joined(stcs.iter(), ",", |ctx: &Ctx, buf, (&sym, &(_, span))| {
+                code!(buf, ctx; "[" ctx.get_sym(sym) "," span "]");
             })
-                "},{dynKeys:["
-                joined(self.dyns.iter(), ",", |ctx: &Ctx, buf, (key, _, _)| {
-                    code!(buf, ctx; ctx.get_ir(*key));
+            "]),{dynKeys:["
+            joined(dyns.iter(), ",", |ctx: &Ctx, buf, (key, _, _)| {
+                code!(buf, ctx; key);
             })
             "],dynVals:["
-                joined(self.dyns.iter(), ",", |ctx: &Ctx, buf, (_, val, _)| {
-                    let val = ctx.get_ir(*val);
-                    code!(
-                        buf, ctx;
-                        "Nix.withContext(\"while evaluating a dynamic attribute\"," val.span() ",()=>(" val "))"
-                    );
+            joined(dyns.iter(), ",", |ctx: &Ctx, buf, (_, val, _)| {
+                code!(buf, ctx; val);
             })
             "],dynSpans:["
-                joined(self.dyns.iter(), ",", |ctx: &Ctx, buf, (_, _, attr_span)| {
+            joined(dyns.iter(), ",", |ctx: &Ctx, buf, (_, _, attr_span)| {
                 code!(buf, ctx; attr_span);
             })
             "]})"
         );
-        } else if !self.stcs.is_empty() {
+    } else if !stcs.is_empty() {
         code!(buf, ctx;
-                "Nix.mkAttrsWithPos({"
-                joined(self.stcs.iter(), ",", |ctx: &Ctx, buf, (&sym, &(expr, _))| {
+            "$ma(new Map(["
+            joined(stcs.iter(), ",", |ctx: &Ctx, buf, (&sym, &(val, _))| {
                 let key = ctx.get_sym(sym);
-                    let val = ctx.get_ir(expr);
-
                 code!(
                     buf, ctx;
-                        quoted(key) ":Nix.withContext(\"while evaluating the attribute '" escaped(key) "'\"," val.span() ",()=>(" val "))"
+                    "[" key "," val "]"
                 );
             })
-                "},{"
-                joined(self.stcs.iter(), ",", |ctx: &Ctx, buf, (&sym, &(_, span))| {
-                    code!(buf, ctx; quoted(ctx.get_sym(sym)) ":" span);
+            "]),new Map(["
+            joined(stcs.iter(), ",", |ctx: &Ctx, buf, (&sym, &(_, span))| {
+                code!(buf, ctx; "[" ctx.get_sym(sym) "," span "]");
             })
-                "})"
+            "]))"
         );
     } else {
-            code!(buf, ctx; "{}");
-        }
+        code!(buf, ctx; "$e");
     }
 }
 
-impl<Ctx: CodegenContext> Compile<Ctx> for List {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
+fn compile_list<Ctx: CodegenContext>(items: &[RawIrRef<'_>], ctx: &Ctx, buf: &mut CodeBuffer) {
     code!(buf, ctx;
         "["
-            joined(self.items.iter().enumerate(), ",", |ctx: &Ctx, buf, (idx, item)| {
-                let item = ctx.get_ir(*item);
-                code!(
-                    buf, ctx;
-                    "Nix.withContext(\"while evaluating list element " idx "\"," item.span() ",()=>(" item "))"
-                );
+            joined(items.iter(), ",", |ctx: &Ctx, buf, item| {
+                code!(buf, ctx; item);
             })
         "]"
     );
 }
-}
 
-impl<Ctx: CodegenContext> Compile<Ctx> for ConcatStrings {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
+fn compile_concat_strings<Ctx: CodegenContext>(
+    parts: &[RawIrRef<'_>],
+    force_string: bool,
+    ctx: &Ctx,
+    buf: &mut CodeBuffer,
+) {
     code!(buf, ctx;
-            "Nix.concatStringsWithContext(["
-            joined(self.parts.iter(), ",", |ctx: &Ctx, buf, part| {
-                let part = ctx.get_ir(*part);
-                code!(
-                    buf, ctx;
-                    "Nix.withContext(\"while evaluating a path segment\"," part.span() ",()=>(" part "))"
-                );
+        "$cs(["
+        joined(parts.iter(), ",", |ctx: &Ctx, buf, part| {
+            code!(buf, ctx; part);
         })
-            "])"
+        "]," force_string ")"
     );
 }
-}
 
-impl<Ctx: CodegenContext> Compile<Ctx> for HasAttr {
-    fn compile(&self, ctx: &Ctx, buf: &mut CodeBuffer) {
+fn compile_has_attr<'ir, Ctx: CodegenContext>(
+    lhs: RawIrRef<'ir>,
+    rhs: &[Attr<RawIrRef<'ir>>],
+    ctx: &Ctx,
+    buf: &mut CodeBuffer,
+) {
     code!(buf, ctx;
-            "Nix.hasAttr("
-            ctx.get_ir(self.lhs)
+        "$h("
+        lhs
         ",["
-            joined(self.rhs.iter(), ",", |ctx: &Ctx, buf, attr| {
+        joined(rhs.iter(), ",", |ctx: &Ctx, buf, attr| {
             match attr {
-                    Attr::Str(sym, _) => code!(buf, ctx; quoted(ctx.get_sym(*sym))),
-                    Attr::Dynamic(expr_id, _) => code!(buf, ctx; ctx.get_ir(*expr_id)),
+                Attr::Str(sym, _) => code!(buf, ctx; ctx.get_sym(*sym)),
+                Attr::Dynamic(expr, _) => code!(buf, ctx; expr),
             }
         })
         "])"
     );
 }
-}

nix-js/src/derivation.rs

@@ -0,0 +1,142 @@
+use std::collections::{BTreeMap, BTreeSet};
+
+pub struct OutputInfo {
+    pub path: String,
+    pub hash_algo: String,
+    pub hash: String,
+}
+
+pub struct DerivationData {
+    pub name: String,
+    pub outputs: BTreeMap<String, OutputInfo>,
+    pub input_drvs: BTreeMap<String, BTreeSet<String>>,
+    pub input_srcs: BTreeSet<String>,
+    pub platform: String,
+    pub builder: String,
+    pub args: Vec<String>,
+    pub env: BTreeMap<String, String>,
+}
+
+fn escape_string(s: &str) -> String {
+    let mut result = String::with_capacity(s.len() + 2);
+    result.push('"');
+    for c in s.chars() {
+        match c {
+            '"' => result.push_str("\\\""),
+            '\\' => result.push_str("\\\\"),
+            '\n' => result.push_str("\\n"),
+            '\r' => result.push_str("\\r"),
+            '\t' => result.push_str("\\t"),
+            _ => result.push(c),
+        }
+    }
+    result.push('"');
+    result
+}
+
+fn quote_string(s: &str) -> String {
+    format!("\"{}\"", s)
+}
+
+impl DerivationData {
+    pub fn generate_aterm(&self) -> String {
+        let mut output_entries = Vec::new();
+        for (name, info) in &self.outputs {
+            output_entries.push(format!(
+                "({},{},{},{})",
+                quote_string(name),
+                quote_string(&info.path),
+                quote_string(&info.hash_algo),
+                quote_string(&info.hash),
+            ));
+        }
+        let outputs = output_entries.join(",");
+
+        let mut input_drv_entries = Vec::new();
+        for (drv_path, output_names) in &self.input_drvs {
+            let sorted_outs: Vec<String> = output_names.iter().map(|s| quote_string(s)).collect();
+            let out_list = format!("[{}]", sorted_outs.join(","));
+            input_drv_entries.push(format!("({},{})", quote_string(drv_path), out_list));
+        }
+        let input_drvs = input_drv_entries.join(",");
+
+        let input_srcs: Vec<String> = self.input_srcs.iter().map(|s| quote_string(s)).collect();
+        let input_srcs = input_srcs.join(",");
+
+        let args: Vec<String> = self.args.iter().map(|s| escape_string(s)).collect();
+        let args = args.join(",");
+
+        let mut env_entries: Vec<String> = Vec::new();
+        for (k, v) in &self.env {
+            env_entries.push(format!("({},{})", escape_string(k), escape_string(v)));
+        }
+
+        format!(
+            "Derive([{}],[{}],[{}],{},{},[{}],[{}])",
+            outputs,
+            input_drvs,
+            input_srcs,
+            quote_string(&self.platform),
+            escape_string(&self.builder),
+            args,
+            env_entries.join(","),
+        )
+    }
+
+    pub fn generate_aterm_modulo(&self, input_drv_hashes: &BTreeMap<String, String>) -> String {
+        let mut output_entries = Vec::new();
+        for (name, info) in &self.outputs {
+            output_entries.push(format!(
+                "({},{},{},{})",
+                quote_string(name),
+                quote_string(&info.path),
+                quote_string(&info.hash_algo),
+                quote_string(&info.hash),
+            ));
+        }
+        let outputs = output_entries.join(",");
+
+        let mut input_drv_entries = Vec::new();
+        for (drv_hash, outputs_csv) in input_drv_hashes {
+            let mut sorted_outs: Vec<&str> = outputs_csv.split(',').collect();
+            sorted_outs.sort();
+            let out_list: Vec<String> = sorted_outs.iter().map(|s| quote_string(s)).collect();
+            let out_list = format!("[{}]", out_list.join(","));
+            input_drv_entries.push(format!("({},{})", quote_string(drv_hash), out_list));
+        }
+        let input_drvs = input_drv_entries.join(",");
+
+        let input_srcs: Vec<String> = self.input_srcs.iter().map(|s| quote_string(s)).collect();
+        let input_srcs = input_srcs.join(",");
+
+        let args: Vec<String> = self.args.iter().map(|s| escape_string(s)).collect();
+        let args = args.join(",");
+
+        let mut env_entries: Vec<String> = Vec::new();
+        for (k, v) in &self.env {
+            env_entries.push(format!("({},{})", escape_string(k), escape_string(v)));
+        }
+
+        format!(
+            "Derive([{}],[{}],[{}],{},{},[{}],[{}])",
+            outputs,
+            input_drvs,
+            input_srcs,
+            quote_string(&self.platform),
+            escape_string(&self.builder),
+            args,
+            env_entries.join(","),
+        )
+    }
+
+    pub fn collect_references(&self) -> Vec<String> {
+        let mut refs = BTreeSet::new();
+        for src in &self.input_srcs {
+            refs.insert(src.clone());
+        }
+        for drv_path in self.input_drvs.keys() {
+            refs.insert(drv_path.clone());
+        }
+        refs.into_iter().collect()
+    }
+}

nix-js/src/disassembler.rs

@@ -0,0 +1,354 @@
+use std::fmt::Write;
+
+use colored::Colorize;
+use num_enum::TryFromPrimitive;
+
+use crate::bytecode::{Bytecode, Constant, Op};
+
+pub(crate) trait DisassemblerContext {
+    fn lookup_string(&self, id: u32) -> &str;
+    fn lookup_constant(&self, id: u32) -> &Constant;
+}
+
+pub(crate) struct Disassembler<'a, Ctx> {
+    code: &'a [u8],
+    ctx: &'a Ctx,
+    pos: usize,
+}
+
+impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
+    pub fn new(bytecode: &'a Bytecode, ctx: &'a Ctx) -> Self {
+        Self {
+            code: &bytecode.code,
+            ctx,
+            pos: 0,
+        }
+    }
+
+    fn read_u8(&mut self) -> u8 {
+        let b = self.code[self.pos];
+        self.pos += 1;
+        b
+    }
+
+    fn read_u16(&mut self) -> u16 {
+        let bytes = self.code[self.pos..self.pos + 2]
+            .try_into()
+            .expect("no enough bytes");
+        self.pos += 2;
+        u16::from_le_bytes(bytes)
+    }
+
+    fn read_u32(&mut self) -> u32 {
+        let bytes = self.code[self.pos..self.pos + 4]
+            .try_into()
+            .expect("no enough bytes");
+        self.pos += 4;
+        u32::from_le_bytes(bytes)
+    }
+
+    fn read_i32(&mut self) -> i32 {
+        let bytes = self.code[self.pos..self.pos + 4]
+            .try_into()
+            .expect("no enough bytes");
+        self.pos += 4;
+        i32::from_le_bytes(bytes)
+    }
+
+    pub fn disassemble(&mut self) -> String {
+        self.disassemble_impl(false)
+    }
+
+    pub fn disassemble_colored(&mut self) -> String {
+        self.disassemble_impl(true)
+    }
+
+    fn disassemble_impl(&mut self, color: bool) -> String {
+        let mut out = String::new();
+        if color {
+            let _ = writeln!(out, "{}", "=== Bytecode Disassembly ===".bold().white());
+            let _ = writeln!(
+                out,
+                "{} {}",
+                "Length:".white(),
+                format!("{} bytes", self.code.len()).cyan()
+            );
+        } else {
+            let _ = writeln!(out, "=== Bytecode Disassembly ===");
+            let _ = writeln!(out, "Length: {} bytes", self.code.len());
+        }
+
+        while self.pos < self.code.len() {
+            let start_pos = self.pos;
+            let op_byte = self.read_u8();
+            let (mnemonic, args) = self.decode_instruction(op_byte, start_pos);
+
+            let bytes_slice = &self.code[start_pos + 1..self.pos];
+
+            for (i, chunk) in bytes_slice.chunks(4).enumerate() {
+                let bytes_str = {
+                    let mut temp = String::new();
+                    if i == 0 {
+                        let _ = write!(&mut temp, "{:02x}", self.code[start_pos]);
+                    } else {
+                        let _ = write!(&mut temp, "  ");
+                    }
+                    for b in chunk.iter() {
+                        let _ = write!(&mut temp, " {:02x}", b);
+                    }
+                    temp
+                };
+
+                if i == 0 {
+                    if color {
+                        let sep = if args.is_empty() { "" } else { " " };
+                        let _ = writeln!(
+                            out,
+                            "{}  {:<14} | {}{}{}",
+                            format!("{:04x}", start_pos).dimmed(),
+                            bytes_str.green(),
+                            mnemonic.yellow().bold(),
+                            sep,
+                            args.cyan()
+                        );
+                    } else {
+                        let op_str = if args.is_empty() {
+                            mnemonic.to_string()
+                        } else {
+                            format!("{} {}", mnemonic, args)
+                        };
+                        let _ = writeln!(out, "{:04x}  {:<14} | {}", start_pos, bytes_str, op_str);
+                    }
+                } else {
+                    let extra_width = start_pos.ilog2() >> 4;
+                    if color {
+                        let _ = write!(out, "    ");
+                        for _ in 0..extra_width {
+                            let _ = write!(out, " ");
+                        }
+                        let _ = writeln!(out, "  {:<14} |", bytes_str.green());
+                    } else {
+                        let _ = write!(out, "    ");
+                        for _ in 0..extra_width {
+                            let _ = write!(out, " ");
+                        }
+                        let _ = writeln!(out, "  {:<14} |", bytes_str);
+                    }
+                }
+            }
+        }
+        out
+    }
+
+    fn decode_instruction(&mut self, op_byte: u8, current_pc: usize) -> (&'static str, String) {
+        let op = Op::try_from_primitive(op_byte).expect("invalid op code");
+
+        match op {
+            Op::PushConst => {
+                let idx = self.read_u32();
+                let val = self.ctx.lookup_constant(idx);
+                let val_str = match val {
+                    Constant::Int(i) => format!("Int({})", i),
+                    Constant::Float(f) => format!("Float(bits: {})", f),
+                };
+                ("PushConst", format!("@{} ({})", idx, val_str))
+            }
+            Op::PushString => {
+                let idx = self.read_u32();
+                let s = self.ctx.lookup_string(idx);
+                let len = s.len();
+                let mut s_fmt = format!("{:?}", s);
+                if s_fmt.len() > 60 {
+                    s_fmt.truncate(57);
+                    #[allow(clippy::unwrap_used)]
+                    write!(s_fmt, "...\" (total {len} bytes)").unwrap();
+                }
+                ("PushString", format!("@{} {}", idx, s_fmt))
+            }
+            Op::PushNull => ("PushNull", String::new()),
+            Op::PushTrue => ("PushTrue", String::new()),
+            Op::PushFalse => ("PushFalse", String::new()),
+
+            Op::LoadLocal => {
+                let idx = self.read_u32();
+                ("LoadLocal", format!("[{}]", idx))
+            }
+            Op::LoadOuter => {
+                let depth = self.read_u8();
+                let idx = self.read_u32();
+                ("LoadOuter", format!("depth={} [{}]", depth, idx))
+            }
+            Op::StoreLocal => {
+                let idx = self.read_u32();
+                ("StoreLocal", format!("[{}]", idx))
+            }
+            Op::AllocLocals => {
+                let count = self.read_u32();
+                ("AllocLocals", format!("count={}", count))
+            }
+
+            Op::MakeThunk => {
+                let offset = self.read_u32();
+                let label_idx = self.read_u32();
+                let label = self.ctx.lookup_string(label_idx);
+                ("MakeThunk", format!("-> {:04x} label={}", offset, label))
+            }
+            Op::MakeClosure => {
+                let offset = self.read_u32();
+                let slots = self.read_u32();
+                ("MakeClosure", format!("-> {:04x} slots={}", offset, slots))
+            }
+            Op::MakePatternClosure => {
+                let offset = self.read_u32();
+                let slots = self.read_u32();
+                let req_count = self.read_u16();
+                let opt_count = self.read_u16();
+                let ellipsis = self.read_u8() != 0;
+
+                let mut arg_str = format!(
+                    "-> {:04x} slots={} req={} opt={} ...={})",
+                    offset, slots, req_count, opt_count, ellipsis
+                );
+
+                arg_str.push_str(" Args=[");
+                for _ in 0..req_count {
+                    let idx = self.read_u32();
+                    arg_str.push_str(&format!("Req({}) ", self.ctx.lookup_string(idx)));
+                }
+                for _ in 0..opt_count {
+                    let idx = self.read_u32();
+                    arg_str.push_str(&format!("Opt({}) ", self.ctx.lookup_string(idx)));
+                }
+
+                let total_args = req_count + opt_count;
+                for _ in 0..total_args {
+                    let _name_idx = self.read_u32();
+                    let _span_id = self.read_u32();
+                }
+                arg_str.push(']');
+
+                ("MakePatternClosure", arg_str)
+            }
+
+            Op::Call => {
+                let span_id = self.read_u32();
+                ("Call", format!("span={}", span_id))
+            }
+            Op::CallNoSpan => ("CallNoSpan", String::new()),
+
+            Op::MakeAttrs => {
+                let count = self.read_u32();
+                ("MakeAttrs", format!("size={}", count))
+            }
+            Op::MakeAttrsDyn => {
+                let static_count = self.read_u32();
+                let dyn_count = self.read_u32();
+                (
+                    "MakeAttrsDyn",
+                    format!("static={} dyn={}", static_count, dyn_count),
+                )
+            }
+            Op::MakeEmptyAttrs => ("MakeEmptyAttrs", String::new()),
+
+            Op::Select => {
+                let path_len = self.read_u16();
+                let span_id = self.read_u32();
+                ("Select", format!("path_len={} span={}", path_len, span_id))
+            }
+            Op::SelectDefault => {
+                let path_len = self.read_u16();
+                let span_id = self.read_u32();
+                (
+                    "SelectDefault",
+                    format!("path_len={} span={}", path_len, span_id),
+                )
+            }
+            Op::HasAttr => {
+                let path_len = self.read_u16();
+                ("HasAttr", format!("path_len={}", path_len))
+            }
+
+            Op::MakeList => {
+                let count = self.read_u32();
+                ("MakeList", format!("size={}", count))
+            }
+
+            Op::OpAdd => ("OpAdd", String::new()),
+            Op::OpSub => ("OpSub", String::new()),
+            Op::OpMul => ("OpMul", String::new()),
+            Op::OpDiv => ("OpDiv", String::new()),
+            Op::OpEq => ("OpEq", String::new()),
+            Op::OpNeq => ("OpNeq", String::new()),
+            Op::OpLt => ("OpLt", String::new()),
+            Op::OpGt => ("OpGt", String::new()),
+            Op::OpLeq => ("OpLeq", String::new()),
+            Op::OpGeq => ("OpGeq", String::new()),
+            Op::OpConcat => ("OpConcat", String::new()),
+            Op::OpUpdate => ("OpUpdate", String::new()),
+            Op::OpNeg => ("OpNeg", String::new()),
+            Op::OpNot => ("OpNot", String::new()),
+
+            Op::ForceBool => ("ForceBool", String::new()),
+
+            Op::JumpIfFalse => {
+                let offset = self.read_i32();
+                let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
+                (
+                    "JumpIfFalse",
+                    format!("-> {:04x} offset={}", target, offset),
+                )
+            }
+            Op::JumpIfTrue => {
+                let offset = self.read_i32();
+                let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
+                ("JumpIfTrue", format!("-> {:04x} offset={}", target, offset))
+            }
+            Op::Jump => {
+                let offset = self.read_i32();
+                let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
+                ("Jump", format!("-> {:04x} offset={}", target, offset))
+            }
+
+            Op::ConcatStrings => {
+                let count = self.read_u16();
+                let force = self.read_u8();
+                ("ConcatStrings", format!("count={} force={}", count, force))
+            }
+            Op::ResolvePath => ("ResolvePath", String::new()),
+            Op::Assert => {
+                let raw_idx = self.read_u32();
+                let span_id = self.read_u32();
+                ("Assert", format!("text_id={} span={}", raw_idx, span_id))
+            }
+            Op::PushWith => ("PushWith", String::new()),
+            Op::PopWith => ("PopWith", String::new()),
+            Op::WithLookup => {
+                let idx = self.read_u32();
+                let name = self.ctx.lookup_string(idx);
+                ("WithLookup", format!("{:?}", name))
+            }
+
+            Op::LoadBuiltins => ("LoadBuiltins", String::new()),
+            Op::LoadBuiltin => {
+                let idx = self.read_u32();
+                let name = self.ctx.lookup_string(idx);
+                ("LoadBuiltin", format!("{:?}", name))
+            }
+            Op::MkPos => {
+                let span_id = self.read_u32();
+                ("MkPos", format!("id={}", span_id))
+            }
+            Op::LoadReplBinding => {
+                let idx = self.read_u32();
+                let name = self.ctx.lookup_string(idx);
+                ("LoadReplBinding", format!("{:?}", name))
+            }
+            Op::LoadScopedBinding => {
+                let idx = self.read_u32();
+                let name = self.ctx.lookup_string(idx);
+                ("LoadScopedBinding", format!("{:?}", name))
+            }
+            Op::Return => ("Return", String::new()),
+        }
+    }
+}

nix-js/src/error.rs

@@ -1,5 +1,3 @@
-#![allow(unused_assignments)]
-
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
@@ -21,6 +19,8 @@ pub enum SourceType {
     Repl(Arc<PathBuf>),
     /// file
     File(Arc<PathBuf>),
+    /// virtual (name, no path)
+    Virtual(Arc<str>),
 }
 
 #[derive(Clone, Debug)]
@@ -44,6 +44,13 @@ impl From<Source> for NamedSource<Arc<str>> {
 }
 
 impl Source {
+    pub fn new_file(path: PathBuf) -> std::io::Result<Self> {
+        Ok(Source {
+            src: std::fs::read_to_string(&path)?.into(),
+            ty: crate::error::SourceType::File(Arc::new(path)),
+        })
+    }
+
     pub fn new_eval(src: String) -> Result<Self> {
         Ok(Self {
             ty: std::env::current_dir()
@@ -64,6 +71,13 @@ impl Source {
         })
     }
 
+    pub fn new_virtual(name: Arc<str>, src: String) -> Self {
+        Self {
+            ty: SourceType::Virtual(name),
+            src: src.into(),
+        }
+    }
+
     pub fn get_dir(&self) -> &Path {
         use SourceType::*;
         match &self.ty {
@@ -72,6 +86,7 @@ impl Source {
                 .as_path()
                 .parent()
                 .expect("source file must have a parent dir"),
+            Virtual(_) => Path::new("/"),
         }
     }
 
@@ -80,6 +95,7 @@ impl Source {
             SourceType::Eval(_) => "«eval»".into(),
             SourceType::Repl(_) => "«repl»".into(),
             SourceType::File(path) => path.as_os_str().to_string_lossy().to_string(),
+            SourceType::Virtual(name) => name.to_string(),
         }
     }
 }
@@ -276,43 +292,32 @@ fn parse_frames(stack: &str, ctx: &impl RuntimeContext) -> Vec<NixStackFrame> {
     let mut frames = Vec::new();
 
     for line in stack.lines() {
-        // Format: NIX_STACK_FRAME:source_id:start:end[:extra_data]
+        // Format: NIX_STACK_FRAME:span_id:message
         let Some(rest) = line.strip_prefix("NIX_STACK_FRAME:") else {
             continue;
         };
-        let parts: Vec<&str> = rest.splitn(4, ':').collect();
+        let parts: Vec<&str> = rest.splitn(2, ':').collect();
 
-        if parts.len() < 3 {
+        if parts.is_empty() {
             continue;
         }
 
-        let src = match parts[0].parse() {
-            Ok(id) => ctx.get_source(id),
-            Err(_) => continue,
-        };
-        let start: u32 = match parts[1].parse() {
-            Ok(v) => v,
-            Err(_) => continue,
-        };
-        let end: u32 = match parts[2].parse() {
-            Ok(v) => v,
+        let span_id: usize = match parts[0].parse() {
+            Ok(id) => id,
             Err(_) => continue,
         };
+        let (source_id, span) = ctx.get_span(span_id);
+        let src = ctx.get_source(source_id);
 
-        let span = rnix::TextRange::new(rnix::TextSize::from(start), rnix::TextSize::from(end));
-
-        let message = {
-            if parts.len() == 4 {
-                parts[3].to_string()
+        let message = if parts.len() == 2 {
+            parts[1].to_string()
         } else {
             String::new()
-            }
         };
 
         frames.push(NixStackFrame { span, message, src });
     }
 
-    // Deduplicate consecutive identical frames
     frames.dedup_by(|a, b| a.span == b.span && a.message == b.message);
 
     frames

nix-js/src/fetcher.rs

@@ -1,16 +1,18 @@
 use deno_core::OpState;
+use deno_core::ToV8;
 use deno_core::op2;
-use serde::Serialize;
+use nix_compat::nixhash::HashAlgo;
+use nix_compat::nixhash::NixHash;
 use tracing::{debug, info, warn};
 
 use crate::runtime::OpStateExt;
 use crate::runtime::RuntimeContext;
+use crate::store::Store as _;
 
 mod archive;
 pub(crate) mod cache;
 mod download;
 mod git;
-mod hg;
 mod metadata_cache;
 
 pub use cache::FetcherCache;
@@ -18,22 +20,21 @@ pub use download::Downloader;
 pub use metadata_cache::MetadataCache;
 
 use crate::nar;
-use crate::runtime::NixError;
+use crate::runtime::NixRuntimeError;
 
-#[derive(Serialize)]
+#[derive(ToV8)]
 pub struct FetchUrlResult {
     pub store_path: String,
     pub hash: String,
 }
 
-#[derive(Serialize)]
+#[derive(ToV8)]
 pub struct FetchTarballResult {
     pub store_path: String,
-    pub hash: String,
     pub nar_hash: String,
 }
 
-#[derive(Serialize)]
+#[derive(ToV8)]
 pub struct FetchGitResult {
     pub out_path: String,
     pub rev: String,
@@ -45,31 +46,22 @@ pub struct FetchGitResult {
     pub nar_hash: Option<String>,
 }
 
-#[derive(Serialize)]
-pub struct FetchHgResult {
-    pub out_path: String,
-    pub branch: String,
-    pub rev: String,
-    pub short_rev: String,
-    pub rev_count: u64,
-}
-
 #[op2]
-#[serde]
 pub fn op_fetch_url<Ctx: RuntimeContext>(
     state: &mut OpState,
     #[string] url: String,
     #[string] expected_hash: Option<String>,
     #[string] name: Option<String>,
     executable: bool,
-) -> Result<FetchUrlResult, NixError> {
+) -> Result<FetchUrlResult, NixRuntimeError> {
     let _span = tracing::info_span!("op_fetch_url", url = %url).entered();
     info!("fetchurl started");
 
     let file_name =
         name.unwrap_or_else(|| url.rsplit('/').next().unwrap_or("download").to_string());
 
-    let metadata_cache = MetadataCache::new(3600).map_err(|e| NixError::from(e.to_string()))?;
+    let metadata_cache =
+        MetadataCache::new(3600).map_err(|e| NixRuntimeError::from(e.to_string()))?;
 
     let input = serde_json::json!({
         "type": "file",
@@ -80,7 +72,7 @@ pub fn op_fetch_url<Ctx: RuntimeContext>(
 
     if let Some(cached_entry) = metadata_cache
         .lookup(&input)
-        .map_err(|e| NixError::from(e.to_string()))?
+        .map_err(|e| NixRuntimeError::from(e.to_string()))?
     {
         let cached_hash = cached_entry
             .info
@@ -112,16 +104,16 @@ pub fn op_fetch_url<Ctx: RuntimeContext>(
     let downloader = Downloader::new();
     let data = downloader
         .download(&url)
-        .map_err(|e| NixError::from(e.to_string()))?;
+        .map_err(|e| NixRuntimeError::from(e.to_string()))?;
 
     info!(bytes = data.len(), "Download complete");
 
-    let hash = crate::nix_hash::sha256_hex(&String::from_utf8_lossy(&data));
+    let hash = crate::nix_utils::sha256_hex(&data);
 
     if let Some(ref expected) = expected_hash {
         let normalized_expected = normalize_hash(expected);
         if hash != normalized_expected {
-            return Err(NixError::from(format!(
+            return Err(NixRuntimeError::from(format!(
                 "hash mismatch for '{}': expected {}, got {}",
                 url, normalized_expected, hash
             )));
@@ -132,7 +124,7 @@ pub fn op_fetch_url<Ctx: RuntimeContext>(
     let store = ctx.get_store();
     let store_path = store
         .add_to_store(&file_name, &data, false, vec![])
-        .map_err(|e| NixError::from(e.to_string()))?;
+        .map_err(|e| NixRuntimeError::from(e.to_string()))?;
 
     info!(store_path = %store_path, "Added to store");
 
@@ -153,25 +145,24 @@ pub fn op_fetch_url<Ctx: RuntimeContext>(
 
     metadata_cache
         .add(&input, &info, &store_path, true)
-        .map_err(|e| NixError::from(e.to_string()))?;
+        .map_err(|e| NixRuntimeError::from(e.to_string()))?;
 
     Ok(FetchUrlResult { store_path, hash })
 }
 
 #[op2]
-#[serde]
 pub fn op_fetch_tarball<Ctx: RuntimeContext>(
     state: &mut OpState,
     #[string] url: String,
-    #[string] expected_hash: Option<String>,
-    #[string] expected_nar_hash: Option<String>,
     #[string] name: Option<String>,
-) -> Result<FetchTarballResult, NixError> {
+    #[string] sha256: Option<String>,
+) -> Result<FetchTarballResult, NixRuntimeError> {
     let _span = tracing::info_span!("op_fetch_tarball", url = %url).entered();
     info!("fetchTarball started");
 
     let dir_name = name.unwrap_or_else(|| "source".to_string());
-    let metadata_cache = MetadataCache::new(3600).map_err(|e| NixError::from(e.to_string()))?;
+    let metadata_cache =
+        MetadataCache::new(3600).map_err(|e| NixRuntimeError::from(e.to_string()))?;
 
     let input = serde_json::json!({
         "type": "tarball",
@@ -179,28 +170,31 @@ pub fn op_fetch_tarball<Ctx: RuntimeContext>(
         "name": dir_name,
     });
 
+    let expected_sha256 = sha256
+        .map(
+            |ref sha256| match NixHash::from_str(sha256, Some(HashAlgo::Sha256)) {
+                Ok(NixHash::Sha256(digest)) => Ok(digest),
+                _ => Err(format!("fetchTarball: invalid sha256 '{sha256}'")),
+            },
+        )
+        .transpose()?;
+    let expected_hex = expected_sha256.map(hex::encode);
+
     if let Some(cached_entry) = metadata_cache
         .lookup(&input)
-        .map_err(|e| NixError::from(e.to_string()))?
+        .map_err(|e| NixRuntimeError::from(e.to_string()))?
     {
         let cached_nar_hash = cached_entry
             .info
             .get("nar_hash")
             .and_then(|v| v.as_str())
             .unwrap_or("");
-        let cached_tarball_hash = cached_entry
-            .info
-            .get("tarball_hash")
-            .and_then(|v| v.as_str())
-            .unwrap_or("");
 
-        if let Some(ref expected_nar) = expected_nar_hash {
-            let normalized_expected = normalize_hash(expected_nar);
-            if cached_nar_hash == normalized_expected {
+        if let Some(ref hex) = expected_hex {
+            if cached_nar_hash == hex {
                 info!("Cache hit");
                 return Ok(FetchTarballResult {
                     store_path: cached_entry.store_path.clone(),
-                    hash: cached_tarball_hash.to_string(),
                     nar_hash: cached_nar_hash.to_string(),
                 });
             }
@@ -208,7 +202,6 @@ pub fn op_fetch_tarball<Ctx: RuntimeContext>(
             info!("Cache hit (no hash check)");
             return Ok(FetchTarballResult {
                 store_path: cached_entry.store_path.clone(),
-                hash: cached_tarball_hash.to_string(),
                 nar_hash: cached_nar_hash.to_string(),
             });
         }
@@ -218,77 +211,59 @@ pub fn op_fetch_tarball<Ctx: RuntimeContext>(
     let downloader = Downloader::new();
     let data = downloader
         .download(&url)
-        .map_err(|e| NixError::from(e.to_string()))?;
+        .map_err(|e| NixRuntimeError::from(e.to_string()))?;
 
     info!(bytes = data.len(), "Download complete");
 
-    let tarball_hash = crate::nix_hash::sha256_hex(&String::from_utf8_lossy(&data));
-
-    if let Some(ref expected) = expected_hash {
-        let normalized_expected = normalize_hash(expected);
-        if tarball_hash != normalized_expected {
-            return Err(NixError::from(format!(
-                "Tarball hash mismatch for '{}': expected {}, got {}",
-                url, normalized_expected, tarball_hash
-            )));
-        }
-    }
-
     info!("Extracting tarball");
-    let cache = FetcherCache::new().map_err(|e| NixError::from(e.to_string()))?;
-    let (extracted_path, _temp_dir) = cache
-        .extract_tarball_to_temp(&data)
-        .map_err(|e| NixError::from(e.to_string()))?;
+    let (extracted_path, _temp_dir) = archive::extract_tarball_to_temp(&data)
+        .map_err(|e| NixRuntimeError::from(e.to_string()))?;
 
     info!("Computing NAR hash");
     let nar_hash =
-        nar::compute_nar_hash(&extracted_path).map_err(|e| NixError::from(e.to_string()))?;
+        nar::compute_nar_hash(&extracted_path).map_err(|e| NixRuntimeError::from(e.to_string()))?;
+    let nar_hash_hex = hex::encode(nar_hash);
 
     debug!(
-        tarball_hash = %tarball_hash,
-        nar_hash = %nar_hash,
+        nar_hash = %nar_hash_hex,
         "Hash computation complete"
     );
 
-    if let Some(ref expected) = expected_nar_hash {
-        let normalized_expected = normalize_hash(expected);
-        if nar_hash != normalized_expected {
-            return Err(NixError::from(format!(
-                "NAR hash mismatch for '{}': expected {}, got {}",
-                url, normalized_expected, nar_hash
+    if let Some(ref expected) = expected_hex
+        && nar_hash_hex != *expected
+    {
+        return Err(NixRuntimeError::from(format!(
+            "Tarball hash mismatch for '{}': expected {}, got {}",
+            url, expected, nar_hash_hex
         )));
     }
-    }
 
     info!("Adding to store");
     let ctx: &Ctx = state.get_ctx();
     let store = ctx.get_store();
     let store_path = store
         .add_to_store_from_path(&dir_name, &extracted_path, vec![])
-        .map_err(|e| NixError::from(e.to_string()))?;
+        .map_err(|e| NixRuntimeError::from(e.to_string()))?;
 
     info!(store_path = %store_path, "Added to store");
 
     let info = serde_json::json!({
-        "tarball_hash": tarball_hash,
-        "nar_hash": nar_hash,
+        "nar_hash": nar_hash_hex,
         "url": url,
     });
 
-    let immutable = expected_nar_hash.is_some();
+    let immutable = expected_sha256.is_some();
     metadata_cache
         .add(&input, &info, &store_path, immutable)
-        .map_err(|e| NixError::from(e.to_string()))?;
+        .map_err(|e| NixRuntimeError::from(e.to_string()))?;
 
     Ok(FetchTarballResult {
         store_path,
-        hash: tarball_hash,
-        nar_hash,
+        nar_hash: nar_hash_hex,
     })
 }
 
 #[op2]
-#[serde]
 pub fn op_fetch_git<Ctx: RuntimeContext>(
     state: &mut OpState,
     #[string] url: String,
@@ -298,10 +273,10 @@ pub fn op_fetch_git<Ctx: RuntimeContext>(
     submodules: bool,
     all_refs: bool,
     #[string] name: Option<String>,
-) -> Result<FetchGitResult, NixError> {
+) -> Result<FetchGitResult, NixRuntimeError> {
     let _span = tracing::info_span!("op_fetch_git", url = %url).entered();
     info!("fetchGit started");
-    let cache = FetcherCache::new().map_err(|e| NixError::from(e.to_string()))?;
+    let cache = FetcherCache::new().map_err(|e| NixRuntimeError::from(e.to_string()))?;
     let dir_name = name.unwrap_or_else(|| "source".to_string());
 
     let ctx: &Ctx = state.get_ctx();
@@ -318,65 +293,24 @@ pub fn op_fetch_git<Ctx: RuntimeContext>(
         all_refs,
         &dir_name,
     )
-    .map_err(|e| NixError::from(e.to_string()))
-}
-
-#[op2]
-#[serde]
-pub fn op_fetch_hg(
-    #[string] url: String,
-    #[string] rev: Option<String>,
-    #[string] name: Option<String>,
-) -> Result<FetchHgResult, NixError> {
-    let cache = FetcherCache::new().map_err(|e| NixError::from(e.to_string()))?;
-    let dir_name = name.unwrap_or_else(|| "source".to_string());
-
-    hg::fetch_hg(&cache, &url, rev.as_deref(), &dir_name).map_err(|e| NixError::from(e.to_string()))
+    .map_err(|e| NixRuntimeError::from(e.to_string()))
 }
 
 fn normalize_hash(hash: &str) -> String {
+    use base64::prelude::*;
     if hash.starts_with("sha256-")
         && let Some(b64) = hash.strip_prefix("sha256-")
-        && let Ok(bytes) = base64_decode(b64)
+        && let Ok(bytes) = BASE64_STANDARD.decode(b64)
     {
         return hex::encode(bytes);
     }
     hash.to_string()
 }
 
-fn base64_decode(input: &str) -> Result<Vec<u8>, String> {
-    const ALPHABET: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-
-    let input = input.trim_end_matches('=');
-    let mut output = Vec::with_capacity(input.len() * 3 / 4);
-
-    let mut buffer = 0u32;
-    let mut bits = 0;
-
-    for c in input.bytes() {
-        let value = ALPHABET
-            .iter()
-            .position(|&x| x == c)
-            .ok_or_else(|| format!("Invalid base64 character: {}", c as char))?;
-
-        buffer = (buffer << 6) | (value as u32);
-        bits += 6;
-
-        if bits >= 8 {
-            bits -= 8;
-            output.push((buffer >> bits) as u8);
-            buffer &= (1 << bits) - 1;
-        }
-    }
-
-    Ok(output)
-}
-
 pub fn register_ops<Ctx: RuntimeContext>() -> Vec<deno_core::OpDecl> {
     vec![
         op_fetch_url::<Ctx>(),
         op_fetch_tarball::<Ctx>(),
         op_fetch_git::<Ctx>(),
-        op_fetch_hg(),
     ]
 }

nix-js/src/fetcher/archive.rs

@@ -1,5 +1,6 @@
-use std::fs::{self, File};
+use std::fs;
 use std::io::Cursor;
+use std::os::unix::ffi::OsStrExt;
 use std::path::{Path, PathBuf};
 
 use flate2::read::GzDecoder;
@@ -10,7 +11,6 @@ pub enum ArchiveFormat {
     TarXz,
     TarBz2,
     Tar,
-    Zip,
 }
 
 impl ArchiveFormat {
@@ -27,9 +27,6 @@ impl ArchiveFormat {
         if url.ends_with(".tar") {
             return ArchiveFormat::Tar;
         }
-        if url.ends_with(".zip") {
-            return ArchiveFormat::Zip;
-        }
 
         if data.len() >= 2 && data[0] == 0x1f && data[1] == 0x8b {
             return ArchiveFormat::TarGz;
@@ -40,15 +37,12 @@ impl ArchiveFormat {
         if data.len() >= 3 && &data[0..3] == b"BZh" {
             return ArchiveFormat::TarBz2;
         }
-        if data.len() >= 4 && &data[0..4] == b"PK\x03\x04" {
-            return ArchiveFormat::Zip;
-        }
 
         ArchiveFormat::TarGz
     }
 }
 
-pub fn extract_archive(data: &[u8], dest: &Path) -> Result<PathBuf, ArchiveError> {
+pub fn extract_tarball(data: &[u8], dest: &Path) -> Result<PathBuf, ArchiveError> {
     let format = ArchiveFormat::detect("", data);
 
     let temp_dir = dest.join("_extract_temp");
@@ -59,7 +53,6 @@ pub fn extract_archive(data: &[u8], dest: &Path) -> Result<PathBuf, ArchiveError
         ArchiveFormat::TarXz => extract_tar_xz(data, &temp_dir)?,
         ArchiveFormat::TarBz2 => extract_tar_bz2(data, &temp_dir)?,
         ArchiveFormat::Tar => extract_tar(data, &temp_dir)?,
-        ArchiveFormat::Zip => extract_zip(data, &temp_dir)?,
     }
 
     strip_single_toplevel(&temp_dir, dest)
@@ -92,40 +85,10 @@ fn extract_tar(data: &[u8], dest: &Path) -> Result<(), ArchiveError> {
     Ok(())
 }
 
-fn extract_zip(data: &[u8], dest: &Path) -> Result<(), ArchiveError> {
-    let cursor = Cursor::new(data);
-    let mut archive = zip::ZipArchive::new(cursor)?;
-
-    for i in 0..archive.len() {
-        let mut file = archive.by_index(i)?;
-        let outpath = dest.join(file.mangled_name());
-
-        if file.is_dir() {
-            fs::create_dir_all(&outpath)?;
-        } else {
-            if let Some(parent) = outpath.parent() {
-                fs::create_dir_all(parent)?;
-            }
-            let mut outfile = File::create(&outpath)?;
-            std::io::copy(&mut file, &mut outfile)?;
-        }
-
-        #[cfg(unix)]
-        {
-            use std::os::unix::fs::PermissionsExt;
-            if let Some(mode) = file.unix_mode() {
-                fs::set_permissions(&outpath, fs::Permissions::from_mode(mode))?;
-            }
-        }
-    }
-
-    Ok(())
-}
-
 fn strip_single_toplevel(temp_dir: &Path, dest: &Path) -> Result<PathBuf, ArchiveError> {
     let entries: Vec<_> = fs::read_dir(temp_dir)?
         .filter_map(|e| e.ok())
-        .filter(|e| !e.file_name().to_string_lossy().starts_with('.'))
+        .filter(|e| e.file_name().as_os_str().as_bytes()[0] != b'.')
         .collect();
 
     let source_dir = if entries.len() == 1 && entries[0].file_type()?.is_dir() {
@@ -182,17 +145,21 @@ fn copy_dir_recursive(src: &Path, dst: &Path) -> Result<(), std::io::Error> {
     Ok(())
 }
 
+pub fn extract_tarball_to_temp(data: &[u8]) -> Result<(PathBuf, tempfile::TempDir), ArchiveError> {
+    let temp_dir = tempfile::tempdir()?;
+    let extracted_path = extract_tarball(data, temp_dir.path())?;
+    Ok((extracted_path, temp_dir))
+}
+
 #[derive(Debug)]
 pub enum ArchiveError {
     IoError(std::io::Error),
-    ZipError(zip::result::ZipError),
 }
 
 impl std::fmt::Display for ArchiveError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
             ArchiveError::IoError(e) => write!(f, "I/O error: {}", e),
-            ArchiveError::ZipError(e) => write!(f, "ZIP error: {}", e),
         }
     }
 }
@@ -204,9 +171,3 @@ impl From<std::io::Error> for ArchiveError {
         ArchiveError::IoError(e)
     }
 }
-
-impl From<zip::result::ZipError> for ArchiveError {
-    fn from(e: zip::result::ZipError) -> Self {
-        ArchiveError::ZipError(e)
-    }
-}

nix-js/src/fetcher/cache.rs

@@ -1,36 +1,5 @@
 use std::fs;
-use std::path::{Path, PathBuf};
-
-use super::archive::ArchiveError;
-
-#[derive(Debug)]
-pub enum CacheError {
-    Io(std::io::Error),
-    Archive(ArchiveError),
-}
-
-impl std::fmt::Display for CacheError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            CacheError::Io(e) => write!(f, "I/O error: {}", e),
-            CacheError::Archive(e) => write!(f, "Archive error: {}", e),
-        }
-    }
-}
-
-impl std::error::Error for CacheError {}
-
-impl From<std::io::Error> for CacheError {
-    fn from(e: std::io::Error) -> Self {
-        CacheError::Io(e)
-    }
-}
-
-impl From<ArchiveError> for CacheError {
-    fn from(e: ArchiveError) -> Self {
-        CacheError::Archive(e)
-    }
-}
+use std::path::PathBuf;
 
 #[derive(Debug)]
 pub struct FetcherCache {
@@ -49,59 +18,12 @@ impl FetcherCache {
         Ok(Self { base_dir })
     }
 
-    pub fn make_store_path(&self, hash: &str, name: &str) -> PathBuf {
-        let short_hash = &hash[..32.min(hash.len())];
-        self.base_dir
-            .join("store")
-            .join(format!("{}-{}", short_hash, name))
-    }
-
     fn git_cache_dir(&self) -> PathBuf {
-        self.base_dir.join("gitv3")
-    }
-
-    fn hg_cache_dir(&self) -> PathBuf {
-        self.base_dir.join("hg")
-    }
-
-    fn hash_key(url: &str) -> String {
-        crate::nix_hash::sha256_hex(url)
+        self.base_dir.join("git")
     }
 
     pub fn get_git_bare(&self, url: &str) -> PathBuf {
-        let key = Self::hash_key(url);
+        let key = crate::nix_utils::sha256_hex(url.as_bytes());
         self.git_cache_dir().join(key)
     }
-
-    pub fn get_hg_bare(&self, url: &str) -> PathBuf {
-        let key = Self::hash_key(url);
-        self.hg_cache_dir().join(key)
-    }
-
-    pub fn extract_tarball_to_temp(
-        &self,
-        data: &[u8],
-    ) -> Result<(PathBuf, tempfile::TempDir), CacheError> {
-        let temp_dir = tempfile::tempdir()?;
-        let extracted_path = super::archive::extract_archive(data, temp_dir.path())?;
-        Ok((extracted_path, temp_dir))
-    }
-}
-
-pub fn copy_dir_recursive(src: &Path, dst: &Path) -> Result<(), std::io::Error> {
-    fs::create_dir_all(dst)?;
-
-    for entry in fs::read_dir(src)? {
-        let entry = entry?;
-        let path = entry.path();
-        let dest_path = dst.join(entry.file_name());
-
-        if path.is_dir() {
-            copy_dir_recursive(&path, &dest_path)?;
-        } else {
-            fs::copy(&path, &dest_path)?;
-        }
-    }
-
-    Ok(())
 }

nix-js/src/fetcher/download.rs

@@ -1,6 +1,7 @@
-use reqwest::blocking::Client;
 use std::time::Duration;
 
+use reqwest::blocking::Client;
+
 pub struct Downloader {
     client: Client,
 }

nix-js/src/fetcher/git.rs

@@ -31,8 +31,10 @@ pub fn fetch_git(
     let temp_dir = tempfile::tempdir()?;
     let checkout_dir = checkout_rev_to_temp(&bare_repo, &target_rev, submodules, temp_dir.path())?;
 
-    let nar_hash = crate::nar::compute_nar_hash(&checkout_dir)
-        .map_err(|e| GitError::NarHashError(e.to_string()))?;
+    let nar_hash = hex::encode(
+        crate::nar::compute_nar_hash(&checkout_dir)
+            .map_err(|e| GitError::NarHashError(e.to_string()))?,
+    );
 
     let store_path = store
         .add_to_store_from_path(name, &checkout_dir, vec![])

nix-js/src/fetcher/hg.rs

@@ -1,196 +0,0 @@
-use std::fs;
-use std::path::PathBuf;
-use std::process::Command;
-
-use super::FetchHgResult;
-use super::cache::FetcherCache;
-
-pub fn fetch_hg(
-    cache: &FetcherCache,
-    url: &str,
-    rev: Option<&str>,
-    name: &str,
-) -> Result<FetchHgResult, HgError> {
-    let bare_repo = cache.get_hg_bare(url);
-
-    if !bare_repo.exists() {
-        clone_repo(url, &bare_repo)?;
-    } else {
-        pull_repo(&bare_repo)?;
-    }
-
-    let target_rev = rev.unwrap_or("tip").to_string();
-    let resolved_rev = resolve_rev(&bare_repo, &target_rev)?;
-    let branch = get_branch(&bare_repo, &resolved_rev)?;
-
-    let checkout_dir = checkout_rev(&bare_repo, &resolved_rev, name, cache)?;
-
-    let rev_count = get_rev_count(&bare_repo, &resolved_rev)?;
-
-    let short_rev = if resolved_rev.len() >= 12 {
-        resolved_rev[..12].to_string()
-    } else {
-        resolved_rev.clone()
-    };
-
-    Ok(FetchHgResult {
-        out_path: checkout_dir.to_string_lossy().to_string(),
-        branch,
-        rev: resolved_rev,
-        short_rev,
-        rev_count,
-    })
-}
-
-fn clone_repo(url: &str, dest: &PathBuf) -> Result<(), HgError> {
-    fs::create_dir_all(dest.parent().unwrap_or(dest))?;
-
-    let output = Command::new("hg")
-        .args(["clone", "-U", url])
-        .arg(dest)
-        .env("HGPLAIN", "")
-        .output()?;
-
-    if !output.status.success() {
-        return Err(HgError::CommandFailed {
-            operation: "clone".to_string(),
-            message: String::from_utf8_lossy(&output.stderr).to_string(),
-        });
-    }
-
-    Ok(())
-}
-
-fn pull_repo(repo: &PathBuf) -> Result<(), HgError> {
-    let output = Command::new("hg")
-        .args(["pull"])
-        .current_dir(repo)
-        .env("HGPLAIN", "")
-        .output()?;
-
-    if !output.status.success() {
-        return Err(HgError::CommandFailed {
-            operation: "pull".to_string(),
-            message: String::from_utf8_lossy(&output.stderr).to_string(),
-        });
-    }
-
-    Ok(())
-}
-
-fn resolve_rev(repo: &PathBuf, rev: &str) -> Result<String, HgError> {
-    let output = Command::new("hg")
-        .args(["log", "-r", rev, "--template", "{node}"])
-        .current_dir(repo)
-        .env("HGPLAIN", "")
-        .output()?;
-
-    if !output.status.success() {
-        return Err(HgError::CommandFailed {
-            operation: "log".to_string(),
-            message: format!(
-                "Could not resolve rev '{}': {}",
-                rev,
-                String::from_utf8_lossy(&output.stderr)
-            ),
-        });
-    }
-
-    Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
-}
-
-fn get_branch(repo: &PathBuf, rev: &str) -> Result<String, HgError> {
-    let output = Command::new("hg")
-        .args(["log", "-r", rev, "--template", "{branch}"])
-        .current_dir(repo)
-        .env("HGPLAIN", "")
-        .output()?;
-
-    if !output.status.success() {
-        return Ok("default".to_string());
-    }
-
-    let branch = String::from_utf8_lossy(&output.stdout).trim().to_string();
-    if branch.is_empty() {
-        Ok("default".to_string())
-    } else {
-        Ok(branch)
-    }
-}
-
-fn checkout_rev(
-    bare_repo: &PathBuf,
-    rev: &str,
-    name: &str,
-    cache: &FetcherCache,
-) -> Result<PathBuf, HgError> {
-    let hash = crate::nix_hash::sha256_hex(&format!("{}:{}", bare_repo.display(), rev));
-    let checkout_dir = cache.make_store_path(&hash, name);
-
-    if checkout_dir.exists() {
-        return Ok(checkout_dir);
-    }
-
-    fs::create_dir_all(&checkout_dir)?;
-
-    let output = Command::new("hg")
-        .args(["archive", "-r", rev])
-        .arg(&checkout_dir)
-        .current_dir(bare_repo)
-        .env("HGPLAIN", "")
-        .output()?;
-
-    if !output.status.success() {
-        fs::remove_dir_all(&checkout_dir)?;
-        return Err(HgError::CommandFailed {
-            operation: "archive".to_string(),
-            message: String::from_utf8_lossy(&output.stderr).to_string(),
-        });
-    }
-
-    let hg_archival = checkout_dir.join(".hg_archival.txt");
-    if hg_archival.exists() {
-        fs::remove_file(&hg_archival)?;
-    }
-
-    Ok(checkout_dir)
-}
-
-fn get_rev_count(repo: &PathBuf, rev: &str) -> Result<u64, HgError> {
-    let output = Command::new("hg")
-        .args(["log", "-r", &format!("0::{}", rev), "--template", "x"])
-        .current_dir(repo)
-        .env("HGPLAIN", "")
-        .output()?;
-
-    if !output.status.success() {
-        return Ok(0);
-    }
-
-    Ok(output.stdout.len() as u64)
-}
-
-#[derive(Debug)]
-pub enum HgError {
-    IoError(std::io::Error),
-    CommandFailed { operation: String, message: String },
-}
-
-impl std::fmt::Display for HgError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            HgError::IoError(e) => write!(f, "I/O error: {}", e),
-            HgError::CommandFailed { operation, message } => {
-                write!(f, "Mercurial {} failed: {}", operation, message)
-            }
-        }
-    }
-}
-
-impl std::error::Error for HgError {}
-
-impl From<std::io::Error> for HgError {
-    fn from(e: std::io::Error) -> Self {
-        HgError::IoError(e)
-    }
-}

nix-js/src/fetcher/metadata_cache.rs

@@ -1,9 +1,10 @@
 #![allow(dead_code)]
 
+use std::path::PathBuf;
+use std::time::{SystemTime, UNIX_EPOCH};
+
 use rusqlite::{Connection, OptionalExtension, params};
 use serde::{Deserialize, Serialize};
-use std::path::PathBuf;
-use std::time::{SystemTime, UNIX_EPOCH};
 
 #[derive(Debug)]
 pub enum CacheError {

nix-js/src/ir.rs

@@ -1,83 +1,158 @@
-use derive_more::{IsVariant, TryUnwrap, Unwrap};
-use hashbrown::HashMap;
+use std::{
+    hash::{Hash, Hasher},
+    ops::Deref,
+};
+
+use bumpalo::{Bump, boxed::Box, collections::Vec};
+use ghost_cell::{GhostCell, GhostToken};
 use rnix::{TextRange, ast};
 use string_interner::symbol::SymbolU32;
 
-use crate::error::{Result, Source};
-use nix_js_macros::ir;
+pub type HashMap<'ir, K, V> = hashbrown::HashMap<K, V, hashbrown::DefaultHashBuilder, &'ir Bump>;
 
-mod downgrade;
-mod span_utils;
-mod utils;
+#[repr(transparent)]
+#[derive(Clone, Copy)]
+pub struct IrRef<'id, 'ir>(&'ir GhostCell<'id, Ir<'ir, Self>>);
 
-use utils::*;
-
-pub use downgrade::Downgrade;
-pub(crate) use span_utils::*;
-
-pub trait DowngradeContext {
-    fn downgrade(self, expr: rnix::ast::Expr) -> Result<ExprId>;
-
-    fn new_expr(&mut self, expr: Ir) -> ExprId;
-    fn new_arg(&mut self, span: TextRange) -> ExprId;
-    fn maybe_thunk(&mut self, id: ExprId) -> ExprId;
-
-    fn new_sym(&mut self, sym: String) -> SymId;
-    fn get_sym(&self, id: SymId) -> &str;
-    fn lookup(&mut self, sym: SymId, span: TextRange) -> Result<ExprId>;
-
-    fn get_ir(&self, id: ExprId) -> &Ir;
-    fn replace_ir(&mut self, id: ExprId, expr: Ir);
-    fn reserve_slots(&mut self, slots: usize) -> impl Iterator<Item = ExprId> + Clone + use<Self>;
-    fn get_current_source(&self) -> Source;
-
-    fn with_param_scope<F, R>(&mut self, param: SymId, arg: ExprId, f: F) -> R
-    where
-        F: FnOnce(&mut Self) -> R;
-    fn with_let_scope<F, R>(&mut self, bindings: HashMap<SymId, ExprId>, f: F) -> R
-    where
-        F: FnOnce(&mut Self) -> R;
-    fn with_with_scope<F, R>(&mut self, namespace: ExprId, f: F) -> R
-    where
-        F: FnOnce(&mut Self) -> R;
-
-    fn push_thunk_scope(&mut self);
-    fn pop_thunk_scope(&mut self) -> Vec<(ExprId, ExprId)>;
-    fn register_thunk(&mut self, slot: ExprId, inner: ExprId);
+impl<'id, 'ir> IrRef<'id, 'ir> {
+    pub fn new(ir: &'ir GhostCell<'id, Ir<'ir, Self>>) -> Self {
+        Self(ir)
     }
 
-ir! {
-    Ir,
+    pub fn alloc(bump: &'ir Bump, ir: Ir<'ir, Self>) -> Self {
+        Self(bump.alloc(GhostCell::new(ir)))
+    }
 
+    /// Freeze a mutable IR reference into a read-only one, consuming the
+    /// `GhostToken` to prevent any further mutation.
+    ///
+    /// # Safety
+    /// The transmute is sound because:
+    /// - `GhostCell<'id, T>` is `#[repr(transparent)]` over `T`
+    /// - `IrRef<'id, 'ir>` is `#[repr(transparent)]` over
+    ///   `&'ir GhostCell<'id, Ir<'ir, Self>>`
+    /// - `RawIrRef<'ir>` is `#[repr(transparent)]` over `&'ir Ir<'ir, Self>`
+    /// - `Ir<'ir, Ref>` is `#[repr(C)]` and both ref types are pointer-sized
+    ///
+    /// Consuming the `GhostToken` guarantees no `borrow_mut` calls can occur
+    /// afterwards, so the shared `&Ir` references from `RawIrRef::Deref` can
+    /// never alias with mutable references.
+    pub fn freeze(self, _token: GhostToken<'id>) -> RawIrRef<'ir> {
+        unsafe { std::mem::transmute(self) }
+    }
+}
+
+impl<'id, 'ir> Deref for IrRef<'id, 'ir> {
+    type Target = GhostCell<'id, Ir<'ir, IrRef<'id, 'ir>>>;
+    fn deref(&self) -> &Self::Target {
+        self.0
+    }
+}
+
+#[repr(transparent)]
+#[derive(Clone, Copy)]
+pub struct RawIrRef<'ir>(&'ir Ir<'ir, Self>);
+
+impl<'ir> Deref for RawIrRef<'ir> {
+    type Target = Ir<'ir, RawIrRef<'ir>>;
+    fn deref(&self) -> &Self::Target {
+        self.0
+    }
+}
+
+#[repr(C)]
+pub enum Ir<'ir, Ref> {
     Int(i64),
     Float(f64),
     Bool(bool),
     Null,
-    Str { pub val: String },
-    AttrSet { pub stcs: HashMap<SymId, (ExprId, rnix::TextRange)>, pub dyns: Vec<(ExprId, ExprId, rnix::TextRange)> },
-    List { pub items: Vec<ExprId> },
+    Str(Box<'ir, String>),
+    AttrSet {
+        stcs: HashMap<'ir, SymId, (Ref, TextRange)>,
+        dyns: Vec<'ir, (Ref, Ref, TextRange)>,
+    },
+    List {
+        items: Vec<'ir, Ref>,
+    },
+    Path(Ref),
+    ConcatStrings {
+        parts: Vec<'ir, Ref>,
+        force_string: bool,
+    },
 
-    HasAttr { pub lhs: ExprId, pub rhs: Vec<Attr> },
-    BinOp { pub lhs: ExprId, pub rhs: ExprId, pub kind: BinOpKind },
-    UnOp { pub rhs: ExprId, pub kind: UnOpKind },
-    Select { pub expr: ExprId, pub attrpath: Vec<Attr>, pub default: Option<ExprId> },
-    If { pub cond: ExprId, pub consq: ExprId, pub alter: ExprId },
-    Call { pub func: ExprId, pub arg: ExprId },
-    Assert { pub assertion: ExprId, pub expr: ExprId, pub assertion_raw: String },
-    ConcatStrings { pub parts: Vec<ExprId> },
-    Path { pub expr: ExprId },
-    Func { pub body: ExprId, pub param: Option<Param>, pub arg: ExprId, pub thunks: Vec<(ExprId, ExprId)> },
-    TopLevel { pub body: ExprId, pub thunks: Vec<(ExprId, ExprId)> },
+    // OPs
+    UnOp {
+        rhs: Ref,
+        kind: UnOpKind,
+    },
+    BinOp {
+        lhs: Ref,
+        rhs: Ref,
+        kind: BinOpKind,
+    },
+    HasAttr {
+        lhs: Ref,
+        rhs: Vec<'ir, Attr<Ref>>,
+    },
+    Select {
+        expr: Ref,
+        attrpath: Vec<'ir, Attr<Ref>>,
+        default: Option<Ref>,
+        span: TextRange,
+    },
+
+    // Conditionals
+    If {
+        cond: Ref,
+        consq: Ref,
+        alter: Ref,
+    },
+    Assert {
+        assertion: Ref,
+        expr: Ref,
+        assertion_raw: String,
+        span: TextRange,
+    },
+
+    With {
+        namespace: Ref,
+        body: Ref,
+        thunks: Vec<'ir, (ThunkId, Ref)>,
+    },
+    WithLookup(SymId),
+
+    // Function related
+    Func {
+        body: Ref,
+        param: Option<Param<'ir>>,
+        arg: ArgId,
+        thunks: Vec<'ir, (ThunkId, Ref)>,
+    },
     Arg(ArgId),
-    Thunk(ExprId),
+    Call {
+        func: Ref,
+        arg: Ref,
+        span: TextRange,
+    },
+
+    // Builtins
     Builtins,
     Builtin(SymId),
-    CurPos,
+
+    // Misc
+    TopLevel {
+        body: Ref,
+        thunks: Vec<'ir, (ThunkId, Ref)>,
+    },
+    Thunk(ThunkId),
+    CurPos(TextRange),
+    ReplBinding(SymId),
+    ScopedImportBinding(SymId),
 }
 
 #[repr(transparent)]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
-pub struct ExprId(pub usize);
+pub struct ThunkId(pub usize);
 
 pub type SymId = SymbolU32;
 
@@ -87,18 +162,18 @@ pub struct ArgId(pub usize);
 
 /// Represents a key in an attribute path.
 #[allow(unused)]
-#[derive(Debug, TryUnwrap)]
-pub enum Attr {
+#[derive(Debug)]
+pub enum Attr<Ref> {
     /// A dynamic attribute key, which is an expression that must evaluate to a string.
     /// Example: `attrs.${key}`
-    Dynamic(ExprId, TextRange),
+    Dynamic(Ref, TextRange),
     /// A static attribute key.
     /// Example: `attrs.key`
     Str(SymId, TextRange),
 }
 
 /// The kinds of binary operations supported in Nix.
-#[derive(Clone, Debug)]
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
 pub enum BinOpKind {
     // Arithmetic
     Add,
@@ -155,7 +230,7 @@ impl From<ast::BinOpKind> for BinOpKind {
 }
 
 /// The kinds of unary operations.
-#[derive(Clone, Debug)]
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
 pub enum UnOpKind {
     Neg, // Negation (`-`)
     Not, // Logical not (`!`)
@@ -172,8 +247,437 @@ impl From<ast::UnaryOpKind> for UnOpKind {
 
 /// Describes the parameters of a function.
 #[derive(Debug)]
-pub struct Param {
-    pub required: Vec<SymId>,
-    pub optional: Vec<SymId>,
+pub struct Param<'ir> {
+    pub required: Vec<'ir, (SymId, TextRange)>,
+    pub optional: Vec<'ir, (SymId, TextRange)>,
     pub ellipsis: bool,
 }
+
+#[derive(Clone, Copy)]
+pub(crate) struct IrKey<'id, 'ir, 'a>(pub IrRef<'id, 'ir>, pub &'a GhostToken<'id>);
+
+impl std::hash::Hash for IrKey<'_, '_, '_> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        ir_content_hash(self.0, self.1, state);
+    }
+}
+
+impl PartialEq for IrKey<'_, '_, '_> {
+    fn eq(&self, other: &Self) -> bool {
+        ir_content_eq(self.0, other.0, self.1)
+    }
+}
+
+impl Eq for IrKey<'_, '_, '_> {}
+
+fn attr_content_hash<'id>(
+    attr: &Attr<IrRef<'id, '_>>,
+    token: &GhostToken<'id>,
+    state: &mut impl Hasher,
+) {
+    core::mem::discriminant(attr).hash(state);
+    match attr {
+        Attr::Dynamic(expr, _) => ir_content_hash(*expr, token, state),
+        Attr::Str(sym, _) => sym.hash(state),
+    }
+}
+
+fn attr_content_eq<'id, 'ir>(
+    a: &Attr<IrRef<'id, 'ir>>,
+    b: &Attr<IrRef<'id, 'ir>>,
+    token: &GhostToken<'id>,
+) -> bool {
+    match (a, b) {
+        (Attr::Dynamic(ae, _), Attr::Dynamic(be, _)) => ir_content_eq(*ae, *be, token),
+        (Attr::Str(a, _), Attr::Str(b, _)) => a == b,
+        _ => false,
+    }
+}
+
+fn param_content_hash(param: &Param<'_>, state: &mut impl Hasher) {
+    param.required.len().hash(state);
+    for (sym, _) in param.required.iter() {
+        sym.hash(state);
+    }
+    param.optional.len().hash(state);
+    for (sym, _) in param.optional.iter() {
+        sym.hash(state);
+    }
+    param.ellipsis.hash(state);
+}
+
+fn param_content_eq(a: &Param<'_>, b: &Param<'_>) -> bool {
+    a.ellipsis == b.ellipsis
+        && a.required.len() == b.required.len()
+        && a.optional.len() == b.optional.len()
+        && a.required
+            .iter()
+            .zip(b.required.iter())
+            .all(|((a, _), (b, _))| a == b)
+        && a.optional
+            .iter()
+            .zip(b.optional.iter())
+            .all(|((a, _), (b, _))| a == b)
+}
+
+fn thunks_content_hash<'id>(
+    thunks: &[(ThunkId, IrRef<'id, '_>)],
+    token: &GhostToken<'id>,
+    state: &mut impl Hasher,
+) {
+    thunks.len().hash(state);
+    for &(id, ir) in thunks {
+        id.hash(state);
+        ir_content_hash(ir, token, state);
+    }
+}
+
+fn thunks_content_eq<'id, 'ir>(
+    a: &[(ThunkId, IrRef<'id, 'ir>)],
+    b: &[(ThunkId, IrRef<'id, 'ir>)],
+    token: &GhostToken<'id>,
+) -> bool {
+    a.len() == b.len()
+        && a.iter()
+            .zip(b.iter())
+            .all(|(&(ai, ae), &(bi, be))| ai == bi && ir_content_eq(ae, be, token))
+}
+
+fn ir_content_hash<'id>(ir: IrRef<'id, '_>, token: &GhostToken<'id>, state: &mut impl Hasher) {
+    let ir = ir.borrow(token);
+    core::mem::discriminant(ir).hash(state);
+    match ir {
+        Ir::Int(x) => x.hash(state),
+        Ir::Float(x) => x.to_bits().hash(state),
+        Ir::Bool(x) => x.hash(state),
+        Ir::Null => {}
+        Ir::Str(x) => x.hash(state),
+        Ir::AttrSet { stcs, dyns } => {
+            stcs.len().hash(state);
+            let mut combined: u64 = 0;
+            for (&key, &(val, _)) in stcs.iter() {
+                let mut h = std::hash::DefaultHasher::new();
+                key.hash(&mut h);
+                ir_content_hash(val, token, &mut h);
+                combined = combined.wrapping_add(h.finish());
+            }
+            combined.hash(state);
+            dyns.len().hash(state);
+            for &(k, v, _) in dyns.iter() {
+                ir_content_hash(k, token, state);
+                ir_content_hash(v, token, state);
+            }
+        }
+        Ir::List { items } => {
+            items.len().hash(state);
+            for &item in items.iter() {
+                ir_content_hash(item, token, state);
+            }
+        }
+        Ir::HasAttr { lhs, rhs } => {
+            ir_content_hash(*lhs, token, state);
+            rhs.len().hash(state);
+            for attr in rhs.iter() {
+                attr_content_hash(attr, token, state);
+            }
+        }
+        &Ir::BinOp { lhs, rhs, kind } => {
+            ir_content_hash(lhs, token, state);
+            ir_content_hash(rhs, token, state);
+            kind.hash(state);
+        }
+        &Ir::UnOp { rhs, kind } => {
+            ir_content_hash(rhs, token, state);
+            kind.hash(state);
+        }
+        Ir::Select {
+            expr,
+            attrpath,
+            default,
+            ..
+        } => {
+            ir_content_hash(*expr, token, state);
+            attrpath.len().hash(state);
+            for attr in attrpath.iter() {
+                attr_content_hash(attr, token, state);
+            }
+            default.is_some().hash(state);
+            if let Some(d) = default {
+                ir_content_hash(*d, token, state);
+            }
+        }
+        &Ir::If { cond, consq, alter } => {
+            ir_content_hash(cond, token, state);
+            ir_content_hash(consq, token, state);
+            ir_content_hash(alter, token, state);
+        }
+        &Ir::Call { func, arg, .. } => {
+            ir_content_hash(func, token, state);
+            ir_content_hash(arg, token, state);
+        }
+        Ir::Assert {
+            assertion,
+            expr,
+            assertion_raw,
+            ..
+        } => {
+            ir_content_hash(*assertion, token, state);
+            ir_content_hash(*expr, token, state);
+            assertion_raw.hash(state);
+        }
+        Ir::ConcatStrings {
+            force_string,
+            parts,
+        } => {
+            force_string.hash(state);
+            parts.len().hash(state);
+            for &part in parts.iter() {
+                ir_content_hash(part, token, state);
+            }
+        }
+        &Ir::Path(expr) => ir_content_hash(expr, token, state),
+        Ir::Func {
+            body,
+            arg,
+            param,
+            thunks,
+        } => {
+            ir_content_hash(*body, token, state);
+            arg.hash(state);
+            param.is_some().hash(state);
+            if let Some(p) = param {
+                param_content_hash(p, state);
+            }
+            thunks_content_hash(thunks, token, state);
+        }
+        Ir::TopLevel { body, thunks } => {
+            ir_content_hash(*body, token, state);
+            thunks_content_hash(thunks, token, state);
+        }
+        Ir::Arg(x) => x.hash(state),
+        Ir::Thunk(x) => x.hash(state),
+        Ir::Builtins => {}
+        Ir::Builtin(x) => x.hash(state),
+        Ir::CurPos(x) => x.hash(state),
+        Ir::ReplBinding(x) => x.hash(state),
+        Ir::ScopedImportBinding(x) => x.hash(state),
+        &Ir::With {
+            namespace,
+            body,
+            ref thunks,
+        } => {
+            ir_content_hash(namespace, token, state);
+            ir_content_hash(body, token, state);
+            thunks_content_hash(thunks, token, state);
+        }
+        Ir::WithLookup(x) => x.hash(state),
+    }
+}
+
+pub(crate) fn ir_content_eq<'id, 'ir>(
+    a: IrRef<'id, 'ir>,
+    b: IrRef<'id, 'ir>,
+    token: &GhostToken<'id>,
+) -> bool {
+    std::ptr::eq(a.0, b.0)
+        || match (a.borrow(token), b.borrow(token)) {
+            (Ir::Int(a), Ir::Int(b)) => a == b,
+            (Ir::Float(a), Ir::Float(b)) => a.to_bits() == b.to_bits(),
+            (Ir::Bool(a), Ir::Bool(b)) => a == b,
+            (Ir::Null, Ir::Null) => true,
+            (Ir::Str(a), Ir::Str(b)) => **a == **b,
+            (
+                Ir::AttrSet {
+                    stcs: a_stcs,
+                    dyns: a_dyns,
+                },
+                Ir::AttrSet {
+                    stcs: b_stcs,
+                    dyns: b_dyns,
+                },
+            ) => {
+                a_stcs.len() == b_stcs.len()
+                    && a_dyns.len() == b_dyns.len()
+                    && a_stcs.iter().all(|(&k, &(av, _))| {
+                        b_stcs
+                            .get(&k)
+                            .is_some_and(|&(bv, _)| ir_content_eq(av, bv, token))
+                    })
+                    && a_dyns
+                        .iter()
+                        .zip(b_dyns.iter())
+                        .all(|(&(ak, av, _), &(bk, bv, _))| {
+                            ir_content_eq(ak, bk, token) && ir_content_eq(av, bv, token)
+                        })
+            }
+            (Ir::List { items: a }, Ir::List { items: b }) => {
+                a.len() == b.len()
+                    && a.iter()
+                        .zip(b.iter())
+                        .all(|(&a, &b)| ir_content_eq(a, b, token))
+            }
+            (Ir::HasAttr { lhs: al, rhs: ar }, Ir::HasAttr { lhs: bl, rhs: br }) => {
+                ir_content_eq(*al, *bl, token)
+                    && ar.len() == br.len()
+                    && ar
+                        .iter()
+                        .zip(br.iter())
+                        .all(|(a, b)| attr_content_eq(a, b, token))
+            }
+            (
+                &Ir::BinOp {
+                    lhs: al,
+                    rhs: ar,
+                    kind: ak,
+                },
+                &Ir::BinOp {
+                    lhs: bl,
+                    rhs: br,
+                    kind: bk,
+                },
+            ) => ak == bk && ir_content_eq(al, bl, token) && ir_content_eq(ar, br, token),
+            (&Ir::UnOp { rhs: ar, kind: ak }, &Ir::UnOp { rhs: br, kind: bk }) => {
+                ak == bk && ir_content_eq(ar, br, token)
+            }
+            (
+                Ir::Select {
+                    expr: ae,
+                    attrpath: aa,
+                    default: ad,
+                    ..
+                },
+                Ir::Select {
+                    expr: be,
+                    attrpath: ba,
+                    default: bd,
+                    ..
+                },
+            ) => {
+                ir_content_eq(*ae, *be, token)
+                    && aa.len() == ba.len()
+                    && aa
+                        .iter()
+                        .zip(ba.iter())
+                        .all(|(a, b)| attr_content_eq(a, b, token))
+                    && match (ad, bd) {
+                        (Some(a), Some(b)) => ir_content_eq(*a, *b, token),
+                        (None, None) => true,
+                        _ => false,
+                    }
+            }
+            (
+                &Ir::If {
+                    cond: ac,
+                    consq: acs,
+                    alter: aa,
+                },
+                &Ir::If {
+                    cond: bc,
+                    consq: bcs,
+                    alter: ba,
+                },
+            ) => {
+                ir_content_eq(ac, bc, token)
+                    && ir_content_eq(acs, bcs, token)
+                    && ir_content_eq(aa, ba, token)
+            }
+            (
+                &Ir::Call {
+                    func: af, arg: aa, ..
+                },
+                &Ir::Call {
+                    func: bf, arg: ba, ..
+                },
+            ) => ir_content_eq(af, bf, token) && ir_content_eq(aa, ba, token),
+            (
+                Ir::Assert {
+                    assertion: aa,
+                    expr: ae,
+                    assertion_raw: ar,
+                    ..
+                },
+                Ir::Assert {
+                    assertion: ba,
+                    expr: be,
+                    assertion_raw: br,
+                    ..
+                },
+            ) => ar == br && ir_content_eq(*aa, *ba, token) && ir_content_eq(*ae, *be, token),
+            (
+                Ir::ConcatStrings {
+                    force_string: af,
+                    parts: ap,
+                },
+                Ir::ConcatStrings {
+                    force_string: bf,
+                    parts: bp,
+                },
+            ) => {
+                af == bf
+                    && ap.len() == bp.len()
+                    && ap
+                        .iter()
+                        .zip(bp.iter())
+                        .all(|(&a, &b)| ir_content_eq(a, b, token))
+            }
+            (&Ir::Path(a), &Ir::Path(b)) => ir_content_eq(a, b, token),
+            (
+                Ir::Func {
+                    body: ab,
+                    arg: aa,
+                    param: ap,
+                    thunks: at,
+                },
+                Ir::Func {
+                    body: bb,
+                    arg: ba,
+                    param: bp,
+                    thunks: bt,
+                },
+            ) => {
+                ir_content_eq(*ab, *bb, token)
+                    && aa == ba
+                    && match (ap, bp) {
+                        (Some(a), Some(b)) => param_content_eq(a, b),
+                        (None, None) => true,
+                        _ => false,
+                    }
+                    && thunks_content_eq(at, bt, token)
+            }
+            (
+                Ir::TopLevel {
+                    body: ab,
+                    thunks: at,
+                },
+                Ir::TopLevel {
+                    body: bb,
+                    thunks: bt,
+                },
+            ) => ir_content_eq(*ab, *bb, token) && thunks_content_eq(at, bt, token),
+            (Ir::Arg(a), Ir::Arg(b)) => a == b,
+            (Ir::Thunk(a), Ir::Thunk(b)) => a == b,
+            (Ir::Builtins, Ir::Builtins) => true,
+            (Ir::Builtin(a), Ir::Builtin(b)) => a == b,
+            (Ir::CurPos(a), Ir::CurPos(b)) => a == b,
+            (Ir::ReplBinding(a), Ir::ReplBinding(b)) => a == b,
+            (Ir::ScopedImportBinding(a), Ir::ScopedImportBinding(b)) => a == b,
+            (
+                Ir::With {
+                    namespace: a_ns,
+                    body: a_body,
+                    thunks: a_thunks,
+                },
+                Ir::With {
+                    namespace: b_ns,
+                    body: b_body,
+                    thunks: b_thunks,
+                },
+            ) => {
+                ir_content_eq(*a_ns, *b_ns, token)
+                    && ir_content_eq(*a_body, *b_body, token)
+                    && thunks_content_eq(a_thunks, b_thunks, token)
+            }
+            (Ir::WithLookup(a), Ir::WithLookup(b)) => a == b,
+            _ => false,
+        }
+}

nix-js/src/ir/downgrade.rs

@@ -1,439 +0,0 @@
-// Assume no parse error
-#![allow(clippy::unwrap_used)]
-
-use rnix::ast::{self, AstToken, Expr, HasEntry};
-use rowan::ast::AstNode;
-
-use super::*;
-use crate::error::{Error, Result};
-
-pub trait Downgrade<Ctx: DowngradeContext> {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId>;
-}
-
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for Expr {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        use Expr::*;
-        match self {
-            Apply(apply) => apply.downgrade(ctx),
-            Assert(assert) => assert.downgrade(ctx),
-            Error(error) => {
-                let span = error.syntax().text_range();
-                Err(self::Error::downgrade_error(
-                    error.to_string(),
-                    ctx.get_current_source(),
-                    span,
-                ))
-            }
-            IfElse(ifelse) => ifelse.downgrade(ctx),
-            Select(select) => select.downgrade(ctx),
-            Str(str) => str.downgrade(ctx),
-            Path(path) => path.downgrade(ctx),
-            Literal(lit) => lit.downgrade(ctx),
-            Lambda(lambda) => lambda.downgrade(ctx),
-            LegacyLet(let_) => let_.downgrade(ctx),
-            LetIn(letin) => letin.downgrade(ctx),
-            List(list) => list.downgrade(ctx),
-            BinOp(op) => op.downgrade(ctx),
-            AttrSet(attrs) => attrs.downgrade(ctx),
-            UnaryOp(op) => op.downgrade(ctx),
-            Ident(ident) => ident.downgrade(ctx),
-            With(with) => with.downgrade(ctx),
-            HasAttr(has) => has.downgrade(ctx),
-            Paren(paren) => paren.expr().unwrap().downgrade(ctx),
-            Root(root) => root.expr().unwrap().downgrade(ctx),
-        }
-    }
-}
-
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Assert {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let assertion = self.condition().unwrap();
-        let assertion_raw = assertion.to_string();
-        let assertion = assertion.downgrade(ctx)?;
-        let expr = self.body().unwrap().downgrade(ctx)?;
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(
-            Assert {
-                assertion,
-                expr,
-                assertion_raw,
-                span,
-            }
-            .to_ir(),
-        ))
-    }
-}
-
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::IfElse {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let cond = self.condition().unwrap().downgrade(ctx)?;
-        let consq = self.body().unwrap().downgrade(ctx)?;
-        let alter = self.else_body().unwrap().downgrade(ctx)?;
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(
-            If {
-                cond,
-                consq,
-                alter,
-                span,
-            }
-            .to_ir(),
-        ))
-    }
-}
-
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Path {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let span = self.syntax().text_range();
-        let parts = self
-            .parts()
-            .map(|part| match part {
-                ast::InterpolPart::Literal(lit) => Ok(ctx.new_expr(
-                    Str {
-                        val: lit.to_string(),
-                        span: lit.syntax().text_range(),
-                    }
-                    .to_ir(),
-                )),
-                ast::InterpolPart::Interpolation(interpol) => {
-                    interpol.expr().unwrap().downgrade(ctx)
-                }
-            })
-            .collect::<Result<Vec<_>>>()?;
-
-        let expr = if parts.len() == 1 {
-            let part = parts.into_iter().next().unwrap();
-            if let &Ir::Str(Str { ref val, span }) = ctx.get_ir(part)
-                && let Some(path) = val.strip_prefix("<").map(|path| &path[..path.len() - 1])
-            {
-                ctx.replace_ir(
-                    part,
-                    Str {
-                        val: path.to_string(),
-                        span,
-                    }
-                    .to_ir(),
-                );
-                let sym = ctx.new_sym("findFile".into());
-                let find_file = ctx.new_expr(Builtin { inner: sym, span }.to_ir());
-                let sym = ctx.new_sym("nixPath".into());
-                let nix_path = ctx.new_expr(Builtin { inner: sym, span }.to_ir());
-                let call = ctx.new_expr(
-                    Call {
-                        func: find_file,
-                        arg: nix_path,
-                        span,
-                    }
-                    .to_ir(),
-                );
-                return Ok(ctx.new_expr(
-                    Call {
-                        func: call,
-                        arg: part,
-                        span,
-                    }
-                    .to_ir(),
-                ));
-            } else {
-                part
-            }
-        } else {
-            ctx.new_expr(ConcatStrings { parts, span }.to_ir())
-        };
-        Ok(ctx.new_expr(Path { expr, span }.to_ir()))
-    }
-}
-
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Str {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let span = self.syntax().text_range();
-        let normalized = self.normalized_parts();
-        let is_single_literal = normalized.len() == 1
-            && matches!(normalized.first(), Some(ast::InterpolPart::Literal(_)));
-
-        let parts = normalized
-            .into_iter()
-            .map(|part| match part {
-                ast::InterpolPart::Literal(lit) => Ok(ctx.new_expr(Str { val: lit, span }.to_ir())),
-                ast::InterpolPart::Interpolation(interpol) => {
-                    let inner = interpol.expr().unwrap().downgrade(ctx)?;
-                    Ok(ctx.maybe_thunk(inner))
-                }
-            })
-            .collect::<Result<Vec<_>>>()?;
-
-        Ok(if is_single_literal {
-            parts.into_iter().next().unwrap()
-        } else {
-            ctx.new_expr(ConcatStrings { parts, span }.to_ir())
-        })
-    }
-}
-
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Literal {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(match self.kind() {
-            ast::LiteralKind::Integer(int) => Int {
-                inner: int.value().unwrap(),
-                span,
-            }
-            .to_ir(),
-            ast::LiteralKind::Float(float) => Float {
-                inner: float.value().unwrap(),
-                span,
-            }
-            .to_ir(),
-            ast::LiteralKind::Uri(uri) => Str {
-                val: uri.to_string(),
-                span,
-            }
-            .to_ir(),
-        }))
-    }
-}
-
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Ident {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let text = self.ident_token().unwrap().to_string();
-        let span = self.syntax().text_range();
-
-        if text == "__curPos" {
-            return Ok(ctx.new_expr(CurPos { span }.to_ir()));
-        }
-
-        let sym = ctx.new_sym(text);
-        ctx.lookup(sym, span)
-    }
-}
-
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::AttrSet {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let rec = self.rec_token().is_some();
-        let span = self.syntax().text_range();
-
-        if !rec {
-            let attrs = downgrade_attrs(self, ctx)?;
-            return Ok(ctx.new_expr(attrs.to_ir()));
-        }
-
-        // rec { a = 1; b = a; } => let a = 1; b = a; in { inherit a b; }
-        let entries: Vec<_> = self.entries().collect();
-        downgrade_rec_bindings(entries, ctx, span)
-    }
-}
-
-/// Downgrades a list.
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::List {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let items = self
-            .items()
-            .map(|item| {
-                let id = item.downgrade(ctx)?;
-                Ok(ctx.maybe_thunk(id))
-            })
-            .collect::<Result<_>>()?;
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(List { items, span }.to_ir()))
-    }
-}
-
-/// Downgrades a binary operation.
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::BinOp {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let lhs = self.lhs().unwrap().downgrade(ctx)?;
-        let rhs = self.rhs().unwrap().downgrade(ctx)?;
-        let kind = self.operator().unwrap().into();
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(
-            BinOp {
-                lhs,
-                rhs,
-                kind,
-                span,
-            }
-            .to_ir(),
-        ))
-    }
-}
-
-/// Downgrades a "has attribute" (`?`) expression.
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::HasAttr {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let lhs = self.expr().unwrap().downgrade(ctx)?;
-        let rhs = downgrade_attrpath(self.attrpath().unwrap(), ctx)?;
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(HasAttr { lhs, rhs, span }.to_ir()))
-    }
-}
-
-/// Downgrades a unary operation.
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::UnaryOp {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let rhs = self.expr().unwrap().downgrade(ctx)?;
-        let kind = self.operator().unwrap().into();
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(UnOp { rhs, kind, span }.to_ir()))
-    }
-}
-
-/// Downgrades an attribute selection (`.`).
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Select {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let expr = self.expr().unwrap().downgrade(ctx)?;
-        let attrpath = downgrade_attrpath(self.attrpath().unwrap(), ctx)?;
-        let default = if let Some(default) = self.default_expr() {
-            let default_expr = default.downgrade(ctx)?;
-            Some(ctx.maybe_thunk(default_expr))
-        } else {
-            None
-        };
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(
-            Select {
-                expr,
-                attrpath,
-                default,
-                span,
-            }
-            .to_ir(),
-        ))
-    }
-}
-
-/// Downgrades a `legacy let`, which is essentially a recursive attribute set.
-/// The body of the `let` is accessed via `let.body`.
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::LegacyLet {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let span = self.syntax().text_range();
-        let entries: Vec<_> = self.entries().collect();
-        let attrset_expr = downgrade_let_bindings(entries, ctx, span, |ctx, binding_keys| {
-            // Create plain attrset as body with inherit
-            let mut attrs = AttrSet {
-                stcs: HashMap::new(),
-                dyns: Vec::new(),
-                span,
-            };
-
-            for sym in binding_keys {
-                let expr = ctx.lookup(*sym, synthetic_span())?;
-                attrs.stcs.insert(*sym, (expr, synthetic_span()));
-            }
-
-            Ok(ctx.new_expr(attrs.to_ir()))
-        })?;
-
-        let body_sym = ctx.new_sym("body".to_string());
-        let select = Select {
-            expr: attrset_expr,
-            attrpath: vec![Attr::Str(body_sym, synthetic_span())],
-            default: None,
-            span,
-        };
-
-        Ok(ctx.new_expr(select.to_ir()))
-    }
-}
-
-/// Downgrades a `let ... in ...` expression.
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::LetIn {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let entries: Vec<_> = self.entries().collect();
-        let body_expr = self.body().unwrap();
-        let span = self.syntax().text_range();
-
-        downgrade_let_bindings(entries, ctx, span, |ctx, _binding_keys| {
-            body_expr.downgrade(ctx)
-        })
-    }
-}
-
-/// Downgrades a `with` expression.
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::With {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        // with namespace; expr
-        let namespace = self.namespace().unwrap().downgrade(ctx)?;
-
-        // Downgrade body in With scope
-        let expr = ctx.with_with_scope(namespace, |ctx| self.body().unwrap().downgrade(ctx))?;
-
-        Ok(expr)
-    }
-}
-
-/// Downgrades a lambda (function) expression.
-/// This involves desugaring pattern-matching arguments into `let` bindings.
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Lambda {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let raw_param = self.param().unwrap();
-        let arg = ctx.new_arg(raw_param.syntax().text_range());
-
-        ctx.push_thunk_scope();
-
-        let param;
-        let body;
-
-        match raw_param {
-            ast::Param::IdentParam(id) => {
-                // Simple case: `x: body`
-                let param_sym = ctx.new_sym(id.to_string());
-                param = None;
-
-                // Downgrade body in Param scope
-                body = ctx
-                    .with_param_scope(param_sym, arg, |ctx| self.body().unwrap().downgrade(ctx))?;
-            }
-            ast::Param::Pattern(pattern) => {
-                let alias = pattern
-                    .pat_bind()
-                    .map(|alias| ctx.new_sym(alias.ident().unwrap().to_string()));
-
-                let ellipsis = pattern.ellipsis_token().is_some();
-                let pat_entries = pattern.pat_entries();
-
-                let PatternBindings {
-                    body: inner_body,
-                    required,
-                    optional,
-                } = downgrade_pattern_bindings(pat_entries, alias, arg, ctx, |ctx, _| {
-                    self.body().unwrap().downgrade(ctx)
-                })?;
-
-                param = Some(Param {
-                    required,
-                    optional,
-                    ellipsis,
-                });
-
-                body = inner_body;
-            }
-        }
-
-        let thunks = ctx.pop_thunk_scope();
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(
-            Func {
-                body,
-                param,
-                arg,
-                thunks,
-                span,
-            }
-            .to_ir(),
-        ))
-    }
-}
-
-/// Downgrades a function application.
-/// In Nix, function application is left-associative, so `f a b` should be parsed as `((f a) b)`.
-/// Each Apply node represents a single function call with one argument.
-impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Apply {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<ExprId> {
-        let func = self.lambda().unwrap().downgrade(ctx)?;
-        let arg = self.argument().unwrap().downgrade(ctx)?;
-        let arg = ctx.maybe_thunk(arg);
-        let span = self.syntax().text_range();
-        Ok(ctx.new_expr(Call { func, arg, span }.to_ir()))
-    }
-}

nix-js/src/ir/span_utils.rs

@@ -1,18 +0,0 @@
-#![allow(unused)]
-
-use rnix::TextRange;
-
-pub fn merge_spans(spans: impl IntoIterator<Item = TextRange>) -> TextRange {
-    let mut spans = spans.into_iter();
-    let first = spans.next().unwrap_or_else(synthetic_span);
-
-    spans.fold(first, |acc, span| {
-        let start = acc.start().min(span.start());
-        let end = acc.end().max(span.end());
-        TextRange::new(start, end)
-    })
-}
-
-pub fn synthetic_span() -> TextRange {
-    TextRange::new(0.into(), 0.into())
-}

nix-js/src/ir/utils.rs

@@ -1,844 +0,0 @@
-// Assume no parse error
-#![allow(clippy::unwrap_used)]
-
-use hashbrown::hash_map::Entry;
-use hashbrown::{HashMap, HashSet};
-use itertools::Itertools as _;
-use rnix::TextRange;
-use rnix::ast::{self, HasEntry};
-use rowan::ast::AstNode;
-
-use crate::error::{Error, Result};
-use crate::ir::{Attr, AttrSet, ConcatStrings, ExprId, Select, Str, SymId};
-use crate::value::format_symbol;
-
-use super::*;
-
-enum PendingValue {
-    Expr(ast::Expr),
-    InheritFrom(ast::Expr, SymId, TextRange),
-    InheritScope(SymId, TextRange),
-    Set(PendingAttrSet),
-    ExtendedRecAttrSet {
-        base: ast::AttrSet,
-        extensions: Vec<ast::Entry>,
-        span: TextRange,
-    },
-}
-
-struct PendingAttrSet {
-    stcs: HashMap<SymId, (PendingValue, TextRange)>,
-    dyns: Vec<(ast::Attr, PendingValue, TextRange)>,
-    span: TextRange,
-}
-
-impl PendingAttrSet {
-    fn new(span: TextRange) -> Self {
-        Self {
-            stcs: HashMap::new(),
-            dyns: Vec::new(),
-            span,
-        }
-    }
-
-    fn insert(
-        &mut self,
-        path: &[ast::Attr],
-        value: ast::Expr,
-        ctx: &mut impl DowngradeContext,
-    ) -> Result<()> {
-        let first = path.first().expect("empty attrpath passed. this is a bug");
-        let rest = &path[1..];
-        let span = first.syntax().text_range();
-
-        match first {
-            ast::Attr::Ident(ident) => {
-                let sym = ctx.new_sym(ident.to_string());
-                self.insert_static(sym, span, rest, value, ctx)
-            }
-            ast::Attr::Str(string) => {
-                let parts = string.normalized_parts();
-                if parts.len() == 1
-                    && let ast::InterpolPart::Literal(lit) = parts.into_iter().next().unwrap()
-                {
-                    let sym = ctx.new_sym(lit);
-                    return self.insert_static(sym, span, rest, value, ctx);
-                }
-                self.insert_dynamic(first.clone(), span, rest, value)
-            }
-            ast::Attr::Dynamic(_) => self.insert_dynamic(first.clone(), span, rest, value),
-        }
-    }
-
-    fn insert_static(
-        &mut self,
-        sym: SymId,
-        span: TextRange,
-        path: &[ast::Attr],
-        value: ast::Expr,
-        ctx: &mut impl DowngradeContext,
-    ) -> Result<()> {
-        if !path.is_empty() {
-            match self.stcs.entry(sym) {
-                Entry::Occupied(mut entry) => {
-                    let (existing, existing_span) = entry.get_mut();
-
-                    if let PendingValue::Expr(ast::Expr::AttrSet(attrset)) = existing
-                        && attrset.rec_token().is_some()
-                    {
-                        let base = attrset.clone();
-                        let base_span = attrset.syntax().text_range();
-                        let ext_entry = make_attrpath_value_entry(path.to_vec(), value);
-                        *existing = PendingValue::ExtendedRecAttrSet {
-                            base,
-                            extensions: vec![ext_entry],
-                            span: base_span,
-                        };
-                        return Ok(());
-                    }
-
-                    if let PendingValue::ExtendedRecAttrSet { extensions, .. } = existing {
-                        let ext_entry = make_attrpath_value_entry(path.to_vec(), value);
-                        extensions.push(ext_entry);
-                        return Ok(());
-                    }
-
-                    let nested = Self::ensure_pending_set(existing, ctx, *existing_span)?;
-                    nested.insert(path, value, ctx)
-                }
-                Entry::Vacant(entry) => {
-                    let mut nested = PendingAttrSet::new(span);
-                    nested.insert(path, value, ctx)?;
-                    entry.insert((PendingValue::Set(nested), span));
-                    Ok(())
-                }
-            }
-        } else {
-            match self.stcs.entry(sym) {
-                Entry::Occupied(mut entry) => {
-                    let (existing, existing_span) = entry.get_mut();
-                    Self::merge_value(existing, *existing_span, value, span, ctx)
-                }
-                Entry::Vacant(entry) => {
-                    entry.insert((PendingValue::Expr(value), span));
-                    Ok(())
-                }
-            }
-        }
-    }
-
-    fn insert_dynamic(
-        &mut self,
-        attr: ast::Attr,
-        span: TextRange,
-        path: &[ast::Attr],
-        value: ast::Expr,
-    ) -> Result<()> {
-        if !path.is_empty() {
-            let mut nested = PendingAttrSet::new(span);
-            nested.insert_dynamic(
-                path[0].clone(),
-                path[0].syntax().text_range(),
-                &path[1..],
-                value,
-            )?;
-            self.dyns.push((attr, PendingValue::Set(nested), span));
-        } else {
-            self.dyns.push((attr, PendingValue::Expr(value), span));
-        }
-        Ok(())
-    }
-
-    fn ensure_pending_set<'a>(
-        value: &'a mut PendingValue,
-        ctx: &mut impl DowngradeContext,
-        span: TextRange,
-    ) -> Result<&'a mut PendingAttrSet> {
-        match value {
-            PendingValue::Set(set) => Ok(set),
-            PendingValue::Expr(expr) => {
-                if let ast::Expr::AttrSet(attrset) = expr {
-                    let mut nested = PendingAttrSet::new(attrset.syntax().text_range());
-                    nested.collect_entries(attrset.entries(), ctx)?;
-                    *value = PendingValue::Set(nested);
-                    match value {
-                        PendingValue::Set(set) => Ok(set),
-                        _ => unreachable!(),
-                    }
-                } else {
-                    Err(Error::downgrade_error(
-                        "attribute already defined but is not an attribute set".to_string(),
-                        ctx.get_current_source(),
-                        span,
-                    ))
-                }
-            }
-            PendingValue::ExtendedRecAttrSet { .. } => Err(Error::downgrade_error(
-                "cannot add nested attributes to rec attribute set with extensions".to_string(),
-                ctx.get_current_source(),
-                span,
-            )),
-            PendingValue::InheritFrom(..) | PendingValue::InheritScope(..) => {
-                Err(Error::downgrade_error(
-                    "attribute already defined (inherited)".to_string(),
-                    ctx.get_current_source(),
-                    span,
-                ))
-            }
-        }
-    }
-
-    fn merge_value(
-        existing: &mut PendingValue,
-        existing_span: TextRange,
-        new_value: ast::Expr,
-        new_span: TextRange,
-        ctx: &mut impl DowngradeContext,
-    ) -> Result<()> {
-        match existing {
-            PendingValue::Set(existing_set) => {
-                if let ast::Expr::AttrSet(new_attrset) = new_value {
-                    existing_set.collect_entries(new_attrset.entries(), ctx)
-                } else {
-                    Err(Error::downgrade_error(
-                        "attribute already defined as attribute set".to_string(),
-                        ctx.get_current_source(),
-                        new_span,
-                    ))
-                }
-            }
-            PendingValue::Expr(existing_expr) => {
-                if let ast::Expr::AttrSet(existing_attrset) = existing_expr {
-                    if let ast::Expr::AttrSet(new_attrset) = new_value {
-                        let is_rec = existing_attrset.rec_token().is_some();
-                        if is_rec {
-                            let base = existing_attrset.clone();
-                            let extensions: Vec<_> = new_attrset.entries().collect();
-                            *existing = PendingValue::ExtendedRecAttrSet {
-                                base,
-                                extensions,
-                                span: existing_attrset.syntax().text_range(),
-                            };
-                            Ok(())
-                        } else {
-                            let mut merged =
-                                PendingAttrSet::new(existing_attrset.syntax().text_range());
-                            merged.collect_entries(existing_attrset.entries(), ctx)?;
-                            merged.collect_entries(new_attrset.entries(), ctx)?;
-                            *existing = PendingValue::Set(merged);
-                            Ok(())
-                        }
-                    } else {
-                        Err(Error::downgrade_error(
-                            "attribute already defined as attribute set".to_string(),
-                            ctx.get_current_source(),
-                            new_span,
-                        ))
-                    }
-                } else {
-                    Err(Error::downgrade_error(
-                        "attribute already defined".to_string(),
-                        ctx.get_current_source(),
-                        existing_span,
-                    ))
-                }
-            }
-            PendingValue::ExtendedRecAttrSet { extensions, .. } => {
-                if let ast::Expr::AttrSet(new_attrset) = new_value {
-                    extensions.extend(new_attrset.entries());
-                    Ok(())
-                } else {
-                    Err(Error::downgrade_error(
-                        "attribute already defined as attribute set".to_string(),
-                        ctx.get_current_source(),
-                        new_span,
-                    ))
-                }
-            }
-            PendingValue::InheritFrom(..) | PendingValue::InheritScope(..) => {
-                Err(Error::downgrade_error(
-                    "attribute already defined (inherited)".to_string(),
-                    ctx.get_current_source(),
-                    existing_span,
-                ))
-            }
-        }
-    }
-
-    fn collect_entries(
-        &mut self,
-        entries: impl Iterator<Item = ast::Entry>,
-        ctx: &mut impl DowngradeContext,
-    ) -> Result<()> {
-        for entry in entries {
-            match entry {
-                ast::Entry::Inherit(inherit) => {
-                    self.collect_inherit(inherit, ctx)?;
-                }
-                ast::Entry::AttrpathValue(value) => {
-                    let attrpath = value.attrpath().unwrap();
-                    let path: Vec<_> = attrpath.attrs().collect();
-                    let expr = value.value().unwrap();
-                    self.insert(&path, expr, ctx)?;
-                }
-            }
-        }
-        Ok(())
-    }
-
-    fn collect_inherit(
-        &mut self,
-        inherit: ast::Inherit,
-        ctx: &mut impl DowngradeContext,
-    ) -> Result<()> {
-        let from = inherit.from().map(|f| f.expr().unwrap());
-        for attr in inherit.attrs() {
-            let span = attr.syntax().text_range();
-            let sym = match &attr {
-                ast::Attr::Ident(ident) => ctx.new_sym(ident.to_string()),
-                ast::Attr::Str(s) => {
-                    let parts = s.normalized_parts();
-                    if parts.len() == 1
-                        && let ast::InterpolPart::Literal(lit) = parts.into_iter().next().unwrap()
-                    {
-                        ctx.new_sym(lit)
-                    } else {
-                        return Err(Error::downgrade_error(
-                            "dynamic attributes not allowed in inherit".to_string(),
-                            ctx.get_current_source(),
-                            span,
-                        ));
-                    }
-                }
-                ast::Attr::Dynamic(_) => {
-                    return Err(Error::downgrade_error(
-                        "dynamic attributes not allowed in inherit".to_string(),
-                        ctx.get_current_source(),
-                        span,
-                    ));
-                }
-            };
-
-            if self.stcs.contains_key(&sym) {
-                return Err(Error::downgrade_error(
-                    format!(
-                        "attribute '{}' already defined",
-                        format_symbol(ctx.get_sym(sym))
-                    ),
-                    ctx.get_current_source(),
-                    span,
-                ));
-            }
-
-            let pending_value = if let Some(ref from_expr) = from {
-                PendingValue::InheritFrom(from_expr.clone(), sym, span)
-            } else {
-                PendingValue::InheritScope(sym, span)
-            };
-
-            self.stcs.insert(sym, (pending_value, span));
-        }
-        Ok(())
-    }
-}
-
-fn make_attrpath_value_entry(path: Vec<ast::Attr>, value: ast::Expr) -> ast::Entry {
-    use rnix::{NixLanguage, SyntaxKind};
-    use rowan::{GreenNodeBuilder, Language, NodeOrToken};
-
-    let mut builder = GreenNodeBuilder::new();
-    builder.start_node(NixLanguage::kind_to_raw(SyntaxKind::NODE_ATTRPATH_VALUE));
-
-    builder.start_node(NixLanguage::kind_to_raw(SyntaxKind::NODE_ATTRPATH));
-    for attr in path {
-        fn add_node(builder: &mut GreenNodeBuilder, node: &rowan::SyntaxNode<NixLanguage>) {
-            for child in node.children_with_tokens() {
-                match child {
-                    NodeOrToken::Node(n) => {
-                        builder.start_node(NixLanguage::kind_to_raw(n.kind()));
-                        add_node(builder, &n);
-                        builder.finish_node();
-                    }
-                    NodeOrToken::Token(t) => {
-                        builder.token(NixLanguage::kind_to_raw(t.kind()), t.text());
-                    }
-                }
-            }
-        }
-        builder.start_node(NixLanguage::kind_to_raw(attr.syntax().kind()));
-        add_node(&mut builder, attr.syntax());
-        builder.finish_node();
-    }
-    builder.finish_node();
-
-    builder.token(NixLanguage::kind_to_raw(SyntaxKind::TOKEN_ASSIGN), "=");
-
-    builder.start_node(NixLanguage::kind_to_raw(value.syntax().kind()));
-    fn add_node_value(builder: &mut GreenNodeBuilder, node: &rowan::SyntaxNode<NixLanguage>) {
-        for child in node.children_with_tokens() {
-            match child {
-                NodeOrToken::Node(n) => {
-                    builder.start_node(NixLanguage::kind_to_raw(n.kind()));
-                    add_node_value(builder, &n);
-                    builder.finish_node();
-                }
-                NodeOrToken::Token(t) => {
-                    builder.token(NixLanguage::kind_to_raw(t.kind()), t.text());
-                }
-            }
-        }
-    }
-    add_node_value(&mut builder, value.syntax());
-    builder.finish_node();
-
-    builder.token(NixLanguage::kind_to_raw(SyntaxKind::TOKEN_SEMICOLON), ";");
-
-    builder.finish_node();
-
-    let green = builder.finish();
-    let node = rowan::SyntaxNode::<NixLanguage>::new_root(green);
-    ast::Entry::cast(node).unwrap()
-}
-
-/// Downgrades the entries of a non-recursive attribute set.
-pub fn downgrade_attrs(
-    attrs: impl ast::HasEntry + AstNode,
-    ctx: &mut impl DowngradeContext,
-) -> Result<AttrSet> {
-    let span = attrs.syntax().text_range();
-    let mut pending = PendingAttrSet::new(span);
-    pending.collect_entries(attrs.entries(), ctx)?;
-    finalize_pending_set::<_, true>(pending, &HashMap::new(), ctx)
-}
-
-/// Downgrades a single attribute key (part of an attribute path).
-pub fn downgrade_attr(attr: ast::Attr, ctx: &mut impl DowngradeContext) -> Result<Attr> {
-    use ast::Attr::*;
-    use ast::InterpolPart::*;
-    match attr {
-        Ident(ident) => Ok(Attr::Str(
-            ctx.new_sym(ident.to_string()),
-            ident.syntax().text_range(),
-        )),
-        Str(string) => {
-            let parts = string.normalized_parts();
-            let span = string.syntax().text_range();
-            if parts.is_empty() {
-                Ok(Attr::Str(ctx.new_sym("".to_string()), span))
-            } else if parts.len() == 1 {
-                match parts.into_iter().next().unwrap() {
-                    Literal(ident) => Ok(Attr::Str(ctx.new_sym(ident), span)),
-                    Interpolation(interpol) => Ok(Attr::Dynamic(
-                        interpol.expr().unwrap().downgrade(ctx)?,
-                        span,
-                    )),
-                }
-            } else {
-                let parts = parts
-                    .into_iter()
-                    .map(|part| match part {
-                        Literal(lit) => Ok(ctx.new_expr(self::Str { val: lit, span }.to_ir())),
-                        Interpolation(interpol) => interpol.expr().unwrap().downgrade(ctx),
-                    })
-                    .collect::<Result<Vec<_>>>()?;
-                Ok(Attr::Dynamic(
-                    ctx.new_expr(ConcatStrings { parts, span }.to_ir()),
-                    span,
-                ))
-            }
-        }
-        Dynamic(dynamic) => Ok(Attr::Dynamic(
-            dynamic.expr().unwrap().downgrade(ctx)?,
-            dynamic.syntax().text_range(),
-        )),
-    }
-}
-
-/// Downgrades an attribute path (e.g., `a.b."${c}".d`) into a `Vec<Attr>`.
-pub fn downgrade_attrpath(
-    attrpath: ast::Attrpath,
-    ctx: &mut impl DowngradeContext,
-) -> Result<Vec<Attr>> {
-    attrpath
-        .attrs()
-        .map(|attr| downgrade_attr(attr, ctx))
-        .collect::<Result<Vec<_>>>()
-}
-
-pub struct PatternBindings {
-    pub body: ExprId,
-    pub required: Vec<SymId>,
-    pub optional: Vec<SymId>,
-}
-
-/// Helper function for Lambda pattern parameters.
-pub fn downgrade_pattern_bindings<Ctx>(
-    pat_entries: impl Iterator<Item = ast::PatEntry>,
-    alias: Option<SymId>,
-    arg: ExprId,
-    ctx: &mut Ctx,
-    body_fn: impl FnOnce(&mut Ctx, &[SymId]) -> Result<ExprId>,
-) -> Result<PatternBindings>
-where
-    Ctx: DowngradeContext,
-{
-    struct Param {
-        sym: SymId,
-        sym_span: TextRange,
-        default: Option<ast::Expr>,
-        span: TextRange,
-    }
-    let mut seen_params = HashSet::new();
-    let (params, mut binding_keys) = pat_entries
-        .into_iter()
-        .map(|entry| {
-            let ident = entry.ident().unwrap();
-            let sym_span = ident.syntax().text_range();
-            let sym = ctx.new_sym(ident.syntax().text().to_string());
-            let default = entry.default();
-            let span = entry.syntax().text_range();
-
-            if !seen_params.insert(sym) {
-                return Err(Error::downgrade_error(
-                    format!("duplicate parameter '{}'", format_symbol(ctx.get_sym(sym))),
-                    ctx.get_current_source(),
-                    span,
-                ));
-            }
-
-            Ok((
-                Param {
-                    sym,
-                    sym_span,
-                    default,
-                    span,
-                },
-                sym,
-            ))
-        })
-        .collect::<Result<(Vec<_>, Vec<_>)>>()?;
-
-    if let Some(alias_sym) = alias {
-        binding_keys.push(alias_sym);
-    }
-
-    let (required, optional) = params.iter().partition_map(|Param { sym, default, .. }| {
-        use itertools::Either::*;
-        if default.is_none() {
-            Left(sym)
-        } else {
-            Right(sym)
-        }
-    });
-
-    let slots: Vec<_> = ctx.reserve_slots(binding_keys.len()).collect();
-    let let_bindings: HashMap<_, _> = binding_keys
-        .iter()
-        .copied()
-        .zip(slots.iter().copied())
-        .collect();
-
-    for &slot in &slots {
-        let span = synthetic_span();
-        ctx.replace_ir(slot, Thunk { inner: slot, span }.to_ir());
-    }
-
-    ctx.with_let_scope(let_bindings.clone(), |ctx| {
-        for Param {
-            sym,
-            sym_span,
-            default,
-            span,
-        } in params
-        {
-            let slot = *let_bindings.get(&sym).unwrap();
-
-            let default = if let Some(default) = default {
-                let default = default.clone().downgrade(ctx)?;
-                Some(ctx.maybe_thunk(default))
-            } else {
-                None
-            };
-
-            let select_expr = ctx.new_expr(
-                Select {
-                    expr: arg,
-                    attrpath: vec![Attr::Str(sym, sym_span)],
-                    default,
-                    span,
-                }
-                .to_ir(),
-            );
-            ctx.register_thunk(slot, select_expr);
-        }
-
-        if let Some(alias_sym) = alias {
-            let slot = *let_bindings.get(&alias_sym).unwrap();
-            ctx.register_thunk(slot, arg);
-        }
-
-        let body = body_fn(ctx, &binding_keys)?;
-
-        Ok(PatternBindings {
-            body,
-            required,
-            optional,
-        })
-    })
-}
-
-/// Downgrades a `let...in` expression. This is a special case of rec attrs
-/// that disallows dynamic attributes and has a body expression.
-pub fn downgrade_let_bindings<Ctx, F>(
-    entries: Vec<ast::Entry>,
-    ctx: &mut Ctx,
-    span: TextRange,
-    body_fn: F,
-) -> Result<ExprId>
-where
-    Ctx: DowngradeContext,
-    F: FnOnce(&mut Ctx, &[SymId]) -> Result<ExprId>,
-{
-    downgrade_rec_attrs_impl::<_, _, false>(entries, ctx, span, |ctx, binding_keys, _dyns| {
-        body_fn(ctx, binding_keys)
-    })
-}
-
-/// Downgrades a `rec` attribute set.
-pub fn downgrade_rec_bindings<Ctx>(
-    entries: Vec<ast::Entry>,
-    ctx: &mut Ctx,
-    span: TextRange,
-) -> Result<ExprId>
-where
-    Ctx: DowngradeContext,
-{
-    downgrade_rec_attrs_impl::<_, _, true>(entries, ctx, span, |ctx, binding_keys, dyns| {
-        let mut attrs = AttrSet {
-            stcs: HashMap::new(),
-            dyns: dyns.to_vec(),
-            span,
-        };
-
-        for sym in binding_keys {
-            let expr = ctx.lookup(*sym, synthetic_span())?;
-            attrs.stcs.insert(*sym, (expr, synthetic_span()));
-        }
-
-        Ok(ctx.new_expr(attrs.to_ir()))
-    })
-}
-
-/// Core implementation for recursive bindings (rec attrs and let-in).
-/// ALLOW_DYN controls whether dynamic attributes are allowed.
-fn downgrade_rec_attrs_impl<Ctx, F, const ALLOW_DYN: bool>(
-    entries: Vec<ast::Entry>,
-    ctx: &mut Ctx,
-    span: TextRange,
-    body_fn: F,
-) -> Result<ExprId>
-where
-    Ctx: DowngradeContext,
-    F: FnOnce(&mut Ctx, &[SymId], &[(ExprId, ExprId, TextRange)]) -> Result<ExprId>,
-{
-    let mut pending = PendingAttrSet::new(span);
-    pending.collect_entries(entries.iter().cloned(), ctx)?;
-
-    let binding_syms = collect_binding_syms::<_, ALLOW_DYN>(&pending, ctx)?;
-
-    let inherit_lookups = collect_inherit_lookups(&entries, ctx)?;
-
-    let binding_keys: Vec<_> = binding_syms.into_iter().collect();
-    let slots: Vec<_> = ctx.reserve_slots(binding_keys.len()).collect();
-    let let_bindings: HashMap<_, _> = binding_keys
-        .iter()
-        .copied()
-        .zip(slots.iter().copied())
-        .collect();
-
-    for &slot in &slots {
-        let slot_span = synthetic_span();
-        ctx.replace_ir(
-            slot,
-            Thunk {
-                inner: slot,
-                span: slot_span,
-            }
-            .to_ir(),
-        );
-    }
-
-    ctx.with_let_scope(let_bindings.clone(), |ctx| {
-        let finalized = finalize_pending_set::<_, ALLOW_DYN>(pending, &inherit_lookups, ctx)?;
-
-        for (sym, slot) in binding_keys.iter().copied().zip(slots.iter()) {
-            if let Some(&(expr, _)) = finalized.stcs.get(&sym) {
-                ctx.register_thunk(*slot, expr);
-            } else {
-                return Err(Error::internal(format!(
-                    "binding '{}' not found",
-                    format_symbol(ctx.get_sym(sym))
-                )));
-            }
-        }
-
-        body_fn(ctx, &binding_keys, &finalized.dyns)
-    })
-}
-
-/// Collects `inherit x` lookups from the outer scope before entering the rec scope.
-fn collect_inherit_lookups<Ctx: DowngradeContext>(
-    entries: &[ast::Entry],
-    ctx: &mut Ctx,
-) -> Result<HashMap<SymId, (ExprId, TextRange)>> {
-    let mut inherit_lookups = HashMap::new();
-    for entry in entries {
-        if let ast::Entry::Inherit(inherit) = entry
-            && inherit.from().is_none()
-        {
-            for attr in inherit.attrs() {
-                if let ast::Attr::Ident(ident) = attr {
-                    let attr_span = ident.syntax().text_range();
-                    let sym = ctx.new_sym(ident.to_string());
-                    let expr = ctx.lookup(sym, attr_span)?;
-                    inherit_lookups.insert(sym, (expr, attr_span));
-                }
-            }
-        }
-    }
-    Ok(inherit_lookups)
-}
-
-/// Collects binding symbols from a pending set, checking for duplicates.
-fn collect_binding_syms<Ctx: DowngradeContext, const ALLOW_DYN: bool>(
-    pending: &PendingAttrSet,
-    ctx: &mut Ctx,
-) -> Result<HashSet<SymId>> {
-    let mut binding_syms = HashSet::new();
-
-    for (sym, (_, span)) in &pending.stcs {
-        if !binding_syms.insert(*sym) {
-            return Err(Error::downgrade_error(
-                format!(
-                    "attribute '{}' already defined",
-                    format_symbol(ctx.get_sym(*sym))
-                ),
-                ctx.get_current_source(),
-                *span,
-            ));
-        }
-    }
-
-    Ok(binding_syms)
-}
-
-/// Unified finalize function for PendingAttrSet.
-/// ALLOW_DYN controls whether dynamic attributes are allowed.
-fn finalize_pending_set<Ctx: DowngradeContext, const ALLOW_DYN: bool>(
-    pending: PendingAttrSet,
-    inherit_lookups: &HashMap<SymId, (ExprId, TextRange)>,
-    ctx: &mut Ctx,
-) -> Result<AttrSet> {
-    let mut stcs = HashMap::new();
-    let mut dyns = Vec::new();
-
-    for (sym, (value, value_span)) in pending.stcs {
-        let expr_id = finalize_pending_value::<_, ALLOW_DYN>(value, inherit_lookups, ctx)?;
-        stcs.insert(sym, (expr_id, value_span));
-    }
-
-    if ALLOW_DYN {
-        for (attr, value, value_span) in pending.dyns {
-            let key_id = downgrade_attr(attr, ctx)?;
-            let key_expr = match key_id {
-                Attr::Dynamic(id, _) => id,
-                Attr::Str(sym, attr_span) => ctx.new_expr(
-                    Str {
-                        val: ctx.get_sym(sym).to_string(),
-                        span: attr_span,
-                    }
-                    .to_ir(),
-                ),
-            };
-            let value_id = finalize_pending_value::<_, ALLOW_DYN>(value, inherit_lookups, ctx)?;
-            dyns.push((key_expr, value_id, value_span));
-        }
-    }
-
-    Ok(AttrSet {
-        stcs,
-        dyns,
-        span: pending.span,
-    })
-}
-
-/// Unified finalize function for PendingValue.
-/// ALLOW_DYN controls whether dynamic attributes are allowed.
-fn finalize_pending_value<Ctx: DowngradeContext, const ALLOW_DYN: bool>(
-    value: PendingValue,
-    inherit_lookups: &HashMap<SymId, (ExprId, TextRange)>,
-    ctx: &mut Ctx,
-) -> Result<ExprId> {
-    match value {
-        PendingValue::Expr(expr) => {
-            if !ALLOW_DYN {
-                check_no_dynamic_attrs(&expr, ctx)?;
-            }
-            let id = Downgrade::downgrade(expr, ctx)?;
-            Ok(ctx.maybe_thunk(id))
-        }
-        PendingValue::InheritFrom(from_expr, sym, span) => {
-            let from_id = Downgrade::downgrade(from_expr, ctx)?;
-            let select = Select {
-                expr: from_id,
-                attrpath: vec![Attr::Str(sym, span)],
-                default: None,
-                span,
-            };
-            let select_id = ctx.new_expr(select.to_ir());
-            Ok(ctx.maybe_thunk(select_id))
-        }
-        PendingValue::InheritScope(sym, span) => {
-            if let Some(&(expr, _)) = inherit_lookups.get(&sym) {
-                Ok(ctx.maybe_thunk(expr))
-            } else {
-                let lookup_id = ctx.lookup(sym, span)?;
-                Ok(ctx.maybe_thunk(lookup_id))
-            }
-        }
-        PendingValue::Set(set) => {
-            let attrset = finalize_pending_set::<_, ALLOW_DYN>(set, inherit_lookups, ctx)?;
-            Ok(ctx.new_expr(attrset.to_ir()))
-        }
-        PendingValue::ExtendedRecAttrSet {
-            base,
-            extensions,
-            span,
-        } => {
-            let mut all_entries: Vec<_> = base.entries().collect();
-            all_entries.extend(extensions);
-            downgrade_rec_bindings(all_entries, ctx, span)
-        }
-    }
-}
-
-/// Check that an expression doesn't contain dynamic attributes (for let bindings).
-fn check_no_dynamic_attrs(expr: &ast::Expr, ctx: &impl DowngradeContext) -> Result<()> {
-    let ast::Expr::AttrSet(attrset) = expr else {
-        return Ok(())
-    };
-    for v in attrset.attrpath_values() {
-        v.attrpath().unwrap().attrs().try_for_each(|attr| {
-            if let ast::Attr::Dynamic(dyn_attr) = attr {
-                Err(Error::downgrade_error(
-                    "dynamic attributes not allowed in let bindings".to_string(),
-                    ctx.get_current_source(),
-                    dyn_attr.syntax().text_range(),
-                ))
-            } else {
-                Ok(())
-            }
-        })?;
-    }
-    Ok(())
-}

nix-js/src/lib.rs

@@ -5,13 +5,18 @@ pub mod error;
 pub mod logging;
 pub mod value;
 
+mod bytecode;
 mod codegen;
+mod derivation;
+mod disassembler;
+mod downgrade;
 mod fetcher;
 mod ir;
 mod nar;
-mod nix_hash;
+mod nix_utils;
 mod runtime;
 mod store;
+mod string_context;
 
 #[global_allocator]
 static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;

nix-js/src/logging.rs

@@ -1,5 +1,6 @@
 use std::env;
 use std::io::IsTerminal;
+
 use tracing_subscriber::{EnvFilter, Layer, fmt, layer::SubscriberExt, util::SubscriberInitExt};
 
 pub fn init_logging() {

nix-js/src/main.rs

@@ -0,0 +1,187 @@
+use std::path::PathBuf;
+use std::process::exit;
+
+use anyhow::Result;
+use clap::{Args, Parser, Subcommand};
+use hashbrown::HashSet;
+use nix_js::context::Context;
+use nix_js::error::Source;
+use rustyline::DefaultEditor;
+use rustyline::error::ReadlineError;
+
+#[derive(Parser)]
+#[command(name = "nix-js", about = "Nix expression evaluator")]
+struct Cli {
+    #[cfg(feature = "inspector")]
+    #[arg(long, value_name = "HOST:PORT", num_args = 0..=1, default_missing_value = "127.0.0.1:9229")]
+    inspect: Option<String>,
+
+    #[cfg(feature = "inspector")]
+    #[arg(long, value_name = "HOST:PORT", num_args = 0..=1, default_missing_value = "127.0.0.1:9229")]
+    inspect_brk: Option<String>,
+
+    #[command(subcommand)]
+    command: Command,
+}
+
+#[derive(Subcommand)]
+enum Command {
+    Compile {
+        #[clap(flatten)]
+        source: ExprSource,
+        #[arg(long)]
+        silent: bool,
+    },
+    Eval {
+        #[clap(flatten)]
+        source: ExprSource,
+    },
+    Repl,
+}
+
+#[derive(Args)]
+#[group(required = true, multiple = false)]
+struct ExprSource {
+    #[clap(short, long)]
+    expr: Option<String>,
+    #[clap(short, long)]
+    file: Option<PathBuf>,
+}
+
+fn create_context(#[cfg(feature = "inspector")] cli: &Cli) -> Result<Context> {
+    #[cfg(feature = "inspector")]
+    {
+        let (addr_str, wait) = if let Some(ref addr) = cli.inspect_brk {
+            (Some(addr.as_str()), true)
+        } else if let Some(ref addr) = cli.inspect {
+            (Some(addr.as_str()), false)
+        } else {
+            (None, false)
+        };
+
+        if let Some(addr_str) = addr_str {
+            let addr: std::net::SocketAddr = addr_str
+                .parse()
+                .map_err(|e| anyhow::anyhow!("invalid inspector address '{}': {}", addr_str, e))?;
+            return Ok(Context::new_with_inspector(addr, wait)?);
+        }
+    }
+    Ok(Context::new()?)
+}
+
+fn run_compile(context: &mut Context, src: ExprSource, silent: bool) -> Result<()> {
+    let src = if let Some(expr) = src.expr {
+        Source::new_eval(expr)?
+    } else if let Some(file) = src.file {
+        Source::new_file(file)?
+    } else {
+        unreachable!()
+    };
+    match context.compile_bytecode(src) {
+        Ok(compiled) => {
+            if !silent {
+                println!("{}", context.disassemble_colored(&compiled));
+            }
+        }
+        Err(err) => {
+            eprintln!("{:?}", miette::Report::new(*err));
+            exit(1);
+        }
+    };
+    #[cfg(feature = "inspector")]
+    context.wait_for_inspector_disconnect();
+    Ok(())
+}
+
+fn run_eval(context: &mut Context, src: ExprSource) -> Result<()> {
+    let src = if let Some(expr) = src.expr {
+        Source::new_eval(expr)?
+    } else if let Some(file) = src.file {
+        Source::new_file(file)?
+    } else {
+        unreachable!()
+    };
+    match context.eval_deep(src) {
+        Ok(value) => {
+            println!("{}", value.display_compat());
+        }
+        Err(err) => {
+            eprintln!("{:?}", miette::Report::new(*err));
+            exit(1);
+        }
+    };
+    #[cfg(feature = "inspector")]
+    context.wait_for_inspector_disconnect();
+    Ok(())
+}
+
+fn run_repl(context: &mut Context) -> Result<()> {
+    let mut rl = DefaultEditor::new()?;
+    let mut scope = HashSet::new();
+    const RE: ere::Regex<3> = ere::compile_regex!("^[ \t]*([a-zA-Z_][a-zA-Z0-9_'-]*)[ \t]*(.*)$");
+    loop {
+        let readline = rl.readline("nix-js-repl> ");
+        match readline {
+            Ok(line) => {
+                if line.trim().is_empty() {
+                    continue;
+                }
+                let _ = rl.add_history_entry(line.as_str());
+                if let Some([Some(_), Some(ident), Some(rest)]) = RE.exec(&line) {
+                    if let Some(expr) = rest.strip_prefix('=') {
+                        let expr = expr.trim_start();
+                        if expr.is_empty() {
+                            eprintln!("Error: missing expression after '='");
+                            continue;
+                        }
+                        match context.add_binding(ident, expr, &mut scope) {
+                            Ok(value) => println!("{} = {}", ident, value),
+                            Err(err) => eprintln!("{:?}", miette::Report::new(*err)),
+                        }
+                    } else {
+                        let src = Source::new_repl(line)?;
+                        match context.eval_repl(src, &scope) {
+                            Ok(value) => println!("{value}"),
+                            Err(err) => eprintln!("{:?}", miette::Report::new(*err)),
+                        }
+                    }
+                } else {
+                    let src = Source::new_repl(line)?;
+                    match context.eval_shallow(src) {
+                        Ok(value) => println!("{value}"),
+                        Err(err) => eprintln!("{:?}", miette::Report::new(*err)),
+                    }
+                }
+            }
+            Err(ReadlineError::Interrupted) => {
+                println!();
+            }
+            Err(ReadlineError::Eof) => {
+                println!("CTRL-D");
+                break;
+            }
+            Err(err) => {
+                eprintln!("Error: {err:?}");
+                break;
+            }
+        }
+    }
+    Ok(())
+}
+
+fn main() -> Result<()> {
+    nix_js::logging::init_logging();
+
+    let cli = Cli::parse();
+
+    let mut context = create_context(
+        #[cfg(feature = "inspector")]
+        &cli,
+    )?;
+
+    match cli.command {
+        Command::Compile { source, silent } => run_compile(&mut context, source, silent),
+        Command::Eval { source } => run_eval(&mut context, source),
+        Command::Repl => run_repl(&mut context),
+    }
+}

nix-js/src/nar.rs

@@ -1,18 +1,19 @@
-use nix_nar::Encoder;
-use sha2::{Digest, Sha256};
 use std::io::Read;
 use std::path::Path;
 
+use nix_nar::Encoder;
+use sha2::{Digest, Sha256};
+
 use crate::error::{Error, Result};
 
-pub fn compute_nar_hash(path: &Path) -> Result<String> {
+pub fn compute_nar_hash(path: &Path) -> Result<[u8; 32]> {
     let mut hasher = Sha256::new();
     std::io::copy(
         &mut Encoder::new(path).map_err(|err| Error::internal(err.to_string()))?,
         &mut hasher,
     )
     .map_err(|err| Error::internal(err.to_string()))?;
-    Ok(hex::encode(hasher.finalize()))
+    Ok(hasher.finalize().into())
 }
 
 pub fn pack_nar(path: &Path) -> Result<Vec<u8>> {
@@ -27,17 +28,19 @@ pub fn pack_nar(path: &Path) -> Result<Vec<u8>> {
 #[cfg(test)]
 #[allow(clippy::unwrap_used)]
 mod tests {
-    use super::*;
     use std::fs;
+
     use tempfile::TempDir;
 
-    #[test]
+    use super::*;
+
+    #[test_log::test]
     fn test_simple_file() {
         let temp = TempDir::new().unwrap();
         let file_path = temp.path().join("test.txt");
         fs::write(&file_path, "hello").unwrap();
 
-        let hash = compute_nar_hash(&file_path).unwrap();
+        let hash = hex::encode(compute_nar_hash(&file_path).unwrap());
         assert_eq!(
             hash,
             "0a430879c266f8b57f4092a0f935cf3facd48bbccde5760d4748ca405171e969"
@@ -46,13 +49,13 @@ mod tests {
         assert_eq!(hash.len(), 64);
     }
 
-    #[test]
+    #[test_log::test]
     fn test_directory() {
         let temp = TempDir::new().unwrap();
         fs::write(temp.path().join("a.txt"), "aaa").unwrap();
         fs::write(temp.path().join("b.txt"), "bbb").unwrap();
 
-        let hash = compute_nar_hash(temp.path()).unwrap();
+        let hash = hex::encode(compute_nar_hash(temp.path()).unwrap());
         assert_eq!(
             hash,
             "0036c14209749bc9b9631e2077b108b701c322ab53853cd26f2746268a86fc0f"

nix-js/src/nix_hash.rs

@@ -1,122 +0,0 @@
-use sha2::{Digest, Sha256};
-
-const NIX_BASE32_CHARS: &[u8; 32] = b"0123456789abcdfghijklmnpqrsvwxyz";
-
-pub fn sha256_hex(data: &str) -> String {
-    let mut hasher = Sha256::new();
-    hasher.update(data.as_bytes());
-    hex::encode(hasher.finalize())
-}
-
-pub fn compress_hash(hash: &[u8; 32], new_size: usize) -> Vec<u8> {
-    let mut result = vec![0u8; new_size];
-    for i in 0..32 {
-        result[i % new_size] ^= hash[i];
-    }
-    result
-}
-
-pub fn nix_base32_encode(bytes: &[u8]) -> String {
-    let len = (bytes.len() * 8 - 1) / 5 + 1;
-    let mut result = String::with_capacity(len);
-
-    for n in (0..len).rev() {
-        let b = n * 5;
-        let i = b / 8;
-        let j = b % 8;
-
-        let c = if i >= bytes.len() {
-            0
-        } else {
-            let mut c = (bytes[i] as u16) >> j;
-            if j > 3 && i + 1 < bytes.len() {
-                c |= (bytes[i + 1] as u16) << (8 - j);
-            }
-            c
-        };
-
-        result.push(NIX_BASE32_CHARS[(c & 0x1f) as usize] as char);
-    }
-
-    result
-}
-
-pub fn make_store_path(store_dir: &str, ty: &str, hash_hex: &str, name: &str) -> String {
-    let s = format!("{}:sha256:{}:{}:{}", ty, hash_hex, store_dir, name);
-
-    let mut hasher = Sha256::new();
-    hasher.update(s.as_bytes());
-    let hash: [u8; 32] = hasher.finalize().into();
-
-    let compressed = compress_hash(&hash, 20);
-    let encoded = nix_base32_encode(&compressed);
-
-    format!("{}/{}-{}", store_dir, encoded, name)
-}
-
-pub fn output_path_name(drv_name: &str, output_name: &str) -> String {
-    if output_name == "out" {
-        drv_name.to_string()
-    } else {
-        format!("{}-{}", drv_name, output_name)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_nix_base32_encode() {
-        let bytes = [0xFF, 0xFF, 0xFF, 0xFF, 0xFF];
-        let encoded = nix_base32_encode(&bytes);
-        assert_eq!(encoded.len(), 8);
-
-        let bytes_zero = [0u8; 20];
-        let encoded_zero = nix_base32_encode(&bytes_zero);
-        assert_eq!(encoded_zero.len(), 32);
-        assert!(encoded_zero.chars().all(|c| c == '0'));
-    }
-
-    #[test]
-    fn test_compress_hash() {
-        let hash = [0u8; 32];
-        let compressed = compress_hash(&hash, 20);
-        assert_eq!(compressed.len(), 20);
-        assert!(compressed.iter().all(|&b| b == 0));
-
-        let hash_ones = [0xFF; 32];
-        let compressed_ones = compress_hash(&hash_ones, 20);
-        assert_eq!(compressed_ones.len(), 20);
-    }
-
-    #[test]
-    fn test_sha256_hex() {
-        let data = "hello world";
-        let hash = sha256_hex(data);
-        assert_eq!(hash.len(), 64);
-        assert_eq!(
-            hash,
-            "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9"
-        );
-    }
-
-    #[test]
-    fn test_output_path_name() {
-        assert_eq!(output_path_name("hello", "out"), "hello");
-        assert_eq!(output_path_name("hello", "dev"), "hello-dev");
-        assert_eq!(output_path_name("hello", "doc"), "hello-doc");
-    }
-
-    #[test]
-    fn test_make_store_path() {
-        let path = make_store_path("/nix/store", "output:out", "abc123", "hello");
-        assert!(path.starts_with("/nix/store/"));
-        assert!(path.ends_with("-hello"));
-
-        let hash_parts: Vec<&str> = path.split('/').collect();
-        assert_eq!(hash_parts.len(), 4);
-        let name_part = hash_parts[3];
-        assert!(name_part.contains('-'));
-    }
-}

nix-js/src/nix_utils.rs

@@ -0,0 +1,21 @@
+use nix_compat::store_path::compress_hash;
+use sha2::{Digest as _, Sha256};
+
+pub fn sha256_hex(data: &[u8]) -> String {
+    let mut hasher = Sha256::new();
+    hasher.update(data);
+    hex::encode(hasher.finalize())
+}
+
+pub fn make_store_path(store_dir: &str, ty: &str, hash_hex: &str, name: &str) -> String {
+    let s = format!("{}:sha256:{}:{}:{}", ty, hash_hex, store_dir, name);
+
+    let mut hasher = Sha256::new();
+    hasher.update(s.as_bytes());
+    let hash: [u8; 32] = hasher.finalize().into();
+
+    let compressed = compress_hash::<20>(&hash);
+    let encoded = nix_compat::nixbase32::encode(&compressed);
+
+    format!("{}/{}-{}", store_dir, encoded, name)
+}

nix-js/src/runtime/corepkgs/derivation.nix

@@ -0,0 +1,31 @@
+drvAttrs@{
+  outputs ? [ "out" ],
+  ...
+}:
+
+let
+
+  strict = derivationStrict drvAttrs;
+
+  commonAttrs =
+    drvAttrs
+    // (builtins.listToAttrs outputsList)
+    // {
+      all = map (x: x.value) outputsList;
+      inherit drvAttrs;
+    };
+
+  outputToAttrListElement = outputName: {
+    name = outputName;
+    value = commonAttrs // {
+      outPath = builtins.getAttr outputName strict;
+      drvPath = strict.drvPath;
+      type = "derivation";
+      inherit outputName;
+    };
+  };
+
+  outputsList = map outputToAttrListElement outputs;
+
+in
+(builtins.head outputsList).value

nix-js/src/runtime/inspector.rs

@@ -0,0 +1,493 @@
+// Copyright 2018-2025 the Deno authors. MIT license.
+
+// Alias for the future `!` type.
+use core::convert::Infallible as Never;
+use std::cell::RefCell;
+use std::net::SocketAddr;
+use std::pin::pin;
+use std::process;
+use std::rc::Rc;
+use std::task::Poll;
+use std::thread;
+
+use deno_core::InspectorMsg;
+use deno_core::InspectorSessionChannels;
+use deno_core::InspectorSessionKind;
+use deno_core::InspectorSessionProxy;
+use deno_core::JsRuntimeInspector;
+use deno_core::anyhow::Context;
+use deno_core::futures::channel::mpsc;
+use deno_core::futures::channel::mpsc::UnboundedReceiver;
+use deno_core::futures::channel::mpsc::UnboundedSender;
+use deno_core::futures::channel::oneshot;
+use deno_core::futures::prelude::*;
+use deno_core::futures::stream::StreamExt;
+use deno_core::serde_json::Value;
+use deno_core::serde_json::json;
+use deno_core::unsync::spawn;
+use deno_core::url::Url;
+use fastwebsockets::Frame;
+use fastwebsockets::OpCode;
+use fastwebsockets::WebSocket;
+use hashbrown::HashMap;
+use hyper::body::Bytes;
+use hyper_util::rt::TokioIo;
+use tokio::net::TcpListener;
+use tokio::sync::broadcast;
+use uuid::Uuid;
+
+/// Websocket server that is used to proxy connections from
+/// devtools to the inspector.
+pub struct InspectorServer {
+    pub host: SocketAddr,
+    register_inspector_tx: UnboundedSender<InspectorInfo>,
+    shutdown_server_tx: Option<broadcast::Sender<()>>,
+    thread_handle: Option<thread::JoinHandle<()>>,
+}
+
+impl InspectorServer {
+    pub fn new(host: SocketAddr, name: &'static str) -> Result<Self, anyhow::Error> {
+        let (register_inspector_tx, register_inspector_rx) = mpsc::unbounded::<InspectorInfo>();
+
+        let (shutdown_server_tx, shutdown_server_rx) = broadcast::channel(1);
+
+        let tcp_listener = std::net::TcpListener::bind(host)
+            .with_context(|| format!("Failed to bind inspector server socket at {}", host))?;
+        tcp_listener.set_nonblocking(true)?;
+
+        let thread_handle = thread::spawn(move || {
+            let rt = tokio::runtime::Builder::new_current_thread()
+                .enable_all()
+                .build()
+                .expect("failed to build tokio runtime");
+            let local = tokio::task::LocalSet::new();
+            local.block_on(
+                &rt,
+                server(
+                    tcp_listener,
+                    register_inspector_rx,
+                    shutdown_server_rx,
+                    name,
+                ),
+            )
+        });
+
+        Ok(Self {
+            host,
+            register_inspector_tx,
+            shutdown_server_tx: Some(shutdown_server_tx),
+            thread_handle: Some(thread_handle),
+        })
+    }
+
+    pub fn register_inspector(
+        &self,
+        module_url: String,
+        inspector: Rc<JsRuntimeInspector>,
+        wait_for_session: bool,
+    ) {
+        let session_sender = inspector.get_session_sender();
+        let deregister_rx = inspector.add_deregister_handler();
+
+        let info = InspectorInfo::new(
+            self.host,
+            session_sender,
+            deregister_rx,
+            module_url,
+            wait_for_session,
+        );
+        self.register_inspector_tx
+            .unbounded_send(info)
+            .expect("unreachable");
+    }
+}
+
+impl Drop for InspectorServer {
+    fn drop(&mut self) {
+        if let Some(shutdown_server_tx) = self.shutdown_server_tx.take() {
+            shutdown_server_tx
+                .send(())
+                .expect("unable to send shutdown signal");
+        }
+
+        if let Some(thread_handle) = self.thread_handle.take() {
+            thread_handle.join().expect("unable to join thread");
+        }
+    }
+}
+
+fn handle_ws_request(
+    req: http::Request<hyper::body::Incoming>,
+    inspector_map_rc: Rc<RefCell<HashMap<Uuid, InspectorInfo>>>,
+) -> http::Result<http::Response<Box<http_body_util::Full<Bytes>>>> {
+    let (parts, body) = req.into_parts();
+    let req = http::Request::from_parts(parts, ());
+
+    let maybe_uuid = req
+        .uri()
+        .path()
+        .strip_prefix("/ws/")
+        .and_then(|s| Uuid::parse_str(s).ok());
+
+    let Some(uuid) = maybe_uuid else {
+        return http::Response::builder()
+            .status(http::StatusCode::BAD_REQUEST)
+            .body(Box::new(Bytes::from("Malformed inspector UUID").into()));
+    };
+
+    // run in a block to not hold borrow to `inspector_map` for too long
+    let new_session_tx = {
+        let inspector_map = inspector_map_rc.borrow();
+        let maybe_inspector_info = inspector_map.get(&uuid);
+
+        let Some(info) = maybe_inspector_info else {
+            return http::Response::builder()
+                .status(http::StatusCode::NOT_FOUND)
+                .body(Box::new(Bytes::from("Invalid inspector UUID").into()));
+        };
+        info.new_session_tx.clone()
+    };
+    let (parts, _) = req.into_parts();
+    let mut req = http::Request::from_parts(parts, body);
+
+    let Ok((resp, upgrade_fut)) = fastwebsockets::upgrade::upgrade(&mut req) else {
+        return http::Response::builder()
+            .status(http::StatusCode::BAD_REQUEST)
+            .body(Box::new(
+                Bytes::from("Not a valid Websocket Request").into(),
+            ));
+    };
+
+    // spawn a task that will wait for websocket connection and then pump messages between
+    // the socket and inspector proxy
+    spawn(async move {
+        let websocket = match upgrade_fut.await {
+            Ok(w) => w,
+            Err(err) => {
+                eprintln!(
+                    "Inspector server failed to upgrade to WS connection: {:?}",
+                    err
+                );
+                return;
+            }
+        };
+
+        // The 'outbound' channel carries messages sent to the websocket.
+        let (outbound_tx, outbound_rx) = mpsc::unbounded();
+        // The 'inbound' channel carries messages received from the websocket.
+        let (inbound_tx, inbound_rx) = mpsc::unbounded();
+
+        let inspector_session_proxy = InspectorSessionProxy {
+            channels: InspectorSessionChannels::Regular {
+                tx: outbound_tx,
+                rx: inbound_rx,
+            },
+            kind: InspectorSessionKind::NonBlocking {
+                wait_for_disconnect: true,
+            },
+        };
+
+        eprintln!("Debugger session started.");
+        let _ = new_session_tx.unbounded_send(inspector_session_proxy);
+        pump_websocket_messages(websocket, inbound_tx, outbound_rx).await;
+    });
+
+    let (parts, _body) = resp.into_parts();
+    let resp = http::Response::from_parts(parts, Box::new(http_body_util::Full::new(Bytes::new())));
+    Ok(resp)
+}
+
+fn handle_json_request(
+    inspector_map: Rc<RefCell<HashMap<Uuid, InspectorInfo>>>,
+    host: Option<String>,
+) -> http::Result<http::Response<Box<http_body_util::Full<Bytes>>>> {
+    let data = inspector_map
+        .borrow()
+        .values()
+        .map(move |info| info.get_json_metadata(&host))
+        .collect::<Vec<_>>();
+    let body: http_body_util::Full<Bytes> =
+        Bytes::from(serde_json::to_string(&data).expect("unreachable")).into();
+    http::Response::builder()
+        .status(http::StatusCode::OK)
+        .header(http::header::CONTENT_TYPE, "application/json")
+        .body(Box::new(body))
+}
+
+fn handle_json_version_request(
+    version_response: Value,
+) -> http::Result<http::Response<Box<http_body_util::Full<Bytes>>>> {
+    let body = Box::new(http_body_util::Full::from(
+        serde_json::to_string(&version_response).expect("unreachable"),
+    ));
+
+    http::Response::builder()
+        .status(http::StatusCode::OK)
+        .header(http::header::CONTENT_TYPE, "application/json")
+        .body(body)
+}
+
+async fn server(
+    listener: std::net::TcpListener,
+    register_inspector_rx: UnboundedReceiver<InspectorInfo>,
+    shutdown_server_rx: broadcast::Receiver<()>,
+    name: &str,
+) {
+    let inspector_map_ = Rc::new(RefCell::new(HashMap::<Uuid, InspectorInfo>::new()));
+
+    let inspector_map = Rc::clone(&inspector_map_);
+    let register_inspector_handler =
+        listen_for_new_inspectors(register_inspector_rx, inspector_map.clone()).boxed_local();
+
+    let inspector_map = Rc::clone(&inspector_map_);
+    let deregister_inspector_handler = future::poll_fn(|cx| {
+        inspector_map
+            .borrow_mut()
+            .retain(|_, info| info.deregister_rx.poll_unpin(cx) == Poll::Pending);
+        Poll::<Never>::Pending
+    })
+    .boxed_local();
+
+    let json_version_response = json!({
+        "Browser": name,
+        "Protocol-Version": "1.3",
+        "V8-Version": deno_core::v8::VERSION_STRING,
+    });
+
+    // Create the server manually so it can use the Local Executor
+    let listener = match TcpListener::from_std(listener) {
+        Ok(l) => l,
+        Err(err) => {
+            eprintln!("Cannot create async listener from std listener: {:?}", err);
+            return;
+        }
+    };
+
+    let server_handler = async move {
+        loop {
+            let mut rx = shutdown_server_rx.resubscribe();
+            let mut shutdown_rx = pin!(rx.recv());
+            let mut accept = pin!(listener.accept());
+
+            let stream = tokio::select! {
+                accept_result =
+                    &mut accept => {
+                        match accept_result {
+                            Ok((s, _)) => s,
+                            Err(err) => {
+                                eprintln!("Failed to accept inspector connection: {:?}", err);
+                                continue;
+                            }
+                        }
+                    },
+
+                    _ = &mut shutdown_rx => {
+                        break;
+                    }
+            };
+            let io = TokioIo::new(stream);
+
+            let inspector_map = Rc::clone(&inspector_map_);
+            let json_version_response = json_version_response.clone();
+            let mut shutdown_server_rx = shutdown_server_rx.resubscribe();
+
+            let service =
+                hyper::service::service_fn(move |req: http::Request<hyper::body::Incoming>| {
+                    future::ready({
+                        // If the host header can make a valid URL, use it
+                        let host = req
+                            .headers()
+                            .get("host")
+                            .and_then(|host| host.to_str().ok())
+                            .and_then(|host| Url::parse(&format!("http://{host}")).ok())
+                            .and_then(|url| match (url.host(), url.port()) {
+                                (Some(host), Some(port)) => Some(format!("{host}:{port}")),
+                                (Some(host), None) => Some(format!("{host}")),
+                                _ => None,
+                            });
+                        match (req.method(), req.uri().path()) {
+                            (&http::Method::GET, path) if path.starts_with("/ws/") => {
+                                handle_ws_request(req, Rc::clone(&inspector_map))
+                            }
+                            (&http::Method::GET, "/json/version") => {
+                                handle_json_version_request(json_version_response.clone())
+                            }
+                            (&http::Method::GET, "/json") => {
+                                handle_json_request(Rc::clone(&inspector_map), host)
+                            }
+                            (&http::Method::GET, "/json/list") => {
+                                handle_json_request(Rc::clone(&inspector_map), host)
+                            }
+                            _ => http::Response::builder()
+                                .status(http::StatusCode::NOT_FOUND)
+                                .body(Box::new(http_body_util::Full::new(Bytes::from(
+                                    "Not Found",
+                                )))),
+                        }
+                    })
+                });
+
+            deno_core::unsync::spawn(async move {
+                let server = hyper::server::conn::http1::Builder::new();
+
+                let mut conn = pin!(server.serve_connection(io, service).with_upgrades());
+                let mut shutdown_rx = pin!(shutdown_server_rx.recv());
+
+                tokio::select! {
+                    result = conn.as_mut() => {
+                        if let Err(err) = result {
+                            eprintln!("Failed to serve connection: {:?}", err);
+                        }
+                    },
+                    _ = &mut shutdown_rx => {
+                        conn.as_mut().graceful_shutdown();
+                        let _ = conn.await;
+                    }
+                }
+            });
+        }
+    }
+    .boxed_local();
+
+    tokio::select! {
+        _ = register_inspector_handler => {},
+        _ = deregister_inspector_handler => unreachable!(),
+        _ = server_handler => {},
+    }
+}
+
+async fn listen_for_new_inspectors(
+    mut register_inspector_rx: UnboundedReceiver<InspectorInfo>,
+    inspector_map: Rc<RefCell<HashMap<Uuid, InspectorInfo>>>,
+) {
+    while let Some(info) = register_inspector_rx.next().await {
+        eprintln!(
+            "Debugger listening on {}",
+            info.get_websocket_debugger_url(&info.host.to_string())
+        );
+        eprintln!("Visit chrome://inspect to connect to the debugger.");
+        if info.wait_for_session {
+            eprintln!("nix-js is waiting for debugger to connect.");
+        }
+        if inspector_map.borrow_mut().insert(info.uuid, info).is_some() {
+            panic!("Inspector UUID already in map");
+        }
+    }
+}
+
+/// The pump future takes care of forwarding messages between the websocket
+/// and channels. It resolves when either side disconnects, ignoring any
+/// errors.
+///
+/// The future proxies messages sent and received on a WebSocket
+/// to a UnboundedSender/UnboundedReceiver pair. We need these "unbounded" channel ends to sidestep
+/// Tokio's task budget, which causes issues when JsRuntimeInspector::poll_sessions()
+/// needs to block the thread because JavaScript execution is paused.
+///
+/// This works because UnboundedSender/UnboundedReceiver are implemented in the
+/// 'futures' crate, therefore they can't participate in Tokio's cooperative
+/// task yielding.
+async fn pump_websocket_messages(
+    mut websocket: WebSocket<TokioIo<hyper::upgrade::Upgraded>>,
+    inbound_tx: UnboundedSender<String>,
+    mut outbound_rx: UnboundedReceiver<InspectorMsg>,
+) {
+    'pump: loop {
+        tokio::select! {
+            Some(msg) = outbound_rx.next() => {
+                let msg = Frame::text(msg.content.into_bytes().into());
+                let _ = websocket.write_frame(msg).await;
+            }
+            Ok(msg) = websocket.read_frame() => {
+                match msg.opcode {
+                    OpCode::Text => {
+                        if let Ok(s) = String::from_utf8(msg.payload.to_vec()) {
+                            let _ = inbound_tx.unbounded_send(s);
+                        }
+                    }
+                    OpCode::Close => {
+                        // Users don't care if there was an error coming from debugger,
+                        // just about the fact that debugger did disconnect.
+                        eprintln!("Debugger session ended");
+                        break 'pump;
+                    }
+                    _ => {
+                        // Ignore other messages.
+                    }
+                }
+            }
+            else => {
+                break 'pump;
+            }
+        }
+    }
+}
+
+/// Inspector information that is sent from the isolate thread to the server
+/// thread when a new inspector is created.
+pub struct InspectorInfo {
+    pub host: SocketAddr,
+    pub uuid: Uuid,
+    pub thread_name: Option<String>,
+    pub new_session_tx: UnboundedSender<InspectorSessionProxy>,
+    pub deregister_rx: oneshot::Receiver<()>,
+    pub url: String,
+    pub wait_for_session: bool,
+}
+
+impl InspectorInfo {
+    pub fn new(
+        host: SocketAddr,
+        new_session_tx: mpsc::UnboundedSender<InspectorSessionProxy>,
+        deregister_rx: oneshot::Receiver<()>,
+        url: String,
+        wait_for_session: bool,
+    ) -> Self {
+        Self {
+            host,
+            uuid: Uuid::new_v4(),
+            thread_name: thread::current().name().map(|n| n.to_owned()),
+            new_session_tx,
+            deregister_rx,
+            url,
+            wait_for_session,
+        }
+    }
+
+    fn get_json_metadata(&self, host: &Option<String>) -> Value {
+        let host_listen = format!("{}", self.host);
+        let host = host.as_ref().unwrap_or(&host_listen);
+        json!({
+            "description": "nix-js",
+            "devtoolsFrontendUrl": self.get_frontend_url(host),
+            "faviconUrl": "https://deno.land/favicon.ico",
+            "id": self.uuid.to_string(),
+            "title": self.get_title(),
+            "type": "node",
+            "url": self.url.to_string(),
+            "webSocketDebuggerUrl": self.get_websocket_debugger_url(host),
+        })
+    }
+
+    pub fn get_websocket_debugger_url(&self, host: &str) -> String {
+        format!("ws://{}/ws/{}", host, &self.uuid)
+    }
+
+    fn get_frontend_url(&self, host: &str) -> String {
+        format!(
+            "devtools://devtools/bundled/js_app.html?ws={}/ws/{}&experiments=true&v8only=true",
+            host, &self.uuid
+        )
+    }
+
+    fn get_title(&self) -> String {
+        format!(
+            "nix-js{} [pid: {}]",
+            self.thread_name
+                .as_ref()
+                .map(|n| format!(" - {n}"))
+                .unwrap_or_default(),
+            process::id(),
+        )
+    }
+}

nix-js/src/store.rs

@@ -1,14 +1,14 @@
-#![allow(dead_code)]
+use crate::error::Result;
 
 mod config;
+mod daemon;
 mod error;
 mod validation;
 
-pub use config::{StoreConfig, StoreMode};
+pub use config::StoreConfig;
+pub use daemon::DaemonStore;
 pub use validation::validate_store_path;
 
-use crate::error::Result;
-
 pub trait Store: Send + Sync {
     fn get_store_dir(&self) -> &str;
 
@@ -37,75 +37,4 @@ pub trait Store: Send + Sync {
         content: &str,
         references: Vec<String>,
     ) -> Result<String>;
-
-    fn make_fixed_output_path(
-        &self,
-        hash_algo: &str,
-        hash: &str,
-        hash_mode: &str,
-        name: &str,
-    ) -> Result<String>;
 }
-
-pub enum StoreBackend {
-    Simulated(SimulatedStore),
-    #[cfg(feature = "daemon")]
-    Daemon(Box<DaemonStore>),
-}
-
-impl StoreBackend {
-    pub fn new(config: StoreConfig) -> Result<Self> {
-        match config.mode {
-            #[cfg(feature = "daemon")]
-            StoreMode::Daemon => {
-                let daemon = Box::new(DaemonStore::connect(&config.daemon_socket)?);
-                Ok(StoreBackend::Daemon(daemon))
-            }
-            #[cfg(not(feature = "daemon"))]
-            StoreMode::Daemon => {
-                tracing::warn!(
-                    "Daemon mode not available (nix-js not compiled with 'daemon' feature), falling back to simulated store"
-                );
-                let simulated = SimulatedStore::new()?;
-                Ok(StoreBackend::Simulated(simulated))
-            }
-            StoreMode::Simulated => {
-                let simulated = SimulatedStore::new()?;
-                Ok(StoreBackend::Simulated(simulated))
-            }
-            #[cfg(feature = "daemon")]
-            StoreMode::Auto => match DaemonStore::connect(&config.daemon_socket) {
-                Ok(daemon) => {
-                    tracing::debug!("Using nix-daemon at {}", config.daemon_socket.display());
-                    Ok(StoreBackend::Daemon(Box::new(daemon)))
-                }
-                Err(e) => {
-                    tracing::warn!("Daemon unavailable ({}), using simulated store", e);
-                    let simulated = SimulatedStore::new()?;
-                    Ok(StoreBackend::Simulated(simulated))
-                }
-            },
-            #[cfg(not(feature = "daemon"))]
-            StoreMode::Auto => {
-                let simulated = SimulatedStore::new()?;
-                Ok(StoreBackend::Simulated(simulated))
-            }
-        }
-    }
-
-    pub fn as_store(&self) -> &dyn Store {
-        match self {
-            StoreBackend::Simulated(s) => s,
-            #[cfg(feature = "daemon")]
-            StoreBackend::Daemon(d) => d.as_ref(),
-        }
-    }
-}
-
-mod simulated;
-pub use simulated::SimulatedStore;
-
-#[cfg(feature = "daemon")]
-mod daemon;
-#[cfg(feature = "daemon")]
-pub use daemon::DaemonStore;

nix-js/src/store/config.rs

@@ -1,42 +1,17 @@
 use std::path::PathBuf;
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum StoreMode {
-    Daemon,
-    Simulated,
-    Auto,
-}
-
 #[derive(Debug, Clone)]
 pub struct StoreConfig {
-    pub mode: StoreMode,
     pub daemon_socket: PathBuf,
 }
 
 impl StoreConfig {
     pub fn from_env() -> Self {
-        let mode = match std::env::var("NIX_JS_STORE_MODE")
-            .as_deref()
-            .map(|s| s.to_lowercase())
-            .as_deref()
-        {
-            Ok("daemon") => StoreMode::Daemon,
-            Ok("simulated") => StoreMode::Simulated,
-            Ok("auto") | Err(_) => StoreMode::Auto,
-            Ok(other) => {
-                tracing::warn!("Invalid NIX_JS_STORE_MODE '{}', using 'auto'", other);
-                StoreMode::Auto
-            }
-        };
-
         let daemon_socket = std::env::var("NIX_DAEMON_SOCKET")
             .map(PathBuf::from)
             .unwrap_or_else(|_| PathBuf::from("/nix/var/nix/daemon-socket/socket"));
 
-        Self {
-            mode,
-            daemon_socket,
-        }
+        Self { daemon_socket }
     }
 }
 

nix-js/src/store/daemon.rs

@@ -1,5 +1,3 @@
-#![allow(dead_code)]
-
 use std::io::{Error as IoError, ErrorKind as IoErrorKind, Result as IoResult};
 use std::path::Path;
 
@@ -9,13 +7,14 @@ use nix_compat::store_path::StorePath;
 use nix_compat::wire::ProtocolVersion;
 use nix_compat::wire::de::{NixRead, NixReader};
 use nix_compat::wire::ser::{NixSerialize, NixWrite, NixWriter, NixWriterBuilder};
+use num_enum::{IntoPrimitive, TryFromPrimitive};
+use thiserror::Error;
 use tokio::io::{AsyncReadExt, AsyncWriteExt, ReadHalf, WriteHalf, split};
 use tokio::net::UnixStream;
 use tokio::sync::Mutex;
 
-use crate::error::{Error, Result};
-
 use super::Store;
+use crate::error::{Error, Result};
 
 pub struct DaemonStore {
     runtime: tokio::runtime::Runtime,
@@ -88,11 +87,12 @@ impl Store for DaemonStore {
         recursive: bool,
         references: Vec<String>,
     ) -> Result<String> {
+        use std::fs;
+
         use nix_compat::nix_daemon::types::AddToStoreNarRequest;
         use nix_compat::nixhash::{CAHash, NixHash};
         use nix_compat::store_path::{StorePath, build_ca_path};
         use sha2::{Digest, Sha256};
-        use std::fs;
         use tempfile::NamedTempFile;
 
         let temp_file = NamedTempFile::new()
@@ -238,11 +238,12 @@ impl Store for DaemonStore {
         content: &str,
         references: Vec<String>,
     ) -> Result<String> {
+        use std::fs;
+
         use nix_compat::nix_daemon::types::AddToStoreNarRequest;
         use nix_compat::nixhash::CAHash;
         use nix_compat::store_path::{StorePath, build_text_path};
         use sha2::{Digest, Sha256};
-        use std::fs;
         use tempfile::NamedTempFile;
 
         let temp_file = NamedTempFile::new()
@@ -305,51 +306,6 @@ impl Store for DaemonStore {
 
         Ok(store_path_str)
     }
-
-    fn make_fixed_output_path(
-        &self,
-        hash_algo: &str,
-        hash: &str,
-        hash_mode: &str,
-        name: &str,
-    ) -> Result<String> {
-        use nix_compat::nixhash::{CAHash, NixHash};
-        use nix_compat::store_path::build_ca_path;
-
-        let nix_hash = match hash_algo {
-            "sha256" => {
-                let hash_bytes = hex::decode(hash)
-                    .map_err(|e| Error::internal(format!("Invalid hash hex: {}", e)))?;
-                if hash_bytes.len() != 32 {
-                    return Err(Error::internal(format!(
-                        "Invalid sha256 hash length: expected 32, got {}",
-                        hash_bytes.len()
-                    )));
-                }
-                let mut arr = [0u8; 32];
-                arr.copy_from_slice(&hash_bytes);
-                NixHash::Sha256(arr)
-            }
-            _ => {
-                return Err(Error::internal(format!(
-                    "Unsupported hash algorithm: {}",
-                    hash_algo
-                )));
-            }
-        };
-
-        let ca_hash = if hash_mode == "r" {
-            CAHash::Nar(nix_hash)
-        } else {
-            CAHash::Flat(nix_hash)
-        };
-
-        let store_path: nix_compat::store_path::StorePath<String> =
-            build_ca_path(name, &ca_hash, Vec::<String>::new(), false)
-                .map_err(|e| Error::internal(format!("Failed to build store path: {}", e)))?;
-
-        Ok(store_path.to_absolute_path())
-    }
 }
 
 const PROTOCOL_VERSION: ProtocolVersion = ProtocolVersion::from_parts(1, 37);
@@ -472,6 +428,7 @@ pub struct NixDaemonClient {
     protocol_version: ProtocolVersion,
     reader: NixReader<ReadHalf<UnixStream>>,
     writer: NixWriter<WriteHalf<UnixStream>>,
+    _marker: std::marker::PhantomData<std::cell::Cell<()>>,
 }
 
 impl NixDaemonClient {
@@ -503,26 +460,10 @@ impl NixDaemonClient {
             protocol_version,
             reader,
             writer,
+            _marker: Default::default(),
         })
     }
 
-    /// Execute an operation that returns a typed result
-    ///
-    /// This is the main method for implementing protocol operations:
-    /// 1. Send operation code
-    /// 2. Send operation parameters
-    /// 3. Receive response or error
-    async fn execute<T>(&mut self, operation: Operation) -> IoResult<T>
-    where
-        T: nix_compat::wire::de::NixDeserialize,
-    {
-        // Send operation
-        self.writer.write_value(&operation).await?;
-        self.writer.flush().await?;
-
-        self.read_response().await
-    }
-
     /// Execute an operation with a single parameter
     async fn execute_with<P, T>(&mut self, operation: Operation, param: &P) -> IoResult<T>
     where
@@ -542,7 +483,7 @@ impl NixDaemonClient {
     ///
     /// The daemon sends either:
     /// - STDERR_LAST followed by the result
-    /// - STDERR_ERROR followed by an error message
+    /// - STDERR_ERROR followed by a structured error
     async fn read_response<T>(&mut self) -> IoResult<T>
     where
         T: nix_compat::wire::de::NixDeserialize,
@@ -551,23 +492,47 @@ impl NixDaemonClient {
             let msg = self.reader.read_number().await?;
 
             if msg == STDERR_LAST {
-                // Success, read the actual response
                 let result: T = self.reader.read_value().await?;
                 return Ok(result);
             } else if msg == STDERR_ERROR {
-                // IoError, read error message
-                // The error is sent as a NixIoError struct, but we just read the message
-                let error_msg: String = self.reader.read_value().await?;
+                let error_msg = self.read_daemon_error().await?;
                 return Err(IoError::other(error_msg));
             } else {
-                // Other STDERR_* codes (logging, etc.) - for now, we ignore them
-                // Read and discard the associated data
                 let _data: String = self.reader.read_value().await?;
                 continue;
             }
         }
     }
 
+    async fn read_daemon_error(&mut self) -> IoResult<NixDaemonError> {
+        let type_marker: String = self.reader.read_value().await?;
+        assert_eq!(type_marker, "Error");
+
+        let level = NixDaemonErrorLevel::try_from_primitive(
+            self.reader
+                .read_number()
+                .await?
+                .try_into()
+                .map_err(|_| IoError::other("invalid nix-daemon error level"))?,
+        )
+        .map_err(|_| IoError::other("invalid nix-daemon error level"))?;
+        // removed
+        let _name: String = self.reader.read_value().await?;
+        let msg: String = self.reader.read_value().await?;
+        let have_pos: u64 = self.reader.read_number().await?;
+        assert_eq!(have_pos, 0);
+
+        let nr_traces: u64 = self.reader.read_number().await?;
+        let mut traces = Vec::new();
+        for _ in 0..nr_traces {
+            let _trace_pos: u64 = self.reader.read_number().await?;
+            let trace_hint: String = self.reader.read_value().await?;
+            traces.push(trace_hint);
+        }
+
+        Ok(NixDaemonError { level, msg, traces })
+    }
+
     /// Check if a path is valid in the store
     pub async fn is_valid_path(&mut self, path: &str) -> IoResult<bool> {
         let store_path = StorePath::<String>::from_absolute_path(path.as_bytes())
@@ -577,23 +542,20 @@ impl NixDaemonClient {
     }
 
     /// Query information about a store path
+    #[allow(dead_code)]
     pub async fn query_path_info(&mut self, path: &str) -> IoResult<Option<UnkeyedValidPathInfo>> {
         let store_path = StorePath::<String>::from_absolute_path(path.as_bytes())
             .map_err(|e| IoError::new(IoErrorKind::InvalidInput, e.to_string()))?;
 
-        // QueryPathInfo returns Option<UnkeyedValidPathInfo> which is serialized
-        // as a bool followed by the value if true
         self.writer.write_value(&Operation::QueryPathInfo).await?;
         self.writer.write_value(&store_path).await?;
         self.writer.flush().await?;
 
-        // Read response - it's serialized as bool + optional value
         loop {
             let msg = self.reader.read_number().await?;
             if msg == STDERR_LAST {
                 let has_value: bool = self.reader.read_value().await?;
                 if has_value {
-                    // Manually deserialize UnkeyedValidPathInfo
                     use nix_compat::narinfo::Signature;
                     use nix_compat::nixhash::CAHash;
 
@@ -621,7 +583,7 @@ impl NixDaemonClient {
                     return Ok(None);
                 }
             } else if msg == STDERR_ERROR {
-                let error_msg: String = self.reader.read_value().await?;
+                let error_msg = self.read_daemon_error().await?;
                 return Err(IoError::other(error_msg));
             } else {
                 let _data: String = self.reader.read_value().await?;
@@ -635,18 +597,16 @@ impl NixDaemonClient {
         let store_path = StorePath::<String>::from_absolute_path(path.as_bytes())
             .map_err(|e| IoError::new(IoErrorKind::InvalidInput, e.to_string()))?;
 
-        // EnsurePath returns void (no value)
         self.writer.write_value(&Operation::EnsurePath).await?;
         self.writer.write_value(&store_path).await?;
         self.writer.flush().await?;
 
-        // Read response - expect STDERR_LAST with no value
         loop {
             let msg = self.reader.read_number().await?;
             if msg == STDERR_LAST {
                 return Ok(());
             } else if msg == STDERR_ERROR {
-                let error_msg: String = self.reader.read_value().await?;
+                let error_msg = self.read_daemon_error().await?;
                 return Err(IoError::other(error_msg));
             } else {
                 let _data: String = self.reader.read_value().await?;
@@ -656,6 +616,7 @@ impl NixDaemonClient {
     }
 
     /// Query which paths are valid
+    #[allow(dead_code)]
     pub async fn query_valid_paths(&mut self, paths: Vec<String>) -> IoResult<Vec<String>> {
         let store_paths: IoResult<Vec<StorePath<String>>> = paths
             .iter()
@@ -729,7 +690,7 @@ impl NixDaemonClient {
             if msg == STDERR_LAST {
                 return Ok(());
             } else if msg == STDERR_ERROR {
-                let error_msg: String = self.reader.read_value().await?;
+                let error_msg = self.read_daemon_error().await?;
                 return Err(IoError::other(error_msg));
             } else {
                 let _data: String = self.reader.read_value().await?;
@@ -760,6 +721,7 @@ impl NixDaemonConnection {
     }
 
     /// Query information about a store path
+    #[allow(dead_code)]
     pub async fn query_path_info(&self, path: &str) -> IoResult<Option<UnkeyedValidPathInfo>> {
         let mut client = self.client.lock().await;
         client.query_path_info(path).await
@@ -772,6 +734,7 @@ impl NixDaemonConnection {
     }
 
     /// Query which paths are valid
+    #[allow(dead_code)]
     pub async fn query_valid_paths(&self, paths: Vec<String>) -> IoResult<Vec<String>> {
         let mut client = self.client.lock().await;
         client.query_valid_paths(paths).await
@@ -787,3 +750,24 @@ impl NixDaemonConnection {
         client.add_to_store_nar(request, nar_data).await
     }
 }
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, IntoPrimitive, TryFromPrimitive)]
+#[repr(u8)]
+pub enum NixDaemonErrorLevel {
+    Error = 0,
+    Warn,
+    Notice,
+    Info,
+    Talkative,
+    Chatty,
+    Debug,
+    Vomit,
+}
+
+#[derive(Debug, Error)]
+#[error("{msg}")]
+pub struct NixDaemonError {
+    level: NixDaemonErrorLevel,
+    msg: String,
+    traces: Vec<String>,
+}

nix-js/src/store/error.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use std::fmt;
 
 #[derive(Debug)]

nix-js/src/store/simulated.rs

@@ -1,121 +0,0 @@
-use super::Store;
-use crate::error::{Error, Result};
-use crate::fetcher::cache::FetcherCache;
-use std::fs;
-use std::path::Path;
-
-pub struct SimulatedStore {
-    cache: FetcherCache,
-    store_dir: String,
-}
-
-impl SimulatedStore {
-    pub fn new() -> Result<Self> {
-        let cache = FetcherCache::new()
-            .map_err(|e| Error::internal(format!("Failed to create simulated store: {}", e)))?;
-
-        let store_dir = dirs::cache_dir()
-            .unwrap_or_else(|| std::path::PathBuf::from("/tmp"))
-            .join("nix-js")
-            .join("fetchers")
-            .join("store")
-            .to_string_lossy()
-            .to_string();
-
-        Ok(Self { cache, store_dir })
-    }
-}
-
-impl Store for SimulatedStore {
-    fn get_store_dir(&self) -> &str {
-        &self.store_dir
-    }
-
-    fn is_valid_path(&self, path: &str) -> Result<bool> {
-        Ok(Path::new(path).exists())
-    }
-
-    fn ensure_path(&self, path: &str) -> Result<()> {
-        if !Path::new(path).exists() {
-            return Err(Error::eval_error(
-                format!(
-                    "builtins.storePath: path '{}' does not exist in the simulated store",
-                    path
-                ),
-                None,
-            ));
-        }
-        Ok(())
-    }
-
-    fn add_to_store(
-        &self,
-        name: &str,
-        content: &[u8],
-        _recursive: bool,
-        _references: Vec<String>,
-    ) -> Result<String> {
-        let hash = crate::nix_hash::sha256_hex(&String::from_utf8_lossy(content));
-
-        let store_path = self.cache.make_store_path(&hash, name);
-
-        if !store_path.exists() {
-            fs::create_dir_all(store_path.parent().unwrap_or(&store_path))
-                .map_err(|e| Error::internal(format!("Failed to create store directory: {}", e)))?;
-
-            fs::write(&store_path, content)
-                .map_err(|e| Error::internal(format!("Failed to write to store: {}", e)))?;
-        }
-
-        Ok(store_path.to_string_lossy().to_string())
-    }
-
-    fn add_to_store_from_path(
-        &self,
-        name: &str,
-        source_path: &Path,
-        _references: Vec<String>,
-    ) -> Result<String> {
-        use crate::fetcher::cache::copy_dir_recursive;
-
-        let nar_hash = crate::nar::compute_nar_hash(source_path)
-            .map_err(|e| Error::internal(format!("Failed to compute NAR hash: {}", e)))?;
-
-        let store_path = self.cache.make_store_path(&nar_hash, name);
-
-        if !store_path.exists() {
-            fs::create_dir_all(&store_path)
-                .map_err(|e| Error::internal(format!("Failed to create store directory: {}", e)))?;
-
-            if source_path.is_dir() {
-                copy_dir_recursive(source_path, &store_path)
-                    .map_err(|e| Error::internal(format!("Failed to copy to store: {}", e)))?;
-            } else {
-                fs::copy(source_path, &store_path)
-                    .map_err(|e| Error::internal(format!("Failed to copy to store: {}", e)))?;
-            }
-        }
-
-        Ok(store_path.to_string_lossy().to_string())
-    }
-
-    fn add_text_to_store(
-        &self,
-        name: &str,
-        content: &str,
-        references: Vec<String>,
-    ) -> Result<String> {
-        self.add_to_store(name, content.as_bytes(), false, references)
-    }
-
-    fn make_fixed_output_path(
-        &self,
-        _hash_algo: &str,
-        hash: &str,
-        _hash_mode: &str,
-        name: &str,
-    ) -> Result<String> {
-        let store_path = self.cache.make_store_path(hash, name);
-        Ok(store_path.to_string_lossy().to_string())
-    }
-}

nix-js/src/store/validation.rs

@@ -81,7 +81,7 @@ pub fn validate_store_path(store_dir: &str, path: &str) -> Result<()> {
 mod tests {
     use super::*;
 
-    #[test]
+    #[test_log::test]
     fn test_valid_store_paths() {
         let store_dir = "/nix/store";
         let valid_paths = vec![
@@ -100,7 +100,7 @@ mod tests {
         }
     }
 
-    #[test]
+    #[test_log::test]
     fn test_invalid_store_paths() {
         let store_dir = "/nix/store";
         let invalid_paths = vec![

nix-js/src/string_context.rs

@@ -0,0 +1,209 @@
+use std::collections::{BTreeMap, BTreeSet, VecDeque};
+
+pub enum StringContextElem {
+    Opaque { path: String },
+    DrvDeep { drv_path: String },
+    Built { drv_path: String, output: String },
+}
+
+impl StringContextElem {
+    pub fn decode(encoded: &str) -> Self {
+        if let Some(drv_path) = encoded.strip_prefix('=') {
+            StringContextElem::DrvDeep {
+                drv_path: drv_path.to_string(),
+            }
+        } else if let Some(rest) = encoded.strip_prefix('!') {
+            if let Some(second_bang) = rest.find('!') {
+                let output = rest[..second_bang].to_string();
+                let drv_path = rest[second_bang + 1..].to_string();
+                StringContextElem::Built { drv_path, output }
+            } else {
+                StringContextElem::Opaque {
+                    path: encoded.to_string(),
+                }
+            }
+        } else {
+            StringContextElem::Opaque {
+                path: encoded.to_string(),
+            }
+        }
+    }
+}
+
+pub type InputDrvs = BTreeMap<String, BTreeSet<String>>;
+pub type Srcs = BTreeSet<String>;
+pub fn extract_input_drvs_and_srcs(context: &[String]) -> Result<(InputDrvs, Srcs), String> {
+    let mut input_drvs: BTreeMap<String, BTreeSet<String>> = BTreeMap::new();
+    let mut input_srcs: BTreeSet<String> = BTreeSet::new();
+
+    for encoded in context {
+        match StringContextElem::decode(encoded) {
+            StringContextElem::Opaque { path } => {
+                input_srcs.insert(path);
+            }
+            StringContextElem::DrvDeep { drv_path } => {
+                compute_fs_closure(&drv_path, &mut input_drvs, &mut input_srcs)?;
+            }
+            StringContextElem::Built { drv_path, output } => {
+                input_drvs.entry(drv_path).or_default().insert(output);
+            }
+        }
+    }
+
+    Ok((input_drvs, input_srcs))
+}
+
+fn compute_fs_closure(
+    drv_path: &str,
+    input_drvs: &mut BTreeMap<String, BTreeSet<String>>,
+    input_srcs: &mut BTreeSet<String>,
+) -> Result<(), String> {
+    let mut queue: VecDeque<String> = VecDeque::new();
+    let mut visited: BTreeSet<String> = BTreeSet::new();
+
+    queue.push_back(drv_path.to_string());
+
+    while let Some(current_path) = queue.pop_front() {
+        if visited.contains(&current_path) {
+            continue;
+        }
+        visited.insert(current_path.clone());
+        input_srcs.insert(current_path.clone());
+
+        if !current_path.ends_with(".drv") {
+            continue;
+        }
+
+        let content = std::fs::read_to_string(&current_path)
+            .map_err(|e| format!("failed to read derivation {}: {}", current_path, e))?;
+
+        let inputs = parse_derivation_inputs(&content)
+            .ok_or_else(|| format!("failed to parse derivation {}", current_path))?;
+
+        for src in inputs.input_srcs {
+            input_srcs.insert(src.clone());
+            if !visited.contains(&src) {
+                queue.push_back(src);
+            }
+        }
+
+        for (dep_drv, outputs) in inputs.input_drvs {
+            input_srcs.insert(dep_drv.clone());
+            let entry = input_drvs.entry(dep_drv.clone()).or_default();
+            for output in outputs {
+                entry.insert(output);
+            }
+            if !visited.contains(&dep_drv) {
+                queue.push_back(dep_drv);
+            }
+        }
+    }
+
+    Ok(())
+}
+
+struct DerivationInputs {
+    input_drvs: Vec<(String, Vec<String>)>,
+    input_srcs: Vec<String>,
+}
+
+fn parse_derivation_inputs(aterm: &str) -> Option<DerivationInputs> {
+    let aterm = aterm.strip_prefix("Derive([")?;
+
+    let mut bracket_count: i32 = 1;
+    let mut pos = 0;
+    let bytes = aterm.as_bytes();
+    while pos < bytes.len() && bracket_count > 0 {
+        match bytes[pos] {
+            b'[' => bracket_count += 1,
+            b']' => bracket_count -= 1,
+            _ => {}
+        }
+        pos += 1;
+    }
+    if bracket_count != 0 {
+        return None;
+    }
+
+    let rest = &aterm[pos..];
+    let rest = rest.strip_prefix(",[")?;
+
+    let mut input_drvs = Vec::new();
+    let mut bracket_count: i32 = 1;
+    let mut start = 0;
+    pos = 0;
+    let bytes = rest.as_bytes();
+
+    while pos < bytes.len() && bracket_count > 0 {
+        match bytes[pos] {
+            b'[' => bracket_count += 1,
+            b']' => bracket_count -= 1,
+            b'(' if bracket_count == 1 => {
+                start = pos;
+            }
+            b')' if bracket_count == 1 => {
+                let entry = &rest[start + 1..pos];
+                if let Some((drv_path, outputs)) = parse_input_drv_entry(entry) {
+                    input_drvs.push((drv_path, outputs));
+                }
+            }
+            _ => {}
+        }
+        pos += 1;
+    }
+
+    let rest = &rest[pos..];
+    let rest = rest.strip_prefix(",[")?;
+
+    let mut input_srcs = Vec::new();
+    bracket_count = 1;
+    pos = 0;
+    let bytes = rest.as_bytes();
+
+    while pos < bytes.len() && bracket_count > 0 {
+        match bytes[pos] {
+            b'[' => bracket_count += 1,
+            b']' => bracket_count -= 1,
+            b'"' if bracket_count == 1 => {
+                pos += 1;
+                let src_start = pos;
+                while pos < bytes.len() && bytes[pos] != b'"' {
+                    if bytes[pos] == b'\\' && pos + 1 < bytes.len() {
+                        pos += 2;
+                    } else {
+                        pos += 1;
+                    }
+                }
+                let src = std::str::from_utf8(&bytes[src_start..pos]).ok()?;
+                input_srcs.push(src.to_string());
+            }
+            _ => {}
+        }
+        pos += 1;
+    }
+
+    Some(DerivationInputs {
+        input_drvs,
+        input_srcs,
+    })
+}
+
+fn parse_input_drv_entry(entry: &str) -> Option<(String, Vec<String>)> {
+    let entry = entry.strip_prefix('"')?;
+    let quote_end = entry.find('"')?;
+    let drv_path = entry[..quote_end].to_string();
+
+    let rest = &entry[quote_end + 1..];
+    let rest = rest.strip_prefix(",[")?;
+    let rest = rest.strip_suffix(']')?;
+
+    let mut outputs = Vec::new();
+    for part in rest.split(',') {
+        let part = part.trim();
+        if let Some(name) = part.strip_prefix('"').and_then(|s| s.strip_suffix('"')) {
+            outputs.push(name.to_string());
+        }
+    }
+
+    Some((drv_path, outputs))
+}

nix-js/src/value.rs

@@ -1,94 +1,85 @@
 use core::fmt::{Debug, Display, Formatter, Result as FmtResult};
 use core::hash::Hash;
 use core::ops::Deref;
-
 use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::ops::DerefMut;
-use std::sync::LazyLock;
 
 use derive_more::{Constructor, IsVariant, Unwrap};
-use regex::Regex;
 
 /// Represents a Nix symbol, which is used as a key in attribute sets.
 #[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Constructor)]
-pub struct Symbol(String);
+pub struct Symbol<'a>(Cow<'a, str>);
 
-impl<T: Into<String>> From<T> for Symbol {
-    fn from(value: T) -> Self {
-        Symbol(value.into())
+pub type StaticSymbol = Symbol<'static>;
+
+impl From<String> for Symbol<'_> {
+    fn from(value: String) -> Self {
+        Symbol(Cow::Owned(value))
+    }
+}
+
+impl<'a> From<&'a str> for Symbol<'a> {
+    fn from(value: &'a str) -> Self {
+        Symbol(Cow::Borrowed(value))
     }
 }
 
 /// Formats a string slice as a Nix symbol, quoting it if necessary.
 pub fn format_symbol<'a>(sym: impl Into<Cow<'a, str>>) -> Cow<'a, str> {
     let sym = sym.into();
-    if REGEX.is_match(&sym) {
+    if Symbol::NORMAL_REGEX.test(&sym) {
         sym
     } else {
-        Cow::Owned(format!(r#""{sym}""#))
+        Cow::Owned(escape_quote_string(&sym))
     }
 }
 
-impl Display for Symbol {
+impl Display for Symbol<'_> {
     fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
         if self.normal() {
             write!(f, "{}", self.0)
         } else {
-            write!(f, r#""{}""#, self.0)
+            write!(f, "{}", escape_quote_string(&self.0))
         }
     }
 }
 
-static REGEX: LazyLock<Regex> = LazyLock::new(|| {
-    Regex::new(r"^[a-zA-Z_][a-zA-Z0-9_'-]*$").expect("hardcoded regex is always valid")
-});
-impl Symbol {
+impl Symbol<'_> {
+    const NORMAL_REGEX: ere::Regex<1> = ere::compile_regex!("^[a-zA-Z_][a-zA-Z0-9_'-]*$");
     /// Checks if the symbol is a "normal" identifier that doesn't require quotes.
     fn normal(&self) -> bool {
-        REGEX.is_match(self)
+        Self::NORMAL_REGEX.test(self)
     }
 }
 
-impl Deref for Symbol {
+impl Deref for Symbol<'_> {
     type Target = str;
     fn deref(&self) -> &Self::Target {
         &self.0
     }
 }
 
-impl Symbol {
-    /// Consumes the `Symbol`, returning its inner `String`.
-    pub fn into_inner(self) -> String {
-        self.0
-    }
-
-    /// Returns a reference to the inner `String`.
-    pub fn as_inner(&self) -> &String {
-        &self.0
-    }
-}
-
 /// Represents a Nix attribute set, which is a map from symbols to values.
 #[derive(Constructor, Default, Clone, PartialEq)]
 pub struct AttrSet {
-    data: BTreeMap<Symbol, Value>,
+    data: BTreeMap<StaticSymbol, Value>,
 }
 
 impl AttrSet {
     /// Gets a value by key (string or Symbol).
-    pub fn get(&self, key: impl Into<Symbol>) -> Option<&Value> {
+    pub fn get<'a, 'sym: 'a>(&'a self, key: impl Into<Symbol<'sym>>) -> Option<&'a Value> {
         self.data.get(&key.into())
     }
 
     /// Checks if a key exists in the attribute set.
-    pub fn contains_key(&self, key: impl Into<Symbol>) -> bool {
+    pub fn contains_key<'a, 'sym: 'a>(&'a self, key: impl Into<Symbol<'sym>>) -> bool {
         self.data.contains_key(&key.into())
     }
 }
 
 impl Deref for AttrSet {
-    type Target = BTreeMap<Symbol, Value>;
+    type Target = BTreeMap<StaticSymbol, Value>;
     fn deref(&self) -> &Self::Target {
         &self.data
     }
@@ -117,9 +108,46 @@ impl Debug for AttrSet {
 
 impl Display for AttrSet {
     fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
+        use Value::*;
+        if self.data.len() > 1 {
+            writeln!(f, "{{")?;
+            for (k, v) in self.data.iter() {
+                write!(f, "  {k} = ")?;
+                match v {
+                    List(_) => writeln!(f, "[ ... ];")?,
+                    AttrSet(_) => writeln!(f, "{{ ... }};")?,
+                    v => writeln!(f, "{v};")?,
+                }
+            }
+            write!(f, "}}")
+        } else {
             write!(f, "{{")?;
             for (k, v) in self.data.iter() {
-            write!(f, " {k} = {v};")?;
+                write!(f, " {k} = ")?;
+                match v {
+                    List(_) => write!(f, "[ ... ];")?,
+                    AttrSet(_) => write!(f, "{{ ... }};")?,
+                    v => write!(f, "{v};")?,
+                }
+            }
+            write!(f, " }}")
+        }
+    }
+}
+
+impl AttrSet {
+    pub fn display_compat(&self) -> AttrSetCompatDisplay<'_> {
+        AttrSetCompatDisplay(self)
+    }
+}
+
+pub struct AttrSetCompatDisplay<'a>(&'a AttrSet);
+
+impl Display for AttrSetCompatDisplay<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
+        write!(f, "{{")?;
+        for (k, v) in self.0.data.iter() {
+            write!(f, " {k} = {};", v.display_compat())?;
         }
         write!(f, " }}")
     }
@@ -145,9 +173,44 @@ impl DerefMut for List {
 
 impl Display for List {
     fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
+        use Value::*;
+        if self.data.len() > 1 {
+            writeln!(f, "[")?;
+            for v in self.data.iter() {
+                match v {
+                    List(_) => writeln!(f, "  [ ... ]")?,
+                    AttrSet(_) => writeln!(f, "  {{ ... }}")?,
+                    v => writeln!(f, "  {v}")?,
+                }
+            }
+            write!(f, "]")
+        } else {
             write!(f, "[ ")?;
             for v in self.data.iter() {
-            write!(f, "{v} ")?;
+                match v {
+                    List(_) => write!(f, "[ ... ] ")?,
+                    AttrSet(_) => write!(f, "{{ ... }} ")?,
+                    v => write!(f, "{v} ")?,
+                }
+            }
+            write!(f, "]")
+        }
+    }
+}
+
+impl List {
+    pub fn display_compat(&self) -> ListCompatDisplay<'_> {
+        ListCompatDisplay(self)
+    }
+}
+
+pub struct ListCompatDisplay<'a>(&'a List);
+
+impl Display for ListCompatDisplay<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
+        write!(f, "[ ")?;
+        for v in self.0.data.iter() {
+            write!(f, "{} ", v.display_compat())?;
         }
         write!(f, "]")
     }
@@ -185,28 +248,88 @@ pub enum Value {
     Repeated,
 }
 
+fn escape_quote_string(s: &str) -> String {
+    let mut ret = String::with_capacity(s.len() + 2);
+    ret.push('"');
+    let mut iter = s.chars().peekable();
+    while let Some(c) = iter.next() {
+        match c {
+            '\\' => ret.push_str("\\\\"),
+            '"' => ret.push_str("\\\""),
+            '\n' => ret.push_str("\\n"),
+            '\r' => ret.push_str("\\r"),
+            '\t' => ret.push_str("\\t"),
+            '$' if iter.peek() == Some(&'{') => ret.push_str("\\$"),
+            c => ret.push(c),
+        }
+    }
+    ret.push('"');
+    ret
+}
+
+/// Format a float matching C's `printf("%g", x)` with default precision 6.
+fn fmt_nix_float(f: &mut Formatter<'_>, x: f64) -> FmtResult {
+    if !x.is_finite() {
+        return write!(f, "{x}");
+    }
+    if x == 0.0 {
+        return if x.is_sign_negative() {
+            write!(f, "-0")
+        } else {
+            write!(f, "0")
+        };
+    }
+
+    let precision: i32 = 6;
+    let exp = x.abs().log10().floor() as i32;
+
+    let formatted = if exp >= -4 && exp < precision {
+        let decimal_places = (precision - 1 - exp) as usize;
+        format!("{x:.decimal_places$}")
+    } else {
+        let sig_digits = (precision - 1) as usize;
+        let s = format!("{x:.sig_digits$e}");
+        let (mantissa, exp_part) = s
+            .split_once('e')
+            .expect("scientific notation must contain 'e'");
+        let (sign, digits) = if let Some(d) = exp_part.strip_prefix('-') {
+            ("-", d)
+        } else if let Some(d) = exp_part.strip_prefix('+') {
+            ("+", d)
+        } else {
+            ("+", exp_part)
+        };
+        if digits.len() < 2 {
+            format!("{mantissa}e{sign}0{digits}")
+        } else {
+            format!("{mantissa}e{sign}{digits}")
+        }
+    };
+
+    if formatted.contains('.') {
+        if let Some(e_pos) = formatted.find('e') {
+            let trimmed = formatted[..e_pos]
+                .trim_end_matches('0')
+                .trim_end_matches('.');
+            write!(f, "{}{}", trimmed, &formatted[e_pos..])
+        } else {
+            let trimmed = formatted.trim_end_matches('0').trim_end_matches('.');
+            write!(f, "{trimmed}")
+        }
+    } else {
+        write!(f, "{formatted}")
+    }
+}
+
 impl Display for Value {
     fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
         use Value::*;
         match self {
             &Int(x) => write!(f, "{x}"),
-            &Float(x) => write!(f, "{x}"),
+            &Float(x) => fmt_nix_float(f, x),
             &Bool(x) => write!(f, "{x}"),
             Null => write!(f, "null"),
-            String(x) => {
-                write!(f, "\"")?;
-                for c in x.chars() {
-                    match c {
-                        '\\' => write!(f, "\\\\")?,
-                        '"' => write!(f, "\\\"")?,
-                        '\n' => write!(f, "\\n")?,
-                        '\r' => write!(f, "\\r")?,
-                        '\t' => write!(f, "\\t")?,
-                        c => write!(f, "{c}")?,
-                    }
-                }
-                write!(f, "\"")
-            }
+            String(x) => write!(f, "{}", escape_quote_string(x)),
             Path(x) => write!(f, "{x}"),
             AttrSet(x) => write!(f, "{x}"),
             List(x) => write!(f, "{x}"),
@@ -218,3 +341,32 @@ impl Display for Value {
         }
     }
 }
+
+impl Value {
+    pub fn display_compat(&self) -> ValueCompatDisplay<'_> {
+        ValueCompatDisplay(self)
+    }
+}
+
+pub struct ValueCompatDisplay<'a>(&'a Value);
+
+impl Display for ValueCompatDisplay<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
+        use Value::*;
+        match self.0 {
+            &Int(x) => write!(f, "{x}"),
+            &Float(x) => fmt_nix_float(f, x),
+            &Bool(x) => write!(f, "{x}"),
+            Null => write!(f, "null"),
+            String(x) => write!(f, "{}", escape_quote_string(x)),
+            Path(x) => write!(f, "{x}"),
+            AttrSet(x) => write!(f, "{}", x.display_compat()),
+            List(x) => write!(f, "{}", x.display_compat()),
+            Thunk => write!(f, "«thunk»"),
+            Func => write!(f, "<LAMBDA>"),
+            PrimOp(_) => write!(f, "<PRIMOP>"),
+            PrimOpApp(_) => write!(f, "<PRIMOP-APP>"),
+            Repeated => write!(f, "«repeated»"),
+        }
+    }
+}

nix-js/tests/lang/eval-okay-intersectAttrs.exp

@@ -1 +0,0 @@
-[ { } { a = 1; } { a = 1; } { a = "a"; } { m = 1; } { m = "m"; } { n = 1; } { n = "n"; } { n = 1; p = 2; } { n = "n"; p = "p"; } { n = 1; p = 2; } { n = "n"; p = "p"; } { a = "a"; b = "b"; c = "c"; d = "d"; e = "e"; f = "f"; g = "g"; h = "h"; i = "i"; j = "j"; k = "k"; l = "l"; m = "m"; n = "n"; o = "o"; p = "p"; q = "q"; r = "r"; s = "s"; t = "t"; u = "u"; v = "v"; w = "w"; x = "x"; y = "y"; z = "z"; } true ]

nix-js/tests/lang/eval-okay-print.exp

@@ -1 +0,0 @@
-[ null <PRIMOP> <PRIMOP-APP> <LAMBDA> [ [ «repeated» ] ] ]

nix-js/tests/tests/basic_eval.rs

@@ -1,36 +1,33 @@
-mod utils;
-
 use nix_js::value::Value;
-use utils::eval;
 
-use crate::utils::eval_result;
+use crate::utils::{eval, eval_result};
 
-#[test]
+#[test_log::test]
 fn arithmetic() {
     assert_eq!(eval("1 + 1"), Value::Int(2));
 }
 
-#[test]
+#[test_log::test]
 fn simple_function_application() {
     assert_eq!(eval("(x: x) 1"), Value::Int(1));
 }
 
-#[test]
+#[test_log::test]
 fn curried_function() {
     assert_eq!(eval("(x: y: x - y) 2 1"), Value::Int(1));
 }
 
-#[test]
+#[test_log::test]
 fn rec_attrset() {
     assert_eq!(eval("rec { b = a; a = 1; }.b"), Value::Int(1));
 }
 
-#[test]
+#[test_log::test]
 fn let_binding() {
     assert_eq!(eval("let b = a; a = 1; in b"), Value::Int(1));
 }
 
-#[test]
+#[test_log::test]
 fn fibonacci() {
     assert_eq!(
         eval(
@@ -40,7 +37,7 @@ fn fibonacci() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn fixed_point_combinator() {
     assert_eq!(
         eval("((f: let x = f x; in x)(self: { x = 1; y = self.x + 1; })).y"),
@@ -48,17 +45,17 @@ fn fixed_point_combinator() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn conditional_true() {
     assert_eq!(eval("if true then 1 else 0"), Value::Int(1));
 }
 
-#[test]
+#[test_log::test]
 fn conditional_false() {
     assert_eq!(eval("if false then 1 else 0"), Value::Int(0));
 }
 
-#[test]
+#[test_log::test]
 fn nested_let() {
     assert_eq!(
         eval("let x = 1; in let y = x + 1; z = y + 1; in z"),
@@ -66,7 +63,7 @@ fn nested_let() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn rec_inherit_fails() {
     assert!(eval_result("{ inherit x; }").is_err());
 }

nix-js/tests/tests/builtins.rs

@@ -1,33 +1,32 @@
-mod utils;
-
 use std::collections::BTreeMap;
 
 use nix_js::value::{AttrSet, List, Value};
-use utils::eval;
 
-#[test]
+use crate::utils::eval;
+
+#[test_log::test]
 fn builtins_accessible() {
     let result = eval("builtins");
     assert!(matches!(result, Value::AttrSet(_)));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_self_reference() {
     let result = eval("builtins.builtins");
     assert!(matches!(result, Value::AttrSet(_)));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_add() {
     assert_eq!(eval("builtins.add 1 2"), Value::Int(3));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_length() {
     assert_eq!(eval("builtins.length [1 2 3]"), Value::Int(3));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_map() {
     assert_eq!(
         eval("builtins.map (x: x * 2) [1 2 3]"),
@@ -35,7 +34,7 @@ fn builtins_map() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_filter() {
     assert_eq!(
         eval("builtins.filter (x: x > 1) [1 2 3]"),
@@ -43,7 +42,7 @@ fn builtins_filter() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_attrnames() {
     let result = eval("builtins.attrNames { a = 1; b = 2; }");
     assert!(matches!(result, Value::List(_)));
@@ -52,12 +51,12 @@ fn builtins_attrnames() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn builtins_head() {
     assert_eq!(eval("builtins.head [1 2 3]"), Value::Int(1));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_tail() {
     assert_eq!(
         eval("builtins.tail [1 2 3]"),
@@ -65,17 +64,17 @@ fn builtins_tail() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_in_let() {
     assert_eq!(eval("let b = builtins; in b.add 5 3"), Value::Int(8));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_in_with() {
     assert_eq!(eval("with builtins; add 10 20"), Value::Int(30));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_nested_calls() {
     assert_eq!(
         eval("builtins.add (builtins.mul 2 3) (builtins.sub 10 5)"),
@@ -83,32 +82,32 @@ fn builtins_nested_calls() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_is_list() {
     assert_eq!(eval("builtins.isList [1 2 3]"), Value::Bool(true));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_is_attrs() {
     assert_eq!(eval("builtins.isAttrs { a = 1; }"), Value::Bool(true));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_is_function() {
     assert_eq!(eval("builtins.isFunction (x: x)"), Value::Bool(true));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_is_null() {
     assert_eq!(eval("builtins.isNull null"), Value::Bool(true));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_is_bool() {
     assert_eq!(eval("builtins.isBool true"), Value::Bool(true));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_shadowing() {
     assert_eq!(
         eval("let builtins = { add = x: y: x - y; }; in builtins.add 5 3"),
@@ -116,13 +115,13 @@ fn builtins_shadowing() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_lazy_evaluation() {
     let result = eval("builtins.builtins.builtins.add 1 1");
     assert_eq!(result, Value::Int(2));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_foldl() {
     assert_eq!(
         eval("builtins.foldl' (acc: x: acc + x) 0 [1 2 3 4 5]"),
@@ -130,13 +129,13 @@ fn builtins_foldl() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_elem() {
     assert_eq!(eval("builtins.elem 2 [1 2 3]"), Value::Bool(true));
     assert_eq!(eval("builtins.elem 5 [1 2 3]"), Value::Bool(false));
 }
 
-#[test]
+#[test_log::test]
 fn builtins_concat_lists() {
     assert_eq!(
         eval("builtins.concatLists [[1 2] [3 4] [5]]"),
@@ -150,7 +149,7 @@ fn builtins_concat_lists() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_compare_versions_basic() {
     assert_eq!(
         eval("builtins.compareVersions \"1.0\" \"2.3\""),
@@ -174,7 +173,7 @@ fn builtins_compare_versions_basic() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_compare_versions_components() {
     assert_eq!(
         eval("builtins.compareVersions \"2.3.1\" \"2.3\""),
@@ -186,7 +185,7 @@ fn builtins_compare_versions_components() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_compare_versions_numeric_vs_alpha() {
     // Numeric component comes before alpha component
     assert_eq!(
@@ -199,7 +198,7 @@ fn builtins_compare_versions_numeric_vs_alpha() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_compare_versions_pre() {
     // "pre" is special: comes before everything except another "pre"
     assert_eq!(
@@ -220,7 +219,7 @@ fn builtins_compare_versions_pre() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_compare_versions_alpha() {
     // Alphabetic comparison
     assert_eq!(
@@ -233,7 +232,7 @@ fn builtins_compare_versions_alpha() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_compare_versions_symmetry() {
     // Test symmetry: compareVersions(a, b) == -compareVersions(b, a)
     assert_eq!(
@@ -246,7 +245,7 @@ fn builtins_compare_versions_symmetry() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_compare_versions_complex() {
     // Complex version strings with multiple components
     assert_eq!(
@@ -263,7 +262,7 @@ fn builtins_compare_versions_complex() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_generic_closure() {
     assert_eq!(
         eval(
@@ -279,7 +278,7 @@ fn builtins_generic_closure() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_function_args() {
     assert_eq!(
         eval("builtins.functionArgs (x: 1)"),
@@ -316,7 +315,7 @@ fn builtins_function_args() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn builtins_parse_drv_name() {
     let result = eval(r#"builtins.parseDrvName "nix-js-0.1.0pre""#).unwrap_attr_set();
     assert_eq!(result.get("name"), Some(&Value::String("nix-js".into())));

nix-js/tests/tests/builtins_store.rs

@@ -1,28 +1,9 @@
-mod utils;
-
-use std::sync::Once;
-
 use nix_js::value::Value;
-use utils::eval_result;
 
-fn init() {
-    static INIT: Once = Once::new();
-    INIT.call_once(|| {
-        #[cfg(not(feature = "daemon"))]
-        unsafe {
-            std::env::set_var("NIX_JS_STORE_MODE", "simulated")
-        };
-        #[cfg(feature = "daemon")]
-        unsafe {
-            std::env::set_var("NIX_JS_STORE_MODE", "daemon")
-        };
-    });
-}
+use crate::utils::eval_result;
 
-#[test]
+#[test_log::test]
 fn to_file_simple() {
-    init();
-
     let result =
         eval_result(r#"builtins.toFile "hello.txt" "Hello, World!""#).expect("Failed to evaluate");
 
@@ -38,10 +19,8 @@ fn to_file_simple() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn to_file_with_references() {
-    init();
-
     let result = eval_result(
         r#"
             let
@@ -63,10 +42,8 @@ fn to_file_with_references() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn to_file_invalid_name_with_slash() {
-    init();
-
     let result = eval_result(r#"builtins.toFile "foo/bar.txt" "content""#);
 
     assert!(result.is_err());
@@ -78,30 +55,24 @@ fn to_file_invalid_name_with_slash() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn to_file_invalid_name_dot() {
-    init();
-
     let result = eval_result(r#"builtins.toFile "." "content""#);
 
     assert!(result.is_err());
     assert!(result.unwrap_err().to_string().contains("invalid name"));
 }
 
-#[test]
+#[test_log::test]
 fn to_file_invalid_name_dotdot() {
-    init();
-
     let result = eval_result(r#"builtins.toFile ".." "content""#);
 
     assert!(result.is_err());
     assert!(result.unwrap_err().to_string().contains("invalid name"));
 }
 
-#[test]
+#[test_log::test]
 fn store_path_validation_not_in_store() {
-    init();
-
     let result = eval_result(r#"builtins.storePath "/tmp/foo""#);
 
     assert!(result.is_err());
@@ -113,10 +84,8 @@ fn store_path_validation_not_in_store() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn store_path_validation_malformed_hash() {
-    init();
-
     let dummy_file_result = eval_result(r#"builtins.toFile "dummy.txt" "content""#)
         .expect("Failed to create dummy file");
 
@@ -143,10 +112,8 @@ fn store_path_validation_malformed_hash() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn store_path_validation_missing_name() {
-    init();
-
     let dummy_file_result = eval_result(r#"builtins.toFile "dummy.txt" "content""#)
         .expect("Failed to create dummy file");
 
@@ -173,10 +140,8 @@ fn store_path_validation_missing_name() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn to_file_curried_application() {
-    init();
-
     let result = eval_result(
         r#"
             let
@@ -197,10 +162,8 @@ fn to_file_curried_application() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn to_file_number_conversion() {
-    init();
-
     let result = eval_result(r#"builtins.toFile "number.txt" (builtins.toString 42)"#)
         .expect("Failed to evaluate");
 
@@ -213,10 +176,8 @@ fn to_file_number_conversion() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn to_file_list_conversion() {
-    init();
-
     let result = eval_result(
         r#"builtins.toFile "list.txt" (builtins.concatStringsSep "\n" ["line1" "line2" "line3"])"#,
     )

nix-js/tests/tests/derivation.rs

@@ -1,14 +1,48 @@
-#![cfg(feature = "daemon")]
-
-mod utils;
-
 use nix_js::value::Value;
-use utils::{eval, eval_result};
 
-#[test]
+use crate::utils::{eval_deep, eval_deep_result};
+
+#[test_log::test]
+fn add_operator_preserves_derivation_context() {
+    let result = eval_deep(
+        r#"
+        let
+          dep = derivation { name = "dep"; builder = "/bin/sh"; system = "x86_64-linux"; outputs = ["out" "dev"]; };
+          getOutput = output: pkg: pkg.${output} or pkg.out or pkg;
+          user = derivation {
+            name = "user";
+            builder = "/bin/sh";
+            system = "x86_64-linux";
+            libPath = (getOutput "lib" dep) + "/lib";
+            devPath = dep.dev + "/include";
+          };
+        in user.drvPath
+        "#,
+    );
+
+    let nix_result = eval_deep(
+        r#"
+        let
+          dep = derivation { name = "dep"; builder = "/bin/sh"; system = "x86_64-linux"; outputs = ["out" "dev"]; };
+          user = derivation {
+            name = "user";
+            builder = "/bin/sh";
+            system = "x86_64-linux";
+            libPath = "${dep.out}/lib";
+            devPath = "${dep.dev}/include";
+          };
+        in user.drvPath
+        "#,
+    );
+
+    assert_eq!(result, nix_result);
+}
+
+#[test_log::test]
 fn derivation_minimal() {
-    let result =
-        eval(r#"derivation { name = "hello"; builder = "/bin/sh"; system = "x86_64-linux"; }"#);
+    let result = eval_deep(
+        r#"derivation { name = "hello"; builder = "/bin/sh"; system = "x86_64-linux"; }"#,
+    );
 
     match result {
         Value::AttrSet(attrs) => {
@@ -42,9 +76,9 @@ fn derivation_minimal() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn derivation_with_args() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "test";
             builder = "/bin/sh";
@@ -64,9 +98,9 @@ fn derivation_with_args() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn derivation_to_string() {
-    let result = eval(
+    let result = eval_deep(
         r#"toString (derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; })"#,
     );
 
@@ -76,18 +110,19 @@ fn derivation_to_string() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn derivation_missing_name() {
-    let result = eval_result(r#"derivation { builder = "/bin/sh"; system = "x86_64-linux"; }"#);
+    let result =
+        eval_deep_result(r#"derivation { builder = "/bin/sh"; system = "x86_64-linux"; }"#);
 
     assert!(result.is_err());
     let err_msg = result.unwrap_err().to_string();
     assert!(err_msg.contains("missing required attribute 'name'"));
 }
 
-#[test]
+#[test_log::test]
 fn derivation_invalid_name_with_drv_suffix() {
-    let result = eval_result(
+    let result = eval_deep_result(
         r#"derivation { name = "foo.drv"; builder = "/bin/sh"; system = "x86_64-linux"; }"#,
     );
 
@@ -96,27 +131,27 @@ fn derivation_invalid_name_with_drv_suffix() {
     assert!(err_msg.contains("cannot end with .drv"));
 }
 
-#[test]
+#[test_log::test]
 fn derivation_missing_builder() {
-    let result = eval_result(r#"derivation { name = "test"; system = "x86_64-linux"; }"#);
+    let result = eval_deep_result(r#"derivation { name = "test"; system = "x86_64-linux"; }"#);
 
     assert!(result.is_err());
     let err_msg = result.unwrap_err().to_string();
     assert!(err_msg.contains("missing required attribute 'builder'"));
 }
 
-#[test]
+#[test_log::test]
 fn derivation_missing_system() {
-    let result = eval_result(r#"derivation { name = "test"; builder = "/bin/sh"; }"#);
+    let result = eval_deep_result(r#"derivation { name = "test"; builder = "/bin/sh"; }"#);
 
     assert!(result.is_err());
     let err_msg = result.unwrap_err().to_string();
     assert!(err_msg.contains("missing required attribute 'system'"));
 }
 
-#[test]
+#[test_log::test]
 fn derivation_with_env_vars() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "test";
             builder = "/bin/sh";
@@ -135,9 +170,9 @@ fn derivation_with_env_vars() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn derivation_strict() {
-    let result = eval(
+    let result = eval_deep(
         r#"builtins.derivationStrict { name = "test"; builder = "/bin/sh"; system = "x86_64-linux"; }"#,
     );
 
@@ -152,12 +187,12 @@ fn derivation_strict() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn derivation_deterministic_paths() {
     let expr = r#"derivation { name = "hello"; builder = "/bin/sh"; system = "x86_64-linux"; }"#;
 
-    let result1 = eval(expr);
-    let result2 = eval(expr);
+    let result1 = eval_deep(expr);
+    let result2 = eval_deep(expr);
 
     match (result1, result2) {
         (Value::AttrSet(attrs1), Value::AttrSet(attrs2)) => {
@@ -168,9 +203,9 @@ fn derivation_deterministic_paths() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn derivation_escaping_in_aterm() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "test";
             builder = "/bin/sh";
@@ -188,9 +223,9 @@ fn derivation_escaping_in_aterm() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn multi_output_two_outputs() {
-    let drv = eval(
+    let drv = eval_deep(
         r#"derivation {
             name = "multi";
             builder = "/bin/sh";
@@ -231,9 +266,9 @@ fn multi_output_two_outputs() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn multi_output_three_outputs() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "three";
             builder = "/bin/sh";
@@ -279,9 +314,9 @@ fn multi_output_three_outputs() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn multi_output_backward_compat() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "compat";
             builder = "/bin/sh";
@@ -305,9 +340,9 @@ fn multi_output_backward_compat() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn multi_output_deterministic() {
-    let result1 = eval(
+    let result1 = eval_deep(
         r#"derivation {
             name = "determ";
             builder = "/bin/sh";
@@ -316,7 +351,7 @@ fn multi_output_deterministic() {
         }"#,
     );
 
-    let result2 = eval(
+    let result2 = eval_deep(
         r#"derivation {
             name = "determ";
             builder = "/bin/sh";
@@ -328,9 +363,9 @@ fn multi_output_deterministic() {
     assert_eq!(result1, result2);
 }
 
-#[test]
+#[test_log::test]
 fn fixed_output_sha256_flat() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "fixed";
             builder = "/bin/sh";
@@ -365,32 +400,24 @@ fn fixed_output_sha256_flat() {
     }
 }
 
-#[test]
-fn fixed_output_default_algo() {
-    let result = eval(
+#[test_log::test]
+fn fixed_output_missing_hashalgo() {
+    assert!(
+        eval_deep_result(
             r#"derivation {
             name = "default";
             builder = "/bin/sh";
             system = "x86_64-linux";
             outputHash = "0000000000000000000000000000000000000000000000000000000000000000";
         }"#,
+        )
+        .is_err()
     );
-
-    match result {
-        Value::AttrSet(attrs) => {
-            assert!(attrs.contains_key("outPath"));
-            // Verify it defaults to sha256 (same as explicitly specifying it)
-            if let Some(Value::String(out_path)) = attrs.get("outPath") {
-                assert!(out_path.contains("/nix/store/"));
-            }
-        }
-        _ => panic!("Expected AttrSet"),
-    }
 }
 
-#[test]
+#[test_log::test]
 fn fixed_output_recursive_mode() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "recursive";
             builder = "/bin/sh";
@@ -418,14 +445,15 @@ fn fixed_output_recursive_mode() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn fixed_output_rejects_multi_output() {
-    let result = eval_result(
+    let result = eval_deep_result(
         r#"derivation {
             name = "invalid";
             builder = "/bin/sh";
             system = "x86_64-linux";
             outputHash = "0000000000000000000000000000000000000000000000000000000000000000";
+            outputHashAlgo = "sha256";
             outputs = ["out" "dev"];
         }"#,
     );
@@ -435,9 +463,9 @@ fn fixed_output_rejects_multi_output() {
     assert!(err_msg.contains("fixed-output") && err_msg.contains("one"));
 }
 
-#[test]
+#[test_log::test]
 fn fixed_output_invalid_hash_mode() {
-    let result = eval_result(
+    let result = eval_deep_result(
         r#"derivation {
             name = "invalid";
             builder = "/bin/sh";
@@ -452,9 +480,9 @@ fn fixed_output_invalid_hash_mode() {
     assert!(err_msg.contains("outputHashMode") && err_msg.contains("invalid"));
 }
 
-#[test]
+#[test_log::test]
 fn structured_attrs_basic() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "struct";
             builder = "/bin/sh";
@@ -477,9 +505,9 @@ fn structured_attrs_basic() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn structured_attrs_nested() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "nested";
             builder = "/bin/sh";
@@ -498,9 +526,9 @@ fn structured_attrs_nested() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn structured_attrs_rejects_functions() {
-    let result = eval_result(
+    let result = eval_deep_result(
         r#"derivation {
             name = "invalid";
             builder = "/bin/sh";
@@ -512,12 +540,12 @@ fn structured_attrs_rejects_functions() {
 
     assert!(result.is_err());
     let err_msg = result.unwrap_err().to_string();
-    assert!(err_msg.contains("function") && err_msg.contains("serialize"));
+    assert!(err_msg.contains("cannot convert lambda to JSON"));
 }
 
-#[test]
+#[test_log::test]
 fn structured_attrs_false() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "normal";
             builder = "/bin/sh";
@@ -538,9 +566,9 @@ fn structured_attrs_false() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn ignore_nulls_true() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "ignore";
             builder = "/bin/sh";
@@ -560,9 +588,9 @@ fn ignore_nulls_true() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn ignore_nulls_false() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "keep";
             builder = "/bin/sh";
@@ -583,9 +611,9 @@ fn ignore_nulls_false() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn ignore_nulls_with_structured_attrs() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "combined";
             builder = "/bin/sh";
@@ -607,9 +635,9 @@ fn ignore_nulls_with_structured_attrs() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn all_features_combined() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "all";
             builder = "/bin/sh";
@@ -634,14 +662,15 @@ fn all_features_combined() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn fixed_output_with_structured_attrs() {
-    let result = eval(
+    let result = eval_deep(
         r#"derivation {
             name = "fixstruct";
             builder = "/bin/sh";
             system = "x86_64-linux";
-            outputHash = "abc123";
+            outputHash = "0000000000000000000000000000000000000000000000000000000000000000";
+            outputHashAlgo = "sha256";
             __structuredAttrs = true;
             data = { key = "value"; };
         }"#,

nix-js/tests/tests/findfile.rs

@@ -1,8 +1,6 @@
-mod utils;
+use crate::utils::eval;
 
-use utils::eval;
-
-#[test]
+#[test_log::test]
 fn test_find_file_corepkg_fetchurl() {
     let result = eval(
         r#"
@@ -17,13 +15,13 @@ fn test_find_file_corepkg_fetchurl() {
     assert!(result.to_string().contains("fetchurl.nix"));
 }
 
-#[test]
+#[test_log::test]
 fn test_lookup_path_syntax() {
     let result = eval(r#"<nix/fetchurl.nix>"#);
     assert!(result.to_string().contains("fetchurl.nix"));
 }
 
-#[test]
+#[test_log::test]
 fn test_import_corepkg() {
     let result = eval(
         r#"

nix-js/tests/tests/free_globals.rs

@@ -1,24 +1,23 @@
-mod utils;
-
 use nix_js::value::{List, Value};
-use utils::eval;
 
-#[test]
+use crate::utils::{eval, eval_result};
+
+#[test_log::test]
 fn true_literal() {
     assert_eq!(eval("true"), Value::Bool(true));
 }
 
-#[test]
+#[test_log::test]
 fn false_literal() {
     assert_eq!(eval("false"), Value::Bool(false));
 }
 
-#[test]
+#[test_log::test]
 fn null_literal() {
     assert_eq!(eval("null"), Value::Null);
 }
 
-#[test]
+#[test_log::test]
 fn map_function() {
     assert_eq!(
         eval("map (x: x * 2) [1 2 3]"),
@@ -26,23 +25,23 @@ fn map_function() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn is_null_function() {
     assert_eq!(eval("isNull null"), Value::Bool(true));
     assert_eq!(eval("isNull 5"), Value::Bool(false));
 }
 
-#[test]
+#[test_log::test]
 fn shadow_true() {
     assert_eq!(eval("let true = false; in true"), Value::Bool(false));
 }
 
-#[test]
+#[test_log::test]
 fn shadow_map() {
     assert_eq!(eval("let map = x: y: x; in map 1 2"), Value::Int(1));
 }
 
-#[test]
+#[test_log::test]
 fn mixed_usage() {
     assert_eq!(
         eval("if true then map (x: x + 1) [1 2] else []"),
@@ -50,7 +49,7 @@ fn mixed_usage() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn in_let_bindings() {
     assert_eq!(
         eval("let x = true; y = false; in x && y"),
@@ -58,18 +57,18 @@ fn in_let_bindings() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn shadow_in_function() {
     assert_eq!(eval("(true: true) false"), Value::Bool(false));
 }
 
-#[test]
+#[test_log::test]
 fn throw_function() {
-    let result = utils::eval_result("throw \"error message\"");
+    let result = eval_result("throw \"error message\"");
     assert!(result.is_err());
 }
 
-#[test]
+#[test_log::test]
 fn to_string_function() {
     assert_eq!(eval("toString 42"), Value::String("42".to_string()));
 }

nix-js/tests/tests/functions.rs

@@ -1,20 +1,19 @@
-mod utils;
-
 use nix_js::value::Value;
-use utils::{eval, eval_result};
 
-#[test]
+use crate::utils::{eval, eval_result};
+
+#[test_log::test]
 fn required_parameters() {
     assert_eq!(eval("({ a, b }: a + b) { a = 1; b = 2; }"), Value::Int(3));
 }
 
-#[test]
+#[test_log::test]
 fn missing_required_parameter() {
     let result = eval_result("({ a, b }: a + b) { a = 1; }");
     assert!(result.is_err());
 }
 
-#[test]
+#[test_log::test]
 fn all_required_parameters_present() {
     assert_eq!(
         eval("({ x, y, z }: x + y + z) { x = 1; y = 2; z = 3; }"),
@@ -22,13 +21,13 @@ fn all_required_parameters_present() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn reject_unexpected_arguments() {
     let result = eval_result("({ a, b }: a + b) { a = 1; b = 2; c = 3; }");
     assert!(result.is_err());
 }
 
-#[test]
+#[test_log::test]
 fn ellipsis_accepts_extra_arguments() {
     assert_eq!(
         eval("({ a, b, ... }: a + b) { a = 1; b = 2; c = 3; }"),
@@ -36,12 +35,12 @@ fn ellipsis_accepts_extra_arguments() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn default_parameters() {
     assert_eq!(eval("({ a, b ? 5 }: a + b) { a = 1; }"), Value::Int(6));
 }
 
-#[test]
+#[test_log::test]
 fn override_default_parameter() {
     assert_eq!(
         eval("({ a, b ? 5 }: a + b) { a = 1; b = 10; }"),
@@ -49,7 +48,7 @@ fn override_default_parameter() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn at_pattern_alias() {
     assert_eq!(
         eval("(args@{ a, b }: args.a + args.b) { a = 1; b = 2; }"),
@@ -57,17 +56,17 @@ fn at_pattern_alias() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn simple_parameter_no_validation() {
     assert_eq!(eval("(x: x.a + x.b) { a = 1; b = 2; }"), Value::Int(3));
 }
 
-#[test]
+#[test_log::test]
 fn simple_parameter_accepts_any_argument() {
     assert_eq!(eval("(x: x) 42"), Value::Int(42));
 }
 
-#[test]
+#[test_log::test]
 fn nested_function_parameters() {
     assert_eq!(
         eval("({ a }: { b }: a + b) { a = 5; } { b = 3; }"),
@@ -75,12 +74,12 @@ fn nested_function_parameters() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn pattern_param_simple_reference_in_default() {
     assert_eq!(eval("({ a, b ? a }: b) { a = 10; }"), Value::Int(10));
 }
 
-#[test]
+#[test_log::test]
 fn pattern_param_multiple_references_in_default() {
     assert_eq!(
         eval("({ a, b ? a + 5, c ? 1 }: b + c) { a = 10; }"),
@@ -88,7 +87,7 @@ fn pattern_param_multiple_references_in_default() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn pattern_param_mutual_reference() {
     assert_eq!(
         eval("({ a, b ? c + 1, c ? 5 }: b) { a = 1; }"),
@@ -96,7 +95,7 @@ fn pattern_param_mutual_reference() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn pattern_param_override_mutual_reference() {
     assert_eq!(
         eval("({ a, b ? c + 1, c ? 5 }: b) { a = 1; c = 10; }"),
@@ -104,7 +103,7 @@ fn pattern_param_override_mutual_reference() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn pattern_param_reference_list() {
     assert_eq!(
         eval("({ a, b ? [ a 2 ] }: builtins.elemAt b 0) { a = 42; }"),
@@ -112,7 +111,7 @@ fn pattern_param_reference_list() {
     );
 }
 
-#[test]
+#[test_log::test]
 fn pattern_param_alias_in_default() {
     assert_eq!(
         eval("(args@{ a, b ? args.a + 10 }: b) { a = 5; }"),

nix-js/tests/tests/io_operations.rs

@@ -1,12 +1,10 @@
-mod utils;
-
 use nix_js::context::Context;
 use nix_js::error::Source;
 use nix_js::value::Value;
 
 use crate::utils::{eval, eval_result};
 
-#[test]
+#[test_log::test]
 fn import_absolute_path() {
     let temp_dir = tempfile::tempdir().unwrap();
     let lib_path = temp_dir.path().join("nix_test_lib.nix");
@@ -17,7 +15,7 @@ fn import_absolute_path() {
     assert_eq!(eval(&expr), Value::Int(8));
 }
 
-#[test]
+#[test_log::test]
 fn import_nested() {
     let temp_dir = tempfile::tempdir().unwrap();
 
@@ -35,7 +33,7 @@ fn import_nested() {
     assert_eq!(eval(&expr), Value::Int(30));
 }
 
-#[test]
+#[test_log::test]
 fn import_relative_path() {
     let temp_dir = tempfile::tempdir().unwrap();
     let subdir = temp_dir.path().join("subdir");
@@ -66,7 +64,7 @@ fn import_relative_path() {
     assert_eq!(eval(&expr), Value::Int(7));
 }
 
-#[test]
+#[test_log::test]
 fn import_returns_function() {
     let temp_dir = tempfile::tempdir().unwrap();
     let func_path = temp_dir.path().join("nix_test_func.nix");
@@ -76,7 +74,7 @@ fn import_returns_function() {
     assert_eq!(eval(&expr), Value::Int(10));
 }
 
-#[test]
+#[test_log::test]
 fn import_with_complex_dependency_graph() {
     let temp_dir = tempfile::tempdir().unwrap();
 
@@ -97,7 +95,7 @@ fn import_with_complex_dependency_graph() {
 
 // Tests for builtins.path
 
-#[test]
+#[test_log::test]
 fn path_with_file() {
     let mut ctx = Context::new().unwrap();
     let temp_dir = tempfile::tempdir().unwrap();
@@ -105,7 +103,7 @@ fn path_with_file() {
     std::fs::write(&test_file, "Hello, World!").unwrap();
 
     let expr = format!(r#"builtins.path {{ path = {}; }}"#, test_file.display());
-    let result = ctx.eval_code(Source::new_eval(expr).unwrap()).unwrap();
+    let result = ctx.eval(Source::new_eval(expr).unwrap()).unwrap();
 
     // Should return a store path string
     if let Value::String(store_path) = result {
@@ -116,7 +114,7 @@ fn path_with_file() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn path_with_custom_name() {
     let temp_dir = tempfile::tempdir().unwrap();
     let test_file = temp_dir.path().join("original.txt");
@@ -136,7 +134,7 @@ fn path_with_custom_name() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn path_with_directory_recursive() {
     let mut ctx = Context::new().unwrap();
     let temp_dir = tempfile::tempdir().unwrap();
@@ -149,7 +147,7 @@ fn path_with_directory_recursive() {
         r#"builtins.path {{ path = {}; recursive = true; }}"#,
         test_dir.display()
     );
-    let result = ctx.eval_code(Source::new_eval(expr).unwrap()).unwrap();
+    let result = ctx.eval(Source::new_eval(expr).unwrap()).unwrap();
 
     if let Value::String(store_path) = result {
         assert!(store_path.starts_with(ctx.get_store_dir()));
@@ -159,7 +157,7 @@ fn path_with_directory_recursive() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn path_flat_with_file() {
     let mut ctx = Context::new().unwrap();
     let temp_dir = tempfile::tempdir().unwrap();
@@ -170,7 +168,7 @@ fn path_flat_with_file() {
         r#"builtins.path {{ path = {}; recursive = false; }}"#,
         test_file.display()
     );
-    let result = ctx.eval_code(Source::new_eval(expr).unwrap()).unwrap();
+    let result = ctx.eval(Source::new_eval(expr).unwrap()).unwrap();
 
     if let Value::String(store_path) = result {
         assert!(store_path.starts_with(ctx.get_store_dir()));
@@ -179,7 +177,7 @@ fn path_flat_with_file() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn path_flat_with_directory_fails() {
     let temp_dir = tempfile::tempdir().unwrap();
     let test_dir = temp_dir.path().join("mydir");
@@ -196,7 +194,7 @@ fn path_flat_with_directory_fails() {
     assert!(err_msg.contains("recursive") || err_msg.contains("regular file"));
 }
 
-#[test]
+#[test_log::test]
 fn path_nonexistent_fails() {
     let expr = r#"builtins.path { path = "/nonexistent/path/that/should/not/exist"; }"#;
     let result = eval_result(expr);
@@ -206,7 +204,7 @@ fn path_nonexistent_fails() {
     assert!(err_msg.contains("does not exist"));
 }
 
-#[test]
+#[test_log::test]
 fn path_missing_path_param() {
     let expr = r#"builtins.path { name = "test"; }"#;
     let result = eval_result(expr);
@@ -216,7 +214,7 @@ fn path_missing_path_param() {
     assert!(err_msg.contains("path") && err_msg.contains("required"));
 }
 
-#[test]
+#[test_log::test]
 fn path_with_sha256() {
     let temp_dir = tempfile::tempdir().unwrap();
     let test_file = temp_dir.path().join("hash_test.txt");
@@ -243,7 +241,7 @@ fn path_with_sha256() {
     assert_eq!(store_path1, store_path2);
 }
 
-#[test]
+#[test_log::test]
 fn path_deterministic() {
     let temp_dir = tempfile::tempdir().unwrap();
     let test_file = temp_dir.path().join("deterministic.txt");
@@ -261,7 +259,7 @@ fn path_deterministic() {
     assert_eq!(result1, result2);
 }
 
-#[test]
+#[test_log::test]
 fn read_file_type_regular_file() {
     let temp_dir = tempfile::tempdir().unwrap();
     let test_file = temp_dir.path().join("test.txt");
@@ -271,7 +269,7 @@ fn read_file_type_regular_file() {
     assert_eq!(eval(&expr), Value::String("regular".to_string()));
 }
 
-#[test]
+#[test_log::test]
 fn read_file_type_directory() {
     let temp_dir = tempfile::tempdir().unwrap();
     let test_dir = temp_dir.path().join("testdir");
@@ -281,7 +279,7 @@ fn read_file_type_directory() {
     assert_eq!(eval(&expr), Value::String("directory".to_string()));
 }
 
-#[test]
+#[test_log::test]
 fn read_file_type_symlink() {
     let temp_dir = tempfile::tempdir().unwrap();
     let target = temp_dir.path().join("target.txt");
@@ -299,7 +297,7 @@ fn read_file_type_symlink() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn read_dir_basic() {
     let temp_dir = tempfile::tempdir().unwrap();
     let test_dir = temp_dir.path().join("readdir_test");
@@ -331,7 +329,7 @@ fn read_dir_basic() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn read_dir_empty() {
     let temp_dir = tempfile::tempdir().unwrap();
     let test_dir = temp_dir.path().join("empty_dir");
@@ -347,7 +345,7 @@ fn read_dir_empty() {
     }
 }
 
-#[test]
+#[test_log::test]
 fn read_dir_nonexistent_fails() {
     let expr = r#"builtins.readDir "/nonexistent/directory""#;
     let result = eval_result(expr);
@@ -355,7 +353,7 @@ fn read_dir_nonexistent_fails() {
     assert!(result.is_err());
 }
 
-#[test]
+#[test_log::test]
 fn read_dir_on_file_fails() {
     let temp_dir = tempfile::tempdir().unwrap();
     let test_file = temp_dir.path().join("test.txt");

nix-js/tests/tests/lang.rs

@@ -1,7 +1,5 @@
 #![allow(non_snake_case)]
 
-mod utils;
-
 use std::path::PathBuf;
 
 use nix_js::context::Context;
@@ -9,18 +7,23 @@ use nix_js::error::Source;
 use nix_js::value::Value;
 
 fn get_lang_dir() -> PathBuf {
-    PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("tests/lang")
+    PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("tests/tests/lang")
 }
 
-fn eval_file(name: &str) -> Result<Value, String> {
+fn eval_file(name: &str) -> Result<(Value, Source), String> {
     let lang_dir = get_lang_dir();
     let nix_path = lang_dir.join(format!("{name}.nix"));
 
     let expr = format!(r#"import "{}""#, nix_path.display());
 
     let mut ctx = Context::new().map_err(|e| e.to_string())?;
-    let source = Source::new_eval(expr).map_err(|e| e.to_string())?;
-    ctx.eval_code(source).map_err(|e| e.to_string())
+    let source = Source {
+        ty: nix_js::error::SourceType::File(nix_path.into()),
+        src: expr.into(),
+    };
+    ctx.eval_deep(source.clone())
+        .map(|val| (val, source))
+        .map_err(|e| e.to_string())
 }
 
 fn read_expected(name: &str) -> String {
@@ -33,13 +36,13 @@ fn read_expected(name: &str) -> String {
 }
 
 fn format_value(value: &Value) -> String {
-    value.to_string()
+    value.display_compat().to_string()
 }
 
 macro_rules! eval_okay_test {
     ($(#[$attr:meta])* $name:ident$(, $pre:expr)?) => {
         $(#[$attr])*
-        #[test]
+        #[test_log::test]
         fn $name() {
             $(($pre)();)?
             let test_name = concat!("eval-okay-", stringify!($name))
@@ -47,8 +50,17 @@ macro_rules! eval_okay_test {
                 .replace("r#", "");
             let result = eval_file(&test_name);
             match result {
-                Ok(value) => {
+                Ok((value, source)) => {
                     let actual = format_value(&value);
+                    let actual = actual.replace(
+                        source
+                            .get_dir()
+                            .parent()
+                            .unwrap()
+                            .to_string_lossy()
+                            .as_ref(),
+                        "/pwd",
+                    );
                     let expected = read_expected(&test_name);
                     assert_eq!(actual, expected, "Output mismatch for {}", test_name);
                 }
@@ -62,7 +74,7 @@ macro_rules! eval_okay_test {
 
 macro_rules! eval_fail_test {
     ($name:ident) => {
-        #[test]
+        #[test_log::test]
         fn $name() {
             let test_name = concat!("eval-fail-", stringify!($name))
                 .replace("_", "-")
@@ -86,8 +98,14 @@ eval_okay_test!(attrs2);
 eval_okay_test!(attrs3);
 eval_okay_test!(attrs4);
 eval_okay_test!(attrs5);
-eval_okay_test!(#[ignore = "__overrides is not supported"] attrs6);
-eval_okay_test!(#[ignore = "requires --arg/--argstr CLI flags"] autoargs);
+eval_okay_test!(
+    #[ignore = "__overrides is not supported"]
+    attrs6
+);
+eval_okay_test!(
+    #[ignore = "requires --arg/--argstr CLI flags"]
+    autoargs
+);
 eval_okay_test!(backslash_newline_1);
 eval_okay_test!(backslash_newline_2);
 eval_okay_test!(baseNameOf);
@@ -102,7 +120,7 @@ eval_okay_test!(concatmap);
 eval_okay_test!(concatstringssep);
 eval_okay_test!(context);
 eval_okay_test!(context_introspection);
-eval_okay_test!(#[ignore = "not implemented: convertHash"] convertHash);
+eval_okay_test!(convertHash);
 eval_okay_test!(curpos);
 eval_okay_test!(deepseq);
 eval_okay_test!(delayed_with);
@@ -117,7 +135,10 @@ eval_okay_test!(empty_args);
 eval_okay_test!(eq);
 eval_okay_test!(eq_derivations);
 eval_okay_test!(filter);
-eval_okay_test!(#[ignore = "not implemented: flakeRefToString"] flake_ref_to_string);
+eval_okay_test!(
+    #[ignore = "not implemented: flakeRefToString"]
+    flake_ref_to_string
+);
 eval_okay_test!(flatten);
 eval_okay_test!(float);
 eval_okay_test!(floor_ceil);
@@ -126,25 +147,29 @@ eval_okay_test!(foldlStrict_lazy_elements);
 eval_okay_test!(foldlStrict_lazy_initial_accumulator);
 eval_okay_test!(fromjson);
 eval_okay_test!(fromjson_escapes);
-eval_okay_test!(#[ignore = "not implemented: fromTOML"] fromTOML);
-eval_okay_test!(#[ignore = "not implemented: fromTOML"] fromTOML_timestamps);
+eval_okay_test!(fromTOML);
+eval_okay_test!(
+    #[ignore = "timestamps are not supported"]
+    fromTOML_timestamps
+);
 eval_okay_test!(functionargs);
-eval_okay_test!(#[ignore = "not implemented: hashFile"] hashfile);
-eval_okay_test!(#[ignore = "not implemented: hashString"] hashstring);
+eval_okay_test!(hashfile);
+eval_okay_test!(hashstring);
 eval_okay_test!(getattrpos);
 eval_okay_test!(getattrpos_functionargs);
 eval_okay_test!(getattrpos_undefined);
 eval_okay_test!(getenv, || {
-    unsafe {
-        std::env::set_var("TEST_VAR", "foo")
-    };
+    unsafe { std::env::set_var("TEST_VAR", "foo") };
 });
-eval_okay_test!(#[ignore = "not implemented: hashString"] groupBy);
+eval_okay_test!(groupBy);
 eval_okay_test!(r#if);
 eval_okay_test!(ind_string);
-eval_okay_test!(#[ignore = "not implemented: scopedImport"] import);
+eval_okay_test!(import);
 eval_okay_test!(inherit_attr_pos);
-eval_okay_test!(inherit_from);
+eval_okay_test!(
+    #[ignore = "__overrides is not supported"]
+    inherit_from
+);
 eval_okay_test!(intersectAttrs);
 eval_okay_test!(r#let);
 eval_okay_test!(list);
@@ -156,12 +181,22 @@ eval_okay_test!(merge_dynamic_attrs);
 eval_okay_test!(nested_with);
 eval_okay_test!(new_let);
 eval_okay_test!(null_dynamic_attrs);
-eval_okay_test!(#[ignore = "__overrides is not supported"] overrides);
-eval_okay_test!(#[ignore = "not implemented: parseFlakeRef"] parse_flake_ref);
+eval_okay_test!(
+    #[ignore = "__overrides is not supported"]
+    overrides
+);
+eval_okay_test!(
+    #[ignore = "not implemented: parseFlakeRef"]
+    parse_flake_ref
+);
 eval_okay_test!(partition);
 eval_okay_test!(path);
 eval_okay_test!(pathexists);
-eval_okay_test!(path_string_interpolation);
+eval_okay_test!(path_string_interpolation, || {
+    unsafe {
+        std::env::set_var("HOME", "/fake-home");
+    }
+});
 eval_okay_test!(patterns);
 eval_okay_test!(print);
 eval_okay_test!(readDir);
@@ -177,7 +212,10 @@ eval_okay_test!(remove);
 eval_okay_test!(repeated_empty_attrs);
 eval_okay_test!(repeated_empty_list);
 eval_okay_test!(replacestrings);
-eval_okay_test!(#[ignore = "requires -I CLI flags"] search_path);
+eval_okay_test!(
+    #[ignore = "requires -I CLI flags"]
+    search_path
+);
 eval_okay_test!(scope_1);
 eval_okay_test!(scope_2);
 eval_okay_test!(scope_3);
@@ -192,15 +230,18 @@ eval_okay_test!(strings_as_attrs_names);
 eval_okay_test!(substring);
 eval_okay_test!(substring_context);
 eval_okay_test!(symlink_resolution);
-eval_okay_test!(tail_call_1);
+eval_okay_test!(
+    #[ignore = "TCO not implemented, also disabled in CppNix"]
+    tail_call_1
+);
 eval_okay_test!(tojson);
-eval_okay_test!(#[ignore = "not implemented: toXML"] toxml);
-eval_okay_test!(#[ignore = "not implemented: toXML"] toxml2);
+eval_okay_test!(toxml);
+eval_okay_test!(toxml2);
 eval_okay_test!(tryeval);
 eval_okay_test!(types);
 eval_okay_test!(versions);
 eval_okay_test!(with);
-eval_okay_test!(#[ignore = "not implemented: hashString"] zipAttrsWith);
+eval_okay_test!(zipAttrsWith);
 
 eval_fail_test!(fail_abort);
 eval_fail_test!(fail_addDrvOutputDependencies_empty_context);

nix-js/tests/tests/lang/data

@@ -0,0 +1 @@
+foo