refactor

Cargo.toml

@@ -2,8 +2,35 @@
 resolver = "3"
 members = [
     "fix",
+    "fix-builtins",
+    "fix-codegen",
+    "fix-common",
+    "fix-error",
+    "fix-ir",
+    "fix-vm",
 ]
 
 [profile.profiling]
 inherits = "release"
 debug = true
+
+[workspace.dependencies]
+bumpalo = { version = "3.20", features = [
+    "allocator-api2",
+    "boxed",
+    "collections",
+] }
+ghost-cell = "0.2"
+hashbrown = "0.16"
+num_enum = "0.7.5"
+smallvec = "1.15"
+ere = "0.2"
+string-interner = "0.19"
+rnix = "0.14"
+rowan = "0.16"
+likely_stable = "0.1"
+
+[workspace.dependencies.gc-arena]
+git = "https://github.com/kyren/gc-arena"
+rev = "75671ae03f53718357b741ed4027560f14e90836"
+features = ["allocator-api2", "hashbrown", "smallvec"]

fix-builtins/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "fix-builtins"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+num_enum = { workspace = true }
+gc-arena = { workspace = true }

fix-builtins/src/lib.rs

@@ -0,0 +1,125 @@
+use gc_arena::Collect;
+use num_enum::TryFromPrimitive;
+
+macro_rules! define_builtins {
+    ($(($name:literal, $variant:ident, $arity:expr)),* $(,)?) => {
+        /// Builtin function registry.
+        /// Array index IS the PrimOp id. (name, arity) pairs.
+        pub const BUILTINS: &[(&str, u8)] = &[
+            $(($name, $arity),)*
+        ];
+
+        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, TryFromPrimitive, Collect)]
+        #[repr(u8)]
+        #[collect(require_static)]
+        pub enum BuiltinId {
+            $($variant,)*
+        }
+    };
+}
+
+define_builtins! {
+    ("abort",                    Abort,                    1),
+    ("__add",                      Add,                      2),
+    ("__addErrorContext",          AddErrorContext,           2),
+    ("__all",                      All,                      2),
+    ("__any",                      Any,                      2),
+    ("__appendContext",            AppendContext,             2),
+    ("__attrNames",                AttrNames,                1),
+    ("__attrValues",               AttrValues,               1),
+    ("baseNameOf",               BaseNameOf,               1),
+    ("__bitAnd",                   BitAnd,                   2),
+    ("__bitOr",                    BitOr,                    2),
+    ("__bitXor",                   BitXor,                   2),
+    ("break",                    Break,                    1),
+    ("__catAttrs",                 CatAttrs,                 2),
+    ("__ceil",                     Ceil,                     1),
+    ("__compareVersions",          CompareVersions,          2),
+    ("__concatLists",              ConcatLists,              1),
+    ("__concatMap",                ConcatMap,                2),
+    ("__concatStringsSep",         ConcatStringsSep,         2),
+    ("__convertHash",              ConvertHash,              1),
+    ("__deepSeq",                  DeepSeq,                  2),
+    ("derivation",               Derivation,               1),
+    ("derivationStrict",         DerivationStrict,         1),
+    ("dirOf",                    DirOf,                    1),
+    ("__div",                      Div,                      2),
+    ("__elem",                     Elem,                     2),
+    ("__elemAt",                   ElemAt,                   2),
+    ("fetchGit",                 FetchGit,                 1),
+    ("fetchMercurial",           FetchMercurial,           1),
+    ("fetchTarball",             FetchTarball,             1),
+    ("fetchTree",                FetchTree,                1),
+    ("__fetchurl",                 FetchUrl,                 1),
+    ("__filter",                   Filter,                   2),
+    ("__filterSource",             FilterSource,             2),
+    ("__findFile",                 FindFile,                 2),
+    ("__floor",                    Floor,                    1),
+    ("__foldl'",                   FoldlStrict,              3),
+    ("__fromJSON",                 FromJSON,                 1),
+    ("fromTOML",                 FromTOML,                 1),
+    ("__functionArgs",             FunctionArgs,             1),
+    ("__genList",                  GenList,                  2),
+    ("__genericClosure",           GenericClosure,           1),
+    ("__getAttr",                  GetAttr,                  2),
+    ("__getContext",               GetContext,               1),
+    ("__getEnv",                   GetEnv,                   1),
+    ("__groupBy",                  GroupBy,                  2),
+    ("__hasAttr",                  HasAttr,                  2),
+    ("__hasContext",               HasContext,               1),
+    ("__hashFile",                 HashFile,                 2),
+    ("__hashString",               HashString,               2),
+    ("__head",                     Head,                     1),
+    ("import",                   Import,                   1),
+    ("__intersectAttrs",           IntersectAttrs,           2),
+    ("__isAttrs",                  IsAttrs,                  1),
+    ("__isBool",                   IsBool,                   1),
+    ("__isFloat",                  IsFloat,                  1),
+    ("__isFunction",               IsFunction,               1),
+    ("__isInt",                    IsInt,                    1),
+    ("__isList",                   IsList,                   1),
+    ("isNull",                   IsNull,                   1),
+    ("__isPath",                   IsPath,                   1),
+    ("__isString",                 IsString,                 1),
+    ("__length",                   Length,                   1),
+    ("__lessThan",                 LessThan,                 2),
+    ("__listToAttrs",              ListToAttrs,              1),
+    ("map",                      Map,                      2),
+    ("__mapAttrs",                 MapAttrs,                 2),
+    ("__match",                    Match,                    2),
+    ("__mul",                      Mul,                      2),
+    ("null",                     Null,                     0), // constant, not a function
+    ("__parseDrvName",             ParseDrvName,             1),
+    ("__partition",                Partition,                2),
+    ("__path",                     Path,                     1),
+    ("__pathExists",               PathExists,               1),
+    ("placeholder",              Placeholder,              1),
+    ("__readDir",                  ReadDir,                  1),
+    ("__readFile",                 ReadFile,                 1),
+    ("__readFileType",             ReadFileType,             1),
+    ("removeAttrs",              RemoveAttrs,              2),
+    ("__replaceStrings",           ReplaceStrings,           3),
+    ("scopedImport",             ScopedImport,             2),
+    ("__seq",                      Seq,                      2),
+    ("__sort",                     Sort,                     2),
+    ("__split",                    Split,                    2),
+    ("__splitVersion",             SplitVersion,             1),
+    ("__storePath",                StorePath,                1),
+    ("__stringLength",             StringLength,             1),
+    ("__sub",                      Sub,                      2),
+    ("__substring",                Substring,                3),
+    ("__tail",                     Tail,                     1),
+    ("throw",                    Throw,                    1),
+    ("__toFile",                   ToFile,                   2),
+    ("__toJSON",                   ToJSON,                   1),
+    ("__toPath",                   ToPath,                   1),
+    ("toString",                 ToString,                 1),
+    ("__toXML",                    ToXML,                    1),
+    ("__trace",                    Trace,                    2),
+    ("__tryEval",                  TryEval,                  1),
+    ("__typeOf",                   TypeOf,                   1),
+    ("__unsafeDiscardStringContext", UnsafeDiscardStringContext, 1),
+    ("__unsafeGetAttrPos",         UnsafeGetAttrPos,         2),
+    ("__warn",                     Warn,                     2),
+    ("__zipAttrsWith",             ZipAttrsWith,             2),
+}

fix-codegen/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "fix-codegen"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+gc-arena = { workspace = true }
+hashbrown = { workspace = true }
+num_enum = { workspace = true }
+rnix = { workspace = true }
+string-interner = { workspace = true }
+
+fix-builtins = { path = "../fix-builtins" }
+fix-common = { path = "../fix-common" }
+fix-ir = { path = "../fix-ir" }

fix-codegen/src/lib.rs

@@ -1,30 +1,21 @@
 use std::ops::Deref;
 
-use gc_arena::Collect;
+use fix_builtins::{BUILTINS, BuiltinId};
+use fix_common::StringId;
+use fix_ir::{Attr, BinOpKind, Ir, Param, RawIrRef, ThunkId, UnOpKind};
 use hashbrown::HashMap;
 use num_enum::TryFromPrimitive;
 use rnix::TextRange;
 use string_interner::Symbol as _;
 
-use crate::ir::{Attr, BinOpKind, Ir, Param, RawIrRef, StringId, ThunkId, UnOpKind};
-use crate::runtime::BUILTINS;
-use crate::runtime::value::{Null, PrimOp, StaticValue};
+pub struct InstructionPtr(pub usize);
 
-pub struct InstructionPtr(pub(crate) usize);
-
-#[derive(Collect)]
-#[collect(require_static)]
-pub struct Bytecode {
-    pub code: Box<[u8]>,
-    pub current_dir: String,
-}
-
-pub(crate) trait BytecodeContext {
+pub trait BytecodeContext {
     fn intern_string(&mut self, s: &str) -> StringId;
     fn register_span(&mut self, range: TextRange) -> u32;
     fn get_code(&self) -> &[u8];
     fn get_code_mut(&mut self) -> &mut Vec<u8>;
-    fn add_constant(&mut self, val: crate::runtime::value::StaticValue) -> u32;
+    fn add_constant(&mut self, val: Const) -> u32;
 }
 
 #[repr(u8)]
@@ -49,7 +40,6 @@ pub enum Op {
     MakePatternClosure,
 
     Call,
-    CallNoSpan,
 
     MakeAttrs,
     MakeEmptyAttrs,
@@ -98,6 +88,8 @@ pub enum Op {
     LoadScopedBinding,
 
     Return,
+
+    Illegal,
 }
 
 struct ScopeInfo {
@@ -110,22 +102,39 @@ struct BytecodeEmitter<'a, Ctx: BytecodeContext> {
     scope_stack: Vec<ScopeInfo>,
 }
 
-pub(crate) const OPERAND_CONST: u8 = 0;
-pub(crate) const OPERAND_LOCAL: u8 = 1;
-pub(crate) const OPERAND_BUILTINS: u8 = 2;
-pub(crate) const OPERAND_BIGINT: u8 = 3;
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, TryFromPrimitive)]
+pub enum OperandType {
+    Const,
+    Local,
+    Builtins,
+    BigInt,
+}
 
-pub(crate) const KEY_STATIC: u8 = 0;
-pub(crate) const KEY_DYNAMIC: u8 = 1;
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, TryFromPrimitive)]
+pub enum AttrKeyType {
+    Static,
+    Dynamic,
+}
 
-enum InlineOperand {
-    Const(StaticValue),
+pub enum Const {
+    Smi(i32),
+    Float(f64),
+    Bool(bool),
+    String(StringId),
+    PrimOp { id: BuiltinId, arity: u8 },
+    Null,
+}
+
+pub enum InlineOperand {
+    Const(Const),
     Local { layer: u16, local: u32 },
     Builtins,
     BigInt(i64),
 }
 
-pub(crate) fn compile_bytecode(ir: RawIrRef<'_>, ctx: &mut impl BytecodeContext) -> InstructionPtr {
+pub fn compile_bytecode(ir: RawIrRef<'_>, ctx: &mut impl BytecodeContext) -> InstructionPtr {
     let ip = ctx.get_code().len();
     let mut emitter = BytecodeEmitter::new(ctx);
     emitter.emit_toplevel(ir);
@@ -144,17 +153,17 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         match ir.deref() {
             &Ir::Int(x) => {
                 if x <= i32::MAX as i64 {
-                    InlineOperand::Const(StaticValue::new_inline(x as i32))
+                    InlineOperand::Const(Const::Smi(x as i32))
                 } else {
                     InlineOperand::BigInt(x)
                 }
             }
-            &Ir::Float(x) => InlineOperand::Const(StaticValue::new_float(x)),
-            &Ir::Bool(b) => InlineOperand::Const(StaticValue::new_inline(b)),
-            Ir::Null => InlineOperand::Const(StaticValue::new_inline(Null)),
+            &Ir::Float(x) => InlineOperand::Const(Const::Float(x)),
+            &Ir::Bool(b) => InlineOperand::Const(Const::Bool(b)),
+            Ir::Null => InlineOperand::Const(Const::Null),
             Ir::Str(s) => {
                 let sid = self.ctx.intern_string(s.deref());
-                InlineOperand::Const(StaticValue::new_inline(sid))
+                InlineOperand::Const(Const::String(sid))
             }
             &Ir::Thunk(id) => {
                 let (layer, local) = self.resolve_thunk(id);
@@ -166,7 +175,7 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
             },
             &Ir::Builtin(id) => {
                 let arity = BUILTINS[id as usize].1;
-                InlineOperand::Const(StaticValue::new_inline(PrimOp { id, arity }))
+                InlineOperand::Const(Const::PrimOp { id, arity })
             }
             Ir::Builtins => InlineOperand::Builtins,
             _ => panic!("cannot classify IR node as inline operand"),
@@ -177,19 +186,19 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         match operand {
             InlineOperand::Const(val) => {
                 let idx = self.ctx.add_constant(val);
-                self.emit_u8(OPERAND_CONST);
+                self.emit_u8(OperandType::Const as u8);
                 self.emit_u32(idx);
             }
             InlineOperand::Local { layer, local } => {
-                self.emit_u8(OPERAND_LOCAL);
+                self.emit_u8(OperandType::Local as u8);
                 self.emit_u8(layer as u8);
                 self.emit_u32(local);
             }
             InlineOperand::Builtins => {
-                self.emit_u8(OPERAND_BUILTINS);
+                self.emit_u8(OperandType::Builtins as u8);
             }
             InlineOperand::BigInt(val) => {
-                self.emit_u8(OPERAND_BIGINT);
+                self.emit_u8(OperandType::BigInt as u8);
                 self.emit_i64(val);
             }
         }
@@ -566,12 +575,10 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                     }
                 }
             }
-            &Ir::Call { func, arg, span } => {
+            &Ir::Call { func, arg, .. } => {
                 self.emit_expr(arg);
                 self.emit_expr(func);
-                let span_id = self.ctx.register_span(span);
                 self.emit_op(Op::Call);
-                self.emit_u32(span_id);
             }
             &Ir::Arg { layer } => {
                 self.emit_load(layer.try_into().expect("scope too deep!"), 0);
@@ -725,12 +732,12 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
             PipeL => {
                 self.emit_expr(rhs);
                 self.emit_expr(lhs);
-                self.emit_op(Op::CallNoSpan);
+                self.emit_op(Op::Call);
             }
             PipeR => {
                 self.emit_expr(lhs);
                 self.emit_expr(rhs);
-                self.emit_op(Op::CallNoSpan);
+                self.emit_op(Op::Call);
             }
             _ => {
                 self.emit_expr(lhs);
@@ -808,7 +815,7 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
 
     fn emit_attrset(
         &mut self,
-        stcs: &crate::ir::HashMap<'_, StringId, (RawIrRef<'_>, TextRange)>,
+        stcs: &fix_ir::HashMap<'_, StringId, (RawIrRef<'_>, TextRange)>,
         dyns: &[(RawIrRef<'_>, RawIrRef<'_>, TextRange)],
     ) {
         if stcs.is_empty() && dyns.is_empty() {
@@ -821,7 +828,7 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         self.emit_u32(total as u32);
 
         for (&sym, &(val, span)) in stcs.iter() {
-            self.emit_u8(KEY_STATIC);
+            self.emit_u8(AttrKeyType::Static as u8);
             self.emit_str_id(sym);
             let val_operand = self.classify_value(val);
             self.emit_inline_operand(val_operand);
@@ -829,7 +836,7 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
             self.emit_u32(span_id);
         }
         for &(key, val, span) in dyns.iter() {
-            self.emit_u8(KEY_DYNAMIC);
+            self.emit_u8(AttrKeyType::Dynamic as u8);
             let key_operand = self.classify_value(key);
             self.emit_inline_operand(key_operand);
             let val_operand = self.classify_value(val);
@@ -867,11 +874,11 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         for attr in attrpath.iter() {
             match *attr {
                 Attr::Str(sym, _) => {
-                    self.emit_u8(KEY_STATIC);
+                    self.emit_u8(AttrKeyType::Static as u8);
                     self.emit_str_id(sym);
                 }
                 Attr::Dynamic(_, _) => {
-                    self.emit_u8(KEY_DYNAMIC);
+                    self.emit_u8(AttrKeyType::Dynamic as u8);
                 }
             }
         }
@@ -889,11 +896,11 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         for attr in rhs.iter() {
             match *attr {
                 Attr::Str(sym, _) => {
-                    self.emit_u8(KEY_STATIC);
+                    self.emit_u8(AttrKeyType::Static as u8);
                     self.emit_str_id(sym);
                 }
                 Attr::Dynamic(_, _) => {
-                    self.emit_u8(KEY_DYNAMIC);
+                    self.emit_u8(AttrKeyType::Dynamic as u8);
                 }
             }
         }

fix-common/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "fix-common"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+gc-arena = { workspace = true }
+string-interner = { workspace = true }
+ere = { workspace = true }

fix-common/src/lib.rs

@@ -1,14 +1,17 @@
-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::fmt::{Debug, Display, Formatter, Result as FmtResult};
+use std::ops::{Deref, DerefMut};
 
-use derive_more::{Constructor, IsVariant, Unwrap};
+use gc_arena::Collect;
+
+#[repr(transparent)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Collect)]
+#[collect(require_static)]
+pub struct StringId(pub string_interner::symbol::SymbolU32);
 
 /// Represents a Nix symbol, which is used as a key in attribute sets.
-#[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Constructor)]
+#[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Symbol<'a>(Cow<'a, str>);
 
 pub type StaticSymbol = Symbol<'static>;
@@ -60,13 +63,36 @@ impl Deref for Symbol<'_> {
     }
 }
 
+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
+}
+
 /// Represents a Nix attribute set, which is a map from symbols to values.
-#[derive(Constructor, Default, Clone, PartialEq)]
+#[derive(Default, Clone, PartialEq)]
 pub struct AttrSet {
     data: BTreeMap<StaticSymbol, Value>,
 }
 
 impl AttrSet {
+    pub fn new(data: BTreeMap<StaticSymbol, Value>) -> Self {
+        Self { data }
+    }
+
     /// Gets a value by key (string or Symbol).
     pub fn get<'a, 'sym: 'a>(&'a self, key: impl Into<Symbol<'sym>>) -> Option<&'a Value> {
         self.data.get(&key.into())
@@ -154,11 +180,17 @@ impl Display for AttrSetCompatDisplay<'_> {
 }
 
 /// Represents a Nix list, which is a vector of values.
-#[derive(Constructor, Default, Clone, Debug, PartialEq)]
+#[derive(Default, Clone, Debug, PartialEq)]
 pub struct List {
     data: Vec<Value>,
 }
 
+impl List {
+    pub fn new(data: Vec<Value>) -> Self {
+        Self { data }
+    }
+}
+
 impl Deref for List {
     type Target = Vec<Value>;
     fn deref(&self) -> &Self::Target {
@@ -217,7 +249,7 @@ impl Display for ListCompatDisplay<'_> {
 }
 
 /// Represents any possible Nix value that can be returned from an evaluation.
-#[derive(IsVariant, Unwrap, Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 pub enum Value {
     /// An integer value.
     Int(i64),
@@ -248,27 +280,8 @@ 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
-}
-
 /// Wrapper to format a float in Nix style (C printf `%g` with precision 6).
-pub(crate) struct NixFloat(pub f64);
+pub struct NixFloat(pub f64);
 
 impl Display for NixFloat {
     fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {

fix-error/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "fix-error"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+miette = { version = "7.6", features = ["fancy"] }
+thiserror = "2.0"
+rnix = { workspace = true }

fix-error/src/lib.rs

@@ -0,0 +1,223 @@
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+use miette::{Diagnostic, NamedSource, SourceSpan};
+use thiserror::Error;
+
+pub type Result<T> = core::result::Result<T, Box<Error>>;
+
+#[derive(Clone, Debug)]
+pub enum SourceType {
+    /// dir
+    Eval(Arc<PathBuf>),
+    /// dir
+    Repl(Arc<PathBuf>),
+    /// file
+    File(Arc<PathBuf>),
+    /// virtual (name, no path)
+    Virtual(Arc<str>),
+}
+
+#[derive(Clone, Debug)]
+pub struct Source {
+    pub ty: SourceType,
+    pub src: Arc<str>,
+}
+
+impl TryFrom<&str> for Source {
+    type Error = Box<Error>;
+    fn try_from(value: &str) -> Result<Self> {
+        Source::new_eval(value.into())
+    }
+}
+
+impl From<Source> for NamedSource<Arc<str>> {
+    fn from(value: Source) -> Self {
+        let name = value.get_name();
+        NamedSource::new(name, value.src.clone())
+    }
+}
+
+impl Source {
+    pub fn new_file(path: PathBuf) -> std::io::Result<Self> {
+        Ok(Source {
+            src: std::fs::read_to_string(&path)?.into(),
+            ty: SourceType::File(Arc::new(path)),
+        })
+    }
+
+    pub fn new_eval(src: String) -> Result<Self> {
+        Ok(Self {
+            ty: std::env::current_dir()
+                .map_err(|err| Error::internal(format!("Failed to get current working dir: {err}")))
+                .map(Arc::new)
+                .map(SourceType::Eval)?,
+            src: src.into(),
+        })
+    }
+
+    pub fn new_repl(src: String) -> Result<Self> {
+        Ok(Self {
+            ty: std::env::current_dir()
+                .map_err(|err| Error::internal(format!("Failed to get current working dir: {err}")))
+                .map(Arc::new)
+                .map(SourceType::Repl)?,
+            src: src.into(),
+        })
+    }
+
+    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 {
+            Eval(dir) | Repl(dir) => dir.as_ref(),
+            File(file) => file
+                .as_path()
+                .parent()
+                .expect("source file must have a parent dir"),
+            Virtual(_) => Path::new("/"),
+        }
+    }
+
+    pub fn get_name(&self) -> String {
+        match &self.ty {
+            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(),
+        }
+    }
+}
+
+#[derive(Error, Debug, Diagnostic)]
+pub enum Error {
+    #[error("Parse error: {message}")]
+    #[diagnostic(code(nix::parse))]
+    ParseError {
+        #[source_code]
+        src: Option<NamedSource<Arc<str>>>,
+        #[label("error occurred here")]
+        span: Option<SourceSpan>,
+        message: String,
+    },
+
+    #[error("Downgrade error: {message}")]
+    #[diagnostic(code(nix::downgrade))]
+    DowngradeError {
+        #[source_code]
+        src: Option<NamedSource<Arc<str>>>,
+        #[label("{message}")]
+        span: Option<SourceSpan>,
+        message: String,
+    },
+
+    #[error("Evaluation error: {message}")]
+    #[diagnostic(code(nix::eval))]
+    EvalError {
+        #[source_code]
+        src: Option<NamedSource<Arc<str>>>,
+        #[label("error occurred here")]
+        span: Option<SourceSpan>,
+        message: String,
+        #[related]
+        stack_trace: Vec<StackFrame>,
+    },
+
+    #[error("Internal error: {message}")]
+    #[diagnostic(code(nix::internal))]
+    InternalError { message: String },
+
+    #[error("{message}")]
+    #[diagnostic(code(nix::catchable))]
+    Catchable { message: String },
+
+    #[error("Unknown error")]
+    #[diagnostic(code(nix::unknown))]
+    Unknown,
+}
+
+impl Error {
+    pub fn parse_error(msg: String) -> Box<Self> {
+        Error::ParseError {
+            src: None,
+            span: None,
+            message: msg,
+        }
+        .into()
+    }
+
+    pub fn downgrade_error(msg: String, src: Source, span: rnix::TextRange) -> Box<Self> {
+        Error::DowngradeError {
+            src: Some(src.into()),
+            span: Some(text_range_to_source_span(span)),
+            message: msg,
+        }
+        .into()
+    }
+
+    pub fn eval_error(msg: impl Into<String>) -> Box<Self> {
+        Error::EvalError {
+            src: None,
+            span: None,
+            message: msg.into(),
+            stack_trace: Vec::new(),
+        }
+        .into()
+    }
+
+    pub fn internal(msg: String) -> Box<Self> {
+        Error::InternalError { message: msg }.into()
+    }
+
+    pub fn catchable(msg: String) -> Box<Self> {
+        Error::Catchable { message: msg }.into()
+    }
+
+    pub fn with_span(mut self: Box<Self>, span: rnix::TextRange) -> Box<Self> {
+        use Error::*;
+        let source_span = Some(text_range_to_source_span(span));
+        let (ParseError { span, .. } | DowngradeError { span, .. } | EvalError { span, .. }) =
+            self.as_mut()
+        else {
+            return self;
+        };
+        *span = source_span;
+        self
+    }
+
+    pub fn with_source(mut self: Box<Self>, source: Source) -> Box<Self> {
+        use Error::*;
+        let new_src = Some(source.into());
+        let (ParseError { src, .. } | DowngradeError { src, .. } | EvalError { src, .. }) =
+            self.as_mut()
+        else {
+            return self;
+        };
+        *src = new_src;
+        self
+    }
+}
+
+pub fn text_range_to_source_span(range: rnix::TextRange) -> SourceSpan {
+    let start = usize::from(range.start());
+    let len = usize::from(range.end()) - start;
+    SourceSpan::new(start.into(), len)
+}
+
+/// Stack frame types from Nix evaluation
+#[derive(Debug, Clone, Error, Diagnostic)]
+#[error("{message}")]
+pub struct StackFrame {
+    #[label]
+    pub span: SourceSpan,
+    #[help]
+    pub message: String,
+    #[source_code]
+    pub src: NamedSource<Arc<str>>,
+}

fix-ir/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "fix-ir"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+bumpalo = { workspace = true }
+ghost-cell = { workspace = true }
+rnix = { workspace = true }
+rowan = { workspace = true }
+string-interner = { workspace = true }
+hashbrown = { workspace = true }
+num_enum = { workspace = true }
+
+fix-builtins = { path = "../fix-builtins" }
+fix-common = { path = "../fix-common" }
+fix-error = { path = "../fix-error" }

fix-ir/src/downgrade.rs

@@ -1,15 +1,15 @@
 use bumpalo::boxed::Box;
 use bumpalo::collections::{CollectIn, Vec};
+use fix_builtins::BuiltinId;
+use fix_common::Symbol;
+use fix_error::{Error, Result, Source};
 use hashbrown::HashSet;
 use hashbrown::hash_map::Entry;
 use rnix::TextRange;
 use rnix::ast::{self, Expr, HasEntry};
 use rowan::ast::AstNode;
 
-use crate::error::{Error, Result, Source};
-use crate::ir::*;
-use crate::runtime::BuiltinId;
-use crate::value::Symbol;
+use super::*;
 
 trait Require<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>, T> {
     fn require(self, ctx: &Ctx, span: TextRange) -> Result<T>;
@@ -151,8 +151,7 @@ macro_rules! path {
     ($ty:ident) => {
         impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::$ty {
             fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
-                let span = self.syntax().text_range();
-                downgrade_path(self.parts(), span, ctx)
+                downgrade_path(self.parts(), ctx)
             }
         }
     };
@@ -1215,7 +1214,6 @@ fn finalize_pending_value<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW
 
 fn downgrade_path<'id, 'ir>(
     parts: impl IntoIterator<Item = ast::InterpolPart<ast::PathContent>>,
-    _span: rnix::TextRange,
     ctx: &mut impl DowngradeContext<'id, 'ir>,
 ) -> Result<IrRef<'id, 'ir>> {
     let bump = ctx.bump();

fix-ir/src/lib.rs

@@ -4,12 +4,14 @@ use std::ops::Deref;
 use bumpalo::Bump;
 use bumpalo::boxed::Box;
 use bumpalo::collections::Vec;
-use gc_arena::Collect;
+use fix_builtins::{BUILTINS, BuiltinId};
+use fix_common::StringId;
 use ghost_cell::{GhostCell, GhostToken};
+use num_enum::TryFromPrimitive as _;
 use rnix::{TextRange, ast};
-use string_interner::symbol::SymbolU32;
+use string_interner::DefaultStringInterner;
 
-use crate::runtime::BuiltinId;
+pub mod downgrade;
 
 pub type HashMap<'ir, K, V> = hashbrown::HashMap<K, V, hashbrown::DefaultHashBuilder, &'ir Bump>;
 
@@ -157,11 +159,6 @@ pub enum Ir<'ir, Ref> {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct ThunkId(pub usize);
 
-#[repr(transparent)]
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Collect)]
-#[collect(require_static)]
-pub struct StringId(pub SymbolU32);
-
 #[repr(transparent)]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct SpanId(pub u32);
@@ -258,3 +255,47 @@ pub struct Param<'ir> {
     pub optional: Vec<'ir, (StringId, TextRange)>,
     pub ellipsis: bool,
 }
+
+pub fn new_global_env(
+    strings: &mut DefaultStringInterner,
+) -> hashbrown::HashMap<StringId, Ir<'static, RawIrRef<'static>>> {
+    let mut global_env = hashbrown::HashMap::new();
+    let builtins_sym = StringId(strings.get_or_intern("builtins"));
+    global_env.insert(builtins_sym, Ir::Builtins);
+
+    for (idx, &(name, _)) in BUILTINS.iter().enumerate() {
+        let id = BuiltinId::try_from_primitive(idx as u8).expect("infallible");
+        let name = StringId(strings.get_or_intern(name));
+        global_env.insert(name, Ir::Builtin(id));
+    }
+
+    let consts = [
+        (
+            "__currentSystem",
+            Ir::BuiltinConst(StringId(strings.get_or_intern("currentSystem"))),
+        ),
+        ("__langVersion", Ir::Int(6)),
+        (
+            "__nixVersion",
+            Ir::BuiltinConst(StringId(strings.get_or_intern("nixVersion"))),
+        ),
+        (
+            "__storeDir",
+            Ir::BuiltinConst(StringId(strings.get_or_intern("storeDir"))),
+        ),
+        (
+            "__nixPath",
+            Ir::BuiltinConst(StringId(strings.get_or_intern("nixPath"))),
+        ),
+        ("null", Ir::Null),
+        ("true", Ir::Bool(true)),
+        ("false", Ir::Bool(false)),
+    ];
+
+    for (name, ir) in consts {
+        let name = StringId(strings.get_or_intern(name));
+        global_env.insert(name, ir);
+    }
+
+    global_env
+}

fix-vm/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "fix-vm"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+gc-arena = { workspace = true }
+hashbrown = { workspace = true }
+num_enum = { workspace = true }
+smallvec = { workspace = true }
+string-interner = { workspace = true }
+likely_stable = { workspace = true }
+sptr = "0.3"
+
+fix-builtins = { path = "../fix-builtins" }
+fix-codegen = { path = "../fix-codegen" }
+fix-common = { path = "../fix-common" }
+fix-error = { path = "../fix-error" }

fix-vm/src/boxing.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use std::fmt;
 use std::num::NonZeroU8;
 
@@ -22,7 +24,7 @@ impl<T: Default + Copy, const N: usize> ArrayExt<N> for [T; N] {
     }
 }
 
-pub(crate) trait RawStore: Sized {
+pub trait RawStore: Sized {
     fn to_val(self, value: &mut Value);
     fn from_val(value: &Value) -> Self;
 }

fix-vm/src/helpers.rs

@@ -0,0 +1,18 @@
+use fix_error::Error;
+
+use crate::value::StrictValue;
+use crate::{NixNum, VmError};
+
+pub(super) fn vm_err(msg: impl Into<String>) -> VmError {
+    VmError::Uncatchable(Error::eval_error(msg.into()))
+}
+
+pub(super) fn get_num(val: StrictValue<'_>) -> Option<NixNum> {
+    if let Some(i) = val.as_inline::<i32>() {
+        Some(NixNum::Int(i as i64))
+    } else if let Some(gc_i) = val.as_gc::<i64>() {
+        Some(NixNum::Int(*gc_i))
+    } else {
+        val.as_float().map(NixNum::Float)
+    }
+}

fix-vm/src/stack.rs

@@ -1,7 +1,6 @@
 use std::mem::MaybeUninit;
 
 use gc_arena::Collect;
-use smallvec::SmallVec;
 
 pub(super) struct Stack<const N: usize, T> {
     inner: Box<[MaybeUninit<T>; N]>,
@@ -74,15 +73,4 @@ impl<const N: usize, T> Stack<N, T> {
     pub(super) fn len(&self) -> usize {
         self.len
     }
-
-    pub(super) fn pop_n<const M: usize>(&mut self, n: usize) -> SmallVec<[T; M]> {
-        assert!(n <= self.len, "pop_n: not enough items on stack");
-        let mut result = SmallVec::new();
-        let start = self.len - n;
-        for i in start..self.len {
-            result.push(unsafe { self.inner.get_unchecked(i).assume_init_read() });
-        }
-        self.len = start;
-        result
-    }
 }

fix-vm/src/value.rs

@@ -1,25 +1,30 @@
+#![allow(dead_code)]
+
 use std::fmt;
 use std::marker::PhantomData;
 use std::mem::size_of;
 use std::ops::Deref;
 
+use fix_builtins::BuiltinId;
+use fix_common::*;
 use gc_arena::collect::Trace;
-use gc_arena::{Collect, Gc, Mutation, RefLock};
+use gc_arena::{Collect, Gc, GcRefLock, Mutation, RefLock};
 use num_enum::TryFromPrimitive;
-use sealed::sealed;
 use smallvec::SmallVec;
 use string_interner::Symbol;
 use string_interner::symbol::SymbolU32;
 
+use crate::NixNum;
 use crate::boxing::{RawBox, RawStore, RawTag, Value as RawValue};
-use crate::ir::StringId;
-use crate::runtime::builtins::BuiltinId;
 
-#[sealed]
+mod private {
+    pub trait Cealed {}
+}
+
 /// # Safety
 /// 1. TAG must be unique among all implementors.
 /// 2. TAG must be within 1..=7
-pub(crate) unsafe trait Storable {
+pub(crate) unsafe trait Storable: private::Cealed {
     const TAG: (bool, u8);
 }
 pub(crate) trait InlineStorable: Storable + RawStore {}
@@ -31,18 +36,18 @@ macro_rules! define_value_types {
         gc { $($gtype:ty => $gtag:expr, $gname:literal;)* }
     ) => {
         $(
-        #[sealed]
         unsafe impl Storable for $itype {
             const TAG: (bool, u8) = $itag;
         }
         impl InlineStorable for $itype {}
+        impl private::Cealed for $itype {}
         )*
         $(
-        #[sealed]
         unsafe impl Storable for $gtype {
             const TAG: (bool, u8) = $gtag;
         }
         impl GcStorable for $gtype {}
+        impl private::Cealed for $gtype {}
         )*
 
         const _: () = assert!(size_of::<Value<'static>>() == 8);
@@ -98,20 +103,6 @@ macro_rules! define_value_types {
                 }
             }
         }
-
-        impl fmt::Debug for StaticValue {
-            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-                match self.tag() {
-                    None => write!(f, "Float({:?})", unsafe {
-                        self.raw.float().unwrap_unchecked()
-                    }),
-                    $(Some(<$itype as Storable>::TAG) => write!(f, "{}({:?})", $iname, unsafe {
-                        self.as_inline::<$itype>().unwrap_unchecked()
-                    }),)*
-                    Some((neg, val)) => write!(f, "Unknown(neg={neg}, val={val})"),
-                }
-            }
-        }
     };
 }
 
@@ -166,7 +157,7 @@ impl<'gc> Value<'gc> {
     ///
     /// The value must actually store a `Gc<'gc, T>` with the matching type.
     #[inline(always)]
-    unsafe fn load_gc<T: GcStorable>(&self) -> Gc<'gc, T> {
+    unsafe fn load_gc<T: GcStorable>(self) -> Gc<'gc, T> {
         unsafe {
             let rv = self.raw.value().unwrap_unchecked();
             let ptr: *const T = <*const T as RawStore>::from_val(rv);
@@ -176,7 +167,7 @@ impl<'gc> Value<'gc> {
 
     /// Returns the `(negative, val)` tag, or `None` for a float.
     #[inline(always)]
-    fn tag(&self) -> Option<(bool, u8)> {
+    fn tag(self) -> Option<(bool, u8)> {
         self.raw.tag().map(|t| t.neg_val())
     }
 }
@@ -219,24 +210,24 @@ impl<'gc> Value<'gc> {
 
 impl<'gc> Value<'gc> {
     #[inline]
-    pub(crate) fn is_float(&self) -> bool {
+    pub(crate) fn is_float(self) -> bool {
         self.raw.is_float()
     }
 
     #[inline]
-    pub(crate) fn is<T: Storable>(&self) -> bool {
+    pub(crate) fn is<T: Storable>(self) -> bool {
         self.tag() == Some(T::TAG)
     }
 }
 
 impl<'gc> Value<'gc> {
     #[inline]
-    pub(crate) fn as_float(&self) -> Option<f64> {
+    pub(crate) fn as_float(self) -> Option<f64> {
         self.raw.float().copied()
     }
 
     #[inline]
-    pub(crate) fn as_inline<T: InlineStorable>(&self) -> Option<T> {
+    pub(crate) fn as_inline<T: InlineStorable>(self) -> Option<T> {
         if self.is::<T>() {
             Some(unsafe {
                 let rv = self.raw.value().unwrap_unchecked();
@@ -248,7 +239,7 @@ impl<'gc> Value<'gc> {
     }
 
     #[inline]
-    pub(crate) fn as_gc<T: GcStorable>(&self) -> Option<Gc<'gc, T>> {
+    pub(crate) fn as_gc<T: GcStorable>(self) -> Option<Gc<'gc, T>> {
         if self.is::<T>() {
             Some(unsafe {
                 let rv = self.raw.value().unwrap_unchecked();
@@ -260,6 +251,17 @@ impl<'gc> Value<'gc> {
         }
     }
 
+    #[inline]
+    pub(crate) fn as_num(self) -> Option<NixNum> {
+        if let Some(i) = self.as_inline::<i32>() {
+            Some(NixNum::Int(i as i64))
+        } else if let Some(gc_i) = self.as_gc::<i64>() {
+            Some(NixNum::Int(*gc_i))
+        } else {
+            self.as_float().map(NixNum::Float)
+        }
+    }
+
     #[inline]
     pub(crate) fn restrict(self) -> Option<StrictValue<'gc>> {
         if !self.is::<Thunk<'gc>>() {
@@ -270,88 +272,50 @@ impl<'gc> Value<'gc> {
     }
 }
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Default)]
 #[repr(transparent)]
-pub(crate) struct StaticValue {
-    raw: RawBox,
-}
+pub struct StaticValue(Value<'static>);
 
-impl Default for StaticValue {
-    #[inline(always)]
-    fn default() -> Self {
-        Self::new_inline(Null)
-    }
-}
-
-impl From<StaticValue> for Value<'_> {
+impl<'gc> From<StaticValue> for Value<'gc> {
     #[inline]
     fn from(value: StaticValue) -> Self {
-        Self {
-            raw: value.raw,
-            _marker: PhantomData,
-        }
+        // SAFETY: StaticValue is guaranteed to not contain any `Gc`.
+        unsafe { std::mem::transmute::<Value<'static>, Value<'gc>>(value.0) }
     }
 }
 
 impl StaticValue {
-    #[inline(always)]
-    fn from_raw_value(rv: RawValue) -> Self {
-        Self {
-            raw: RawBox::from_value(rv),
-        }
-    }
-
     #[inline]
-    pub(crate) fn to_bits(self) -> u64 {
-        self.raw.to_bits()
+    pub fn new_float(val: f64) -> Self {
+        Self(Value::new_float(val))
     }
-
     #[inline]
-    pub(crate) fn new_float(val: f64) -> Self {
-        Self {
-            raw: RawBox::from_float(val),
+    pub fn new_inline<T: InlineStorable>(val: T) -> Self {
+        Self(Value::new_inline(val))
     }
-    }
-
     #[inline]
-    pub(crate) fn new_inline<T: InlineStorable>(val: T) -> Self {
-        Self::from_raw_value(RawValue::store(
-            unsafe { RawTag::new_unchecked(T::TAG.0, T::TAG.1) },
-            val,
-        ))
+    pub fn new_primop(id: BuiltinId, arity: u8) -> Self {
+        Self(Value::new_inline(PrimOp { id, arity }))
     }
-
     #[inline]
-    pub(crate) fn is_float(&self) -> bool {
-        self.raw.is_float()
+    pub fn is_float(self) -> bool {
+        self.0.is_float()
     }
-
     #[inline]
-    pub(crate) fn is<T: InlineStorable>(&self) -> bool {
-        self.tag() == Some(T::TAG)
+    pub fn is<T: InlineStorable>(self) -> bool {
+        self.0.is::<T>()
     }
-
     #[inline]
-    pub(crate) fn as_float(&self) -> Option<f64> {
-        self.raw.float().copied()
+    pub fn as_float(self) -> Option<f64> {
+        self.0.as_float()
     }
-
     #[inline]
-    pub(crate) fn as_inline<T: InlineStorable>(&self) -> Option<T> {
-        if self.is::<T>() {
-            Some(unsafe {
-                let rv = self.raw.value().unwrap_unchecked();
-                T::from_val(rv)
-            })
-        } else {
-            None
+    pub fn as_inline<T: InlineStorable>(self) -> Option<T> {
+        self.0.as_inline::<T>()
     }
-    }
-
-    /// Returns the `(negative, val)` tag, or `None` for a float.
-    #[inline(always)]
-    fn tag(&self) -> Option<(bool, u8)> {
-        self.raw.tag().map(|t| t.neg_val())
+    #[inline]
+    pub fn to_bits(self) -> u64 {
+        self.0.raw.to_bits()
     }
 }
 
@@ -420,7 +384,7 @@ impl<'gc> Deref for AttrSet<'gc> {
 }
 
 impl<'gc> AttrSet<'gc> {
-    pub(crate) unsafe fn from_sorted_unchecked(
+    pub(crate) fn from_sorted_unchecked(
         entries: SmallVec<[(StringId, Value<'gc>); 4]>,
     ) -> Self {
         debug_assert!(entries.is_sorted_by_key(|(key, _)| *key));
@@ -492,7 +456,8 @@ pub(crate) type Thunk<'gc> = RefLock<ThunkState<'gc>>;
 pub(crate) enum ThunkState<'gc> {
     Pending {
         ip: usize,
-        env: Gc<'gc, RefLock<Env<'gc>>>,
+        env: GcEnv<'gc>,
+        with_env: Option<GcWithEnv<'gc>>,
     },
     Apply {
         func: Value<'gc>,
@@ -506,8 +471,17 @@ pub(crate) enum ThunkState<'gc> {
 #[collect(no_drop)]
 pub(crate) struct Env<'gc> {
     pub(crate) locals: SmallVec<[Value<'gc>; 4]>,
-    pub(crate) prev: Option<Gc<'gc, RefLock<Env<'gc>>>>,
+    pub(crate) prev: Option<GcEnv<'gc>>,
 }
+pub(crate) type GcEnv<'gc> = GcRefLock<'gc, Env<'gc>>;
+
+#[derive(Collect, Debug)]
+#[collect(no_drop)]
+pub(crate) struct WithEnv<'gc> {
+    pub(crate) env: Value<'gc>,
+    pub(crate) prev: Option<GcWithEnv<'gc>>,
+}
+pub(crate) type GcWithEnv<'gc> = Gc<'gc, WithEnv<'gc>>;
 
 impl<'gc> Env<'gc> {
     pub(crate) fn empty() -> Self {

fix/Cargo.toml

@@ -6,20 +6,9 @@ edition = "2024"
 [dependencies]
 mimalloc = "0.1"
 
-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 = "17.0"
+rustyline = "18.0"
 
 # CLI
 clap = { version = "4", features = ["derive"] }
@@ -28,67 +17,32 @@ clap = { version = "4", features = ["derive"] }
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 
-derive_more = { version = "2", features = ["full"] }
+# Error Reporting
 thiserror = "2"
 miette = { version = "7.4", features = ["fancy"] }
 
-hashbrown = "0.16"
-string-interner = "0.19"
-bumpalo = { version = "3.20", features = [
-    "allocator-api2",
-    "boxed",
-    "collections",
-] }
+# Data Structure
+hashbrown = { workspace = true }
+smallvec = { workspace = true }
+string-interner = { workspace = true }
 
-rust-embed = "8.11"
+# Memory Management
+bumpalo = { workspace = true }
 
-regex = "1.11"
+rnix = { workspace = true }
 
-nix-nar = "0.3"
-sha2 = "0.10"
-sha1 = "0.10"
-md5 = "0.8"
-hex = "0.4"
+ere = { workspace = true }
+ghost-cell = { workspace = true }
 
-base64 = "0.22"
-
-reqwest = { version = "0.13", features = [
-    "blocking",
-    "rustls",
-], default-features = false }
-tar = "0.4"
-flate2 = "1.0"
-xz2 = "0.1"
-bzip2 = "0.6"
-serde = { version = "1.0", features = ["derive"] }
-serde_json = "1.0"
-# spec 1.0.0
-toml = "=0.9.9"
-dirs = "6.0"
-tempfile = "3.24"
-rusqlite = { version = "0.38", features = ["bundled"] }
-
-rnix = "0.14"
-rowan = "0.16"
-
-ere = "0.2.4"
-num_enum = "0.7.5"
-tap = "1.0.1"
-
-ghost-cell = "0.2"
-colored = "3.1"
-sptr = "0.3"
-sealed = "0.6"
-small-map = "0.1"
-smallvec = "1.15"
-
-[dependencies.gc-arena]
-git = "https://github.com/kyren/gc-arena"
-rev = "75671ae03f53718357b741ed4027560f14e90836"
-features = ["allocator-api2", "hashbrown", "smallvec"]
+fix-common = { path = "../fix-common" }
+fix-codegen = { path = "../fix-codegen" }
+fix-error = { path = "../fix-error" }
+fix-ir = { path = "../fix-ir" }
+fix-vm = { path = "../fix-vm" }
 
 [dev-dependencies]
 criterion = { version = "0.8", features = ["html_reports"] }
+tempfile = "3.24"
 test-log = { version = "0.2", features = ["trace"] }
 
 [[bench]]

fix/benches/utils.rs

@@ -1,18 +1,15 @@
 #![allow(dead_code)]
 
-use fix::error::{Result, Source};
-use fix::runtime::Runtime;
-use fix::value::Value;
+use fix::Evaluator;
+use fix_common::Value;
+use fix_error::{Result, Source};
 
 pub fn eval(expr: &str) -> Value {
-    Runtime::new()
-        .unwrap()
+    Evaluator::new()
         .eval(Source::new_eval(expr.into()).unwrap())
         .unwrap()
 }
 
 pub fn eval_result(expr: &str) -> Result<Value> {
-    Runtime::new()
-        .unwrap()
-        .eval(Source::new_eval(expr.into()).unwrap())
+    Evaluator::new().eval(Source::new_eval(expr.into()).unwrap())
 }

fix/src/disassembler.rs

@@ -1,369 +0,0 @@
-use std::fmt::Write;
-
-use colored::Colorize;
-use num_enum::TryFromPrimitive;
-
-use crate::codegen::{InstructionPtr, Op};
-
-pub(crate) trait DisassemblerContext {
-    fn lookup_string(&self, id: u32) -> &str;
-    fn get_code(&self) -> &[u8];
-}
-
-pub(crate) struct Disassembler<'a, Ctx> {
-    code: &'a [u8],
-    ctx: &'a Ctx,
-    pc: usize,
-}
-
-impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
-    pub fn new(ip: InstructionPtr, ctx: &'a Ctx) -> Self {
-        Self {
-            code: ctx.get_code(),
-            ctx,
-            pc: ip.0,
-        }
-    }
-
-    fn read_u8(&mut self) -> u8 {
-        let b = self.code[self.pc];
-        self.pc += 1;
-        b
-    }
-
-    fn read_u16(&mut self) -> u16 {
-        let bytes = self.code[self.pc..self.pc + 2]
-            .try_into()
-            .expect("no enough bytes");
-        self.pc += 2;
-        u16::from_le_bytes(bytes)
-    }
-
-    fn read_u32(&mut self) -> u32 {
-        let bytes = self.code[self.pc..self.pc + 4]
-            .try_into()
-            .expect("no enough bytes");
-        self.pc += 4;
-        u32::from_le_bytes(bytes)
-    }
-
-    fn read_i32(&mut self) -> i32 {
-        let bytes = self.code[self.pc..self.pc + 4]
-            .try_into()
-            .expect("no enough bytes");
-        self.pc += 4;
-        i32::from_le_bytes(bytes)
-    }
-
-    fn read_i64(&mut self) -> i64 {
-        let bytes = self.code[self.pc..self.pc + 8]
-            .try_into()
-            .expect("no enough bytes");
-        self.pc += 8;
-        i64::from_le_bytes(bytes)
-    }
-
-    fn read_f64(&mut self) -> f64 {
-        let bytes = self.code[self.pc..self.pc + 8]
-            .try_into()
-            .expect("no enough bytes");
-        self.pc += 8;
-        f64::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.pc < self.code.len() {
-            let start_pos = self.pc;
-            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.pc];
-            let mut chunks = bytes_slice.chunks(4);
-
-            let first_chunk = chunks.next().unwrap_or(&[]);
-            let bytes_str = {
-                let mut temp = format!("{:02x}", self.code[start_pos]);
-                for b in first_chunk {
-                    let _ = write!(&mut temp, " {:02x}", b);
-                }
-                temp
-            };
-
-            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);
-            }
-
-            for chunk in chunks {
-                let bytes_str = {
-                    let mut temp = String::from("  ");
-                    for b in chunk {
-                        let _ = write!(&mut temp, " {:02x}", b);
-                    }
-                    temp
-                };
-
-                let extra_width = if start_pos > 0 {
-                    start_pos.ilog2() >> 4
-                } else {
-                    0
-                };
-
-                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::PushSmi => {
-                let val = self.read_i32();
-                ("PushSmi", format!("{}", val))
-            }
-            Op::PushBigInt => {
-                let val = self.read_i64();
-                ("PushBigInt", format!("{}", val))
-            }
-            Op::PushFloat => {
-                let val = self.read_f64();
-                ("PushFloat", format!("{}", val))
-            }
-            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();
-                ("MakeThunk", format!("-> {:04x}", offset))
-            }
-            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::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::MakeEmptyList => ("MakeEmptyList", String::new()),
-
-            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::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 id = self.read_u8();
-                ("LoadBuiltin", format!("id={}", id))
-            }
-            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()),
-        }
-    }
-}

fix/src/lib.rs

@@ -1,22 +1,555 @@
 #![warn(clippy::unwrap_used)]
 #![allow(dead_code)]
 
-mod boxing;
-pub mod error;
-pub mod logging;
-pub mod runtime;
-pub mod value;
+use bumpalo::Bump;
+use fix_codegen::{BytecodeContext, InstructionPtr};
+use fix_common::{StringId, Symbol};
+use fix_error::{Error, Result, Source};
+use fix_ir::downgrade::{Downgrade as _, DowngradeContext};
+use fix_ir::{Ir, IrRef, RawIrRef, ThunkId};
+use fix_vm::{ForceMode, StaticValue, Vm, VmContext};
+use ghost_cell::{GhostCell, GhostToken};
+use hashbrown::{HashMap, HashSet};
+use string_interner::DefaultStringInterner;
 
-mod codegen;
-mod derivation;
-mod disassembler;
-mod downgrade;
 // mod fetcher;
-mod ir;
-mod nar;
-mod nix_utils;
-mod store;
-mod string_context;
+// mod nar;
+// mod nix_utils;
+// mod store;
+// mod string_context;
+mod derivation;
+pub mod logging;
 
 #[global_allocator]
 static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
+
+pub struct Evaluator {
+    bytecode: Vec<u8>,
+    constants: Constants,
+    strings: DefaultStringInterner,
+
+    sources: Vec<Source>,
+    spans: Vec<(usize, rnix::TextRange)>,
+    // FIXME: remove?
+    thunk_count: usize,
+
+    global_env: HashMap<StringId, Ir<'static, RawIrRef<'static>>>,
+}
+
+impl Default for Evaluator {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Evaluator {
+    pub fn new() -> Self {
+        let mut strings = DefaultStringInterner::new();
+        let global_env = fix_ir::new_global_env(&mut strings);
+        Self {
+            sources: Vec::new(),
+            spans: Vec::new(),
+            strings,
+            thunk_count: 0,
+            bytecode: Vec::new(),
+            constants: Constants::default(),
+
+            global_env,
+        }
+    }
+
+    pub fn eval(&mut self, source: Source) -> Result<fix_common::Value> {
+        self.do_eval(source, None, ForceMode::AsIs)
+    }
+
+    pub fn eval_shallow(&mut self, source: Source) -> Result<fix_common::Value> {
+        self.do_eval(source, None, ForceMode::Shallow)
+    }
+
+    pub fn eval_deep(&mut self, source: Source) -> Result<fix_common::Value> {
+        self.do_eval(source, None, ForceMode::Deep)
+    }
+
+    pub fn eval_repl(
+        &mut self,
+        source: Source,
+        scope: &HashSet<StringId>,
+    ) -> Result<fix_common::Value> {
+        self.do_eval(source, Some(Scope::Repl(scope)), ForceMode::Shallow)
+    }
+
+    fn do_eval<'ctx>(
+        &'ctx mut self,
+        source: Source,
+        extra_scope: Option<Scope<'ctx>>,
+        force_mode: ForceMode,
+    ) -> Result<fix_common::Value> {
+        let root = self.downgrade(source, extra_scope)?;
+        let ip = fix_codegen::compile_bytecode(root.as_ref(), self);
+        let vm = Vm::new(self, ip, force_mode);
+        vm.run()
+    }
+
+    pub fn add_binding(
+        &mut self,
+        _ident: &str,
+        _expr: &str,
+        _scope: &mut HashSet<StringId>,
+    ) -> Result<fix_common::Value> {
+        todo!()
+    }
+
+    pub fn compile_bytecode(&mut self, source: Source) -> Result<InstructionPtr> {
+        let root = self.downgrade(source, None)?;
+        let ip = fix_codegen::compile_bytecode(root.as_ref(), self);
+        Ok(ip)
+    }
+
+    fn downgrade_ctx<'a, 'bump, 'id>(
+        &'a mut self,
+        bump: &'bump Bump,
+        token: GhostToken<'id>,
+        extra_scope: Option<Scope<'a>>,
+    ) -> DowngradeCtx<'a, 'id, 'bump> {
+        let Self {
+            global_env,
+            sources,
+            thunk_count,
+            strings,
+            ..
+        } = self;
+        DowngradeCtx {
+            bump,
+            token,
+            strings,
+            source: sources.last().expect("no current source").clone(),
+            scopes: [Scope::Global(global_env)]
+                .into_iter()
+                .chain(extra_scope)
+                .collect(),
+            with_scope_count: 0,
+            arg_count: 0,
+            thunk_count,
+            thunk_scopes: vec![ThunkScope::new_in(bump)],
+        }
+    }
+
+    fn downgrade<'a>(
+        &'a mut self,
+        source: Source,
+        extra_scope: Option<Scope<'a>>,
+    ) -> Result<OwnedIr> {
+        tracing::debug!("Parsing Nix expression");
+
+        self.sources.push(source.clone());
+
+        let root = rnix::Root::parse(&source.src);
+        handle_parse_error(root.errors(), source).map_or(Ok(()), Err)?;
+
+        tracing::debug!("Downgrading Nix expression");
+        let expr = root
+            .tree()
+            .expr()
+            .ok_or_else(|| Error::parse_error("unexpected EOF".into()))?;
+        let bump = Bump::new();
+        GhostToken::new(|token| {
+            let ir = self
+                .downgrade_ctx(&bump, token, extra_scope)
+                .downgrade_toplevel(expr)?;
+            let ir = unsafe { std::mem::transmute::<RawIrRef<'_>, RawIrRef<'static>>(ir) };
+            Ok(OwnedIr { _bump: bump, ir })
+        })
+    }
+}
+
+impl VmContext for &mut Evaluator {
+    fn intern_string(&mut self, s: impl AsRef<str>) -> StringId {
+        StringId(self.strings.get_or_intern(s))
+    }
+    fn resolve_string(&self, id: StringId) -> &str {
+        #[allow(clippy::unwrap_used)]
+        self.strings.resolve(id.0).unwrap()
+    }
+    fn bytecode(&self) -> &[u8] {
+        &self.bytecode
+    }
+    fn get_const(&self, id: u32) -> StaticValue {
+        #[allow(clippy::unwrap_used)]
+        self.constants.get(id).unwrap()
+    }
+
+    fn compile(&mut self, _source: Source) {
+        todo!();
+    }
+}
+
+#[derive(Default)]
+struct Constants {
+    data: Vec<StaticValue>,
+    dedup: HashMap<u64, u32>,
+}
+
+impl Constants {
+    fn insert(&mut self, val: StaticValue) -> u32 {
+        let bits = val.to_bits();
+        *self.dedup.entry(bits).or_insert_with(|| {
+            let idx = self.data.len() as u32;
+            self.data.push(val);
+            idx
+        })
+    }
+
+    fn get(&self, id: u32) -> Option<StaticValue> {
+        self.data.get(id as usize).copied()
+    }
+}
+
+fn parse_error_span(error: &rnix::ParseError) -> Option<rnix::TextRange> {
+    use rnix::ParseError::*;
+    match error {
+        Unexpected(range)
+        | UnexpectedExtra(range)
+        | UnexpectedWanted(_, range, _)
+        | UnexpectedDoubleBind(range)
+        | DuplicatedArgs(range, _) => Some(*range),
+        _ => None,
+    }
+}
+
+fn handle_parse_error<'a>(
+    errors: impl IntoIterator<Item = &'a rnix::ParseError>,
+    source: Source,
+) -> Option<Box<Error>> {
+    for err in errors {
+        if let Some(span) = parse_error_span(err) {
+            return Some(
+                Error::parse_error(err.to_string())
+                    .with_source(source)
+                    .with_span(span),
+            );
+        }
+    }
+    None
+}
+
+struct DowngradeCtx<'ctx, 'id, 'ir> {
+    bump: &'ir Bump,
+    token: GhostToken<'id>,
+    strings: &'ctx mut DefaultStringInterner,
+    source: Source,
+    scopes: Vec<Scope<'ctx>>,
+    with_scope_count: u32,
+    arg_count: u32,
+    thunk_count: &'ctx mut usize,
+    thunk_scopes: Vec<ThunkScope<'id, 'ir>>,
+}
+
+fn should_thunk<'id>(ir: IrRef<'id, '_>, token: &GhostToken<'id>) -> bool {
+    !matches!(
+        ir.borrow(token),
+        Ir::Builtin(_)
+            | Ir::Builtins
+            | Ir::Int(_)
+            | Ir::Float(_)
+            | Ir::Bool(_)
+            | Ir::Null
+            | Ir::Str(_)
+            | Ir::Thunk(_)
+    )
+}
+
+impl<'ctx, 'id, 'ir> DowngradeCtx<'ctx, 'id, 'ir> {
+    fn new(
+        bump: &'ir Bump,
+        token: GhostToken<'id>,
+        symbols: &'ctx mut DefaultStringInterner,
+        global: &'ctx HashMap<StringId, Ir<'static, RawIrRef<'static>>>,
+        extra_scope: Option<Scope<'ctx>>,
+        thunk_count: &'ctx mut usize,
+        source: Source,
+    ) -> Self {
+        Self {
+            bump,
+            token,
+            strings: symbols,
+            source,
+            scopes: std::iter::once(Scope::Global(global))
+                .chain(extra_scope)
+                .collect(),
+            thunk_count,
+            arg_count: 0,
+            with_scope_count: 0,
+            thunk_scopes: vec![ThunkScope::new_in(bump)],
+        }
+    }
+}
+
+impl<'ctx: 'ir, 'id, 'ir> DowngradeContext<'id, 'ir> for DowngradeCtx<'ctx, 'id, 'ir> {
+    fn new_expr(&self, expr: Ir<'ir, IrRef<'id, 'ir>>) -> IrRef<'id, 'ir> {
+        IrRef::new(self.bump.alloc(GhostCell::new(expr)))
+    }
+
+    fn maybe_thunk(&mut self, ir: IrRef<'id, 'ir>) -> IrRef<'id, 'ir> {
+        if !should_thunk(ir, &self.token) {
+            return ir;
+        }
+
+        let id = ThunkId(*self.thunk_count);
+        *self.thunk_count = self.thunk_count.checked_add(1).expect("thunk id overflow");
+        self.thunk_scopes
+            .last_mut()
+            .expect("no active cache scope")
+            .add_binding(id, ir, &self.token);
+        IrRef::alloc(self.bump, Ir::Thunk(id))
+    }
+
+    fn new_sym(&mut self, sym: String) -> StringId {
+        StringId(self.strings.get_or_intern(sym))
+    }
+
+    fn get_sym(&self, id: StringId) -> Symbol<'_> {
+        self.strings.resolve(id.0).expect("no symbol found").into()
+    }
+
+    fn lookup(&self, sym: StringId, span: rnix::TextRange) -> Result<IrRef<'id, 'ir>> {
+        for scope in self.scopes.iter().rev() {
+            match scope {
+                &Scope::Global(global_scope) => {
+                    if let Some(expr) = global_scope.get(&sym) {
+                        let ir = match expr {
+                            Ir::Builtins => Ir::Builtins,
+                            Ir::Builtin(s) => Ir::Builtin(*s),
+                            Ir::Bool(b) => Ir::Bool(*b),
+                            Ir::Null => Ir::Null,
+                            _ => unreachable!("globals should only contain leaf IR nodes"),
+                        };
+                        return Ok(self.new_expr(ir));
+                    }
+                }
+                &Scope::Repl(repl_bindings) => {
+                    if repl_bindings.contains(&sym) {
+                        return Ok(self.new_expr(Ir::ReplBinding(sym)));
+                    }
+                }
+                Scope::ScopedImport(scoped_bindings) => {
+                    if scoped_bindings.contains(&sym) {
+                        return Ok(self.new_expr(Ir::ScopedImportBinding(sym)));
+                    }
+                }
+                Scope::Let(let_scope) => {
+                    if let Some(&expr) = let_scope.get(&sym) {
+                        return Ok(self.new_expr(Ir::Thunk(expr)));
+                    }
+                }
+                &Scope::Param {
+                    sym: param_sym,
+                    abs_layer,
+                } => {
+                    if param_sym == sym {
+                        return Ok(self.new_expr(Ir::Arg {
+                            layer: self.thunk_scopes.len() - abs_layer,
+                        }));
+                    }
+                }
+            }
+        }
+
+        if self.with_scope_count > 0 {
+            Ok(self.new_expr(Ir::WithLookup(sym)))
+        } else {
+            Err(Error::downgrade_error(
+                format!("'{}' not found", self.get_sym(sym)),
+                self.get_current_source(),
+                span,
+            ))
+        }
+    }
+
+    fn get_current_source(&self) -> Source {
+        self.source.clone()
+    }
+
+    fn with_let_scope<F, R>(&mut self, keys: &[StringId], f: F) -> Result<R>
+    where
+        F: FnOnce(&mut Self) -> Result<(bumpalo::collections::Vec<'ir, IrRef<'id, 'ir>>, R)>,
+    {
+        let base = *self.thunk_count;
+        *self.thunk_count = self
+            .thunk_count
+            .checked_add(keys.len())
+            .expect("thunk id overflow");
+        let iter = keys
+            .iter()
+            .enumerate()
+            .map(|(offset, &key)| (key, ThunkId(base + offset)));
+        self.scopes.push(Scope::Let(iter.collect()));
+        let (vals, ret) = {
+            let mut guard = ScopeGuard { ctx: self };
+            f(guard.as_ctx())?
+        };
+        assert_eq!(keys.len(), vals.len());
+        let scope = self.thunk_scopes.last_mut().expect("no active thunk scope");
+        scope.extend_bindings((base..base + keys.len()).map(ThunkId).zip(vals));
+        Ok(ret)
+    }
+
+    fn with_param_scope<F, R>(&mut self, sym: StringId, f: F) -> R
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        self.scopes.push(Scope::Param {
+            sym,
+            abs_layer: self.thunk_scopes.len(),
+        });
+        let mut guard = ScopeGuard { ctx: self };
+        f(guard.as_ctx())
+    }
+
+    fn with_with_scope<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        self.with_scope_count += 1;
+        let ret = f(self);
+        self.with_scope_count -= 1;
+        ret
+    }
+
+    fn with_thunk_scope<F, R>(
+        &mut self,
+        f: F,
+    ) -> (
+        R,
+        bumpalo::collections::Vec<'ir, (ThunkId, IrRef<'id, 'ir>)>,
+    )
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        self.thunk_scopes.push(ThunkScope::new_in(self.bump));
+        let ret = f(self);
+        (
+            ret,
+            self.thunk_scopes
+                .pop()
+                .expect("no thunk scope left???")
+                .bindings,
+        )
+    }
+
+    fn bump(&self) -> &'ir bumpalo::Bump {
+        self.bump
+    }
+}
+
+impl<'id, 'ir, 'ctx: 'ir> DowngradeCtx<'ctx, 'id, 'ir> {
+    fn downgrade_toplevel(mut self, root: rnix::ast::Expr) -> Result<RawIrRef<'ir>> {
+        let body = root.downgrade(&mut self)?;
+        let thunks = self
+            .thunk_scopes
+            .pop()
+            .expect("no thunk scope left???")
+            .bindings;
+        let ir = IrRef::alloc(self.bump, Ir::TopLevel { body, thunks });
+        Ok(ir.freeze(self.token))
+    }
+}
+
+struct ThunkScope<'id, 'ir> {
+    bindings: bumpalo::collections::Vec<'ir, (ThunkId, IrRef<'id, 'ir>)>,
+}
+
+impl<'id, 'ir> ThunkScope<'id, 'ir> {
+    fn new_in(bump: &'ir Bump) -> Self {
+        Self {
+            bindings: bumpalo::collections::Vec::new_in(bump),
+        }
+    }
+
+    fn add_binding(&mut self, id: ThunkId, ir: IrRef<'id, 'ir>, _token: &GhostToken<'id>) {
+        self.bindings.push((id, ir));
+    }
+
+    fn extend_bindings(&mut self, iter: impl IntoIterator<Item = (ThunkId, IrRef<'id, 'ir>)>) {
+        self.bindings.extend(iter);
+    }
+}
+
+enum Scope<'ctx> {
+    Global(&'ctx HashMap<StringId, Ir<'static, RawIrRef<'static>>>),
+    Repl(&'ctx HashSet<StringId>),
+    ScopedImport(HashSet<StringId>),
+    Let(HashMap<StringId, ThunkId>),
+    Param { sym: StringId, abs_layer: usize },
+}
+
+struct ScopeGuard<'a, 'ctx, 'id, 'ir> {
+    ctx: &'a mut DowngradeCtx<'ctx, 'id, 'ir>,
+}
+
+impl Drop for ScopeGuard<'_, '_, '_, '_> {
+    fn drop(&mut self) {
+        self.ctx.scopes.pop();
+    }
+}
+
+impl<'id, 'ir, 'ctx> ScopeGuard<'_, 'ctx, 'id, 'ir> {
+    fn as_ctx(&mut self) -> &mut DowngradeCtx<'ctx, 'id, 'ir> {
+        self.ctx
+    }
+}
+
+struct OwnedIr {
+    _bump: Bump,
+    ir: RawIrRef<'static>,
+}
+
+impl OwnedIr {
+    unsafe fn new(ir: RawIrRef<'_>, bump: Bump) -> Self {
+        Self {
+            _bump: bump,
+            ir: unsafe { std::mem::transmute::<RawIrRef<'_>, RawIrRef<'static>>(ir) },
+        }
+    }
+
+    fn as_ref(&self) -> RawIrRef<'_> {
+        self.ir
+    }
+}
+
+impl BytecodeContext for Evaluator {
+    fn intern_string(&mut self, s: &str) -> StringId {
+        StringId(self.strings.get_or_intern(s))
+    }
+
+    fn register_span(&mut self, range: rnix::TextRange) -> u32 {
+        let id = self.spans.len();
+        let source_id = self
+            .sources
+            .len()
+            .checked_sub(1)
+            .expect("current_source not set");
+        self.spans.push((source_id, range));
+        id as u32
+    }
+
+    fn get_code(&self) -> &[u8] {
+        &self.bytecode
+    }
+
+    fn get_code_mut(&mut self) -> &mut Vec<u8> {
+        &mut self.bytecode
+    }
+
+    fn add_constant(&mut self, val: fix_codegen::Const) -> u32 {
+        use fix_codegen::Const::*;
+        let val = match val {
+            Smi(x) => StaticValue::new_inline(x),
+            Float(x) => StaticValue::new_float(x),
+            Bool(x) => StaticValue::new_inline(x),
+            String(x) => StaticValue::new_inline(x),
+            PrimOp { id, arity } => StaticValue::new_primop(id, arity),
+            Null => StaticValue::default(),
+        };
+        self.constants.insert(val)
+    }
+}

fix/src/main.rs

@@ -3,8 +3,8 @@ use std::process::exit;
 
 use anyhow::Result;
 use clap::{Args, Parser, Subcommand};
-use fix::error::Source;
-use fix::runtime::Runtime;
+use fix::Evaluator;
+use fix_error::Source;
 use hashbrown::HashSet;
 use rustyline::DefaultEditor;
 use rustyline::error::ReadlineError;
@@ -40,7 +40,7 @@ struct ExprSource {
     file: Option<PathBuf>,
 }
 
-fn run_compile(runtime: &mut Runtime, src: ExprSource, silent: bool) -> Result<()> {
+fn run_compile(eval: &mut Evaluator, src: ExprSource, _silent: bool) -> Result<()> {
     let src = if let Some(expr) = src.expr {
         Source::new_eval(expr)?
     } else if let Some(file) = src.file {
@@ -48,11 +48,11 @@ fn run_compile(runtime: &mut Runtime, src: ExprSource, silent: bool) -> Result<(
     } else {
         unreachable!()
     };
-    match runtime.compile_bytecode(src) {
-        Ok(ip) => {
-            if !silent {
-                println!("{}", runtime.disassemble_colored(ip));
-            }
+    match eval.compile_bytecode(src) {
+        Ok(_ip) => {
+            // if !silent {
+            //     println!("{}", eval.disassemble_colored(ip));
+            // }
         }
         Err(err) => {
             eprintln!("{:?}", miette::Report::new(*err));
@@ -62,7 +62,7 @@ fn run_compile(runtime: &mut Runtime, src: ExprSource, silent: bool) -> Result<(
     Ok(())
 }
 
-fn run_eval(runtime: &mut Runtime, src: ExprSource) -> Result<()> {
+fn run_eval(eval: &mut Evaluator, src: ExprSource) -> Result<()> {
     let src = if let Some(expr) = src.expr {
         Source::new_eval(expr)?
     } else if let Some(file) = src.file {
@@ -70,7 +70,7 @@ fn run_eval(runtime: &mut Runtime, src: ExprSource) -> Result<()> {
     } else {
         unreachable!()
     };
-    match runtime.eval_deep(src) {
+    match eval.eval_deep(src) {
         Ok(value) => {
             println!("{}", value.display_compat());
         }
@@ -82,7 +82,7 @@ fn run_eval(runtime: &mut Runtime, src: ExprSource) -> Result<()> {
     Ok(())
 }
 
-fn run_repl(runtime: &mut Runtime) -> Result<()> {
+fn run_repl(eval: &mut Evaluator) -> 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]*(.*)$");
@@ -101,20 +101,20 @@ fn run_repl(runtime: &mut Runtime) -> Result<()> {
                             eprintln!("Error: missing expression after '='");
                             continue;
                         }
-                        match runtime.add_binding(ident, expr, &mut scope) {
+                        match eval.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 runtime.eval_repl(src, &scope) {
+                        match eval.eval_repl(src, &scope) {
                             Ok(value) => println!("{value}"),
                             Err(err) => eprintln!("{:?}", miette::Report::new(*err)),
                         }
                     }
                 } else {
                     let src = Source::new_repl(line)?;
-                    match runtime.eval_repl(src, &scope) {
+                    match eval.eval_repl(src, &scope) {
                         Ok(value) => println!("{value}"),
                         Err(err) => eprintln!("{:?}", miette::Report::new(*err)),
                     }
@@ -141,11 +141,11 @@ fn main() -> Result<()> {
 
     let cli = Cli::parse();
 
-    let mut runtime = Runtime::new()?;
+    let mut eval = Evaluator::new();
 
     match cli.command {
-        Command::Compile { source, silent } => run_compile(&mut runtime, source, silent),
-        Command::Eval { source } => run_eval(&mut runtime, source),
-        Command::Repl => run_repl(&mut runtime),
+        Command::Compile { source, silent } => run_compile(&mut eval, source, silent),
+        Command::Eval { source } => run_eval(&mut eval, source),
+        Command::Repl => run_repl(&mut eval),
     }
 }

fix/src/nar.rs

@@ -4,7 +4,7 @@ use std::path::Path;
 use nix_nar::Encoder;
 use sha2::{Digest, Sha256};
 
-use crate::error::{Error, Result};
+use fix_error::{Error, Result};
 
 pub fn compute_nar_hash(path: &Path) -> Result<[u8; 32]> {
     let mut hasher = Sha256::new();

fix/src/runtime.rs

@@ -1,559 +0,0 @@
-use bumpalo::Bump;
-use gc_arena::{Arena, Rootable};
-use ghost_cell::{GhostCell, GhostToken};
-use hashbrown::{HashMap, HashSet};
-use rnix::TextRange;
-use string_interner::symbol::SymbolU32;
-use string_interner::{DefaultStringInterner, Symbol as _};
-
-use crate::codegen::{BytecodeContext, InstructionPtr};
-use crate::disassembler::{Disassembler, DisassemblerContext};
-use crate::downgrade::{Downgrade as _, DowngradeContext};
-use crate::error::{Error, Result, Source};
-use crate::ir::{Ir, IrRef, RawIrRef, StringId, ThunkId};
-use crate::runtime::builtins::init_builtins;
-use crate::runtime::value::StaticValue;
-use crate::runtime::vm::{ForceMode, new_gc_root};
-use crate::store::{DaemonStore, StoreConfig};
-use crate::value::Symbol;
-
-mod builtins;
-mod stack;
-pub(crate) mod value;
-mod vm;
-pub(crate) use builtins::{BUILTINS, BuiltinId};
-use stack::Stack;
-use vm::{ErrorFrame, GcRoot};
-
-pub struct Runtime {
-    // global
-    sources: Vec<Source>,
-    spans: Vec<(usize, TextRange)>,
-    store: DaemonStore,
-    strings: DefaultStringInterner,
-    // FIXME: remove?
-    thunk_count: usize,
-    bytecode: Vec<u8>,
-    pub(crate) constants: Vec<StaticValue>,
-    constant_dedup: HashMap<u64, u32>,
-
-    // downgrade
-    global_env: HashMap<StringId, Ir<'static, RawIrRef<'static>>>,
-
-    // eval
-    pc: usize,
-    fuel: usize,
-    error_contexts: Stack<8192, ErrorFrame>,
-    arena: Arena<Rootable![GcRoot<'_>]>,
-    force_mode: ForceMode,
-}
-
-impl Runtime {
-    const DEFAULT_FUEL_AMOUNT: usize = 2048;
-
-    pub fn new() -> Result<Self> {
-        // HACK: what the heck...
-        let mut global_env = HashMap::new();
-        let mut strings = DefaultStringInterner::new();
-        let arena = Arena::new(|mc| {
-            let (root, env) = new_gc_root(mc, &mut strings);
-            global_env = env;
-            root
-        });
-
-        let config = StoreConfig::from_env();
-        let store = DaemonStore::connect(&config.daemon_socket)?;
-
-        Ok(Self {
-            sources: Vec::new(),
-            spans: Vec::new(),
-            store,
-            strings,
-            thunk_count: 0,
-            bytecode: Vec::new(),
-            constants: Vec::new(),
-            constant_dedup: HashMap::new(),
-
-            global_env,
-
-            pc: 0,
-            fuel: Self::DEFAULT_FUEL_AMOUNT,
-            error_contexts: Stack::new(),
-            arena,
-            force_mode: ForceMode::default(),
-        })
-    }
-
-    pub fn eval(&mut self, source: Source) -> Result<crate::value::Value> {
-        self.do_eval(source, None, ForceMode::AsIs)
-    }
-
-    pub fn eval_shallow(&mut self, source: Source) -> Result<crate::value::Value> {
-        self.do_eval(source, None, ForceMode::Shallow)
-    }
-
-    pub fn eval_deep(&mut self, source: Source) -> Result<crate::value::Value> {
-        self.do_eval(source, None, ForceMode::Deep)
-    }
-
-    pub fn eval_repl(
-        &mut self,
-        source: Source,
-        scope: &HashSet<StringId>,
-    ) -> Result<crate::value::Value> {
-        self.do_eval(source, Some(Scope::Repl(scope)), ForceMode::Shallow)
-    }
-
-    fn do_eval<'ctx>(
-        &'ctx mut self,
-        source: Source,
-        extra_scope: Option<Scope<'ctx>>,
-        force_mode: ForceMode,
-    ) -> Result<crate::value::Value> {
-        let root = self.downgrade(source, extra_scope)?;
-        let ip = crate::codegen::compile_bytecode(root.as_ref(), self);
-        self.run(ip, force_mode)
-    }
-
-    pub fn add_binding(
-        &mut self,
-        _ident: &str,
-        _expr: &str,
-        _scope: &mut HashSet<StringId>,
-    ) -> Result<crate::value::Value> {
-        todo!()
-    }
-
-    pub fn compile_bytecode(&mut self, source: Source) -> Result<InstructionPtr> {
-        let root = self.downgrade(source, None)?;
-        let ip = crate::codegen::compile_bytecode(root.as_ref(), self);
-        Ok(ip)
-    }
-
-    pub fn disassemble_colored(&mut self, ip: InstructionPtr) -> String {
-        Disassembler::new(ip, self).disassemble_colored()
-    }
-
-    pub fn disassemble(&mut self, ip: InstructionPtr) -> String {
-        Disassembler::new(ip, self).disassemble()
-    }
-
-    fn downgrade_ctx<'a, 'bump, 'id>(
-        &'a mut self,
-        bump: &'bump Bump,
-        token: GhostToken<'id>,
-        extra_scope: Option<Scope<'a>>,
-    ) -> DowngradeCtx<'a, 'id, 'bump> {
-        let Runtime {
-            global_env,
-            sources,
-            thunk_count,
-            strings,
-            ..
-        } = self;
-        DowngradeCtx {
-            bump,
-            token,
-            strings,
-            source: sources.last().expect("no current source").clone(),
-            scopes: [Scope::Global(global_env)]
-                .into_iter()
-                .chain(extra_scope)
-                .collect(),
-            with_scope_count: 0,
-            arg_count: 0,
-            thunk_count,
-            thunk_scopes: vec![ThunkScope::new_in(bump)],
-        }
-    }
-
-    fn downgrade<'a>(
-        &'a mut self,
-        source: Source,
-        extra_scope: Option<Scope<'a>>,
-    ) -> Result<OwnedIr> {
-        tracing::debug!("Parsing Nix expression");
-
-        self.sources.push(source.clone());
-
-        let root = rnix::Root::parse(&source.src);
-        handle_parse_error(root.errors(), source).map_or(Ok(()), Err)?;
-
-        tracing::debug!("Downgrading Nix expression");
-        let expr = root
-            .tree()
-            .expr()
-            .ok_or_else(|| Error::parse_error("unexpected EOF".into()))?;
-        let bump = Bump::new();
-        GhostToken::new(|token| {
-            let ir = self
-                .downgrade_ctx(&bump, token, extra_scope)
-                .downgrade_toplevel(expr)?;
-            let ir = unsafe { std::mem::transmute::<RawIrRef<'_>, RawIrRef<'static>>(ir) };
-            Ok(OwnedIr { _bump: bump, ir })
-        })
-    }
-}
-
-fn parse_error_span(error: &rnix::ParseError) -> Option<rnix::TextRange> {
-    use rnix::ParseError::*;
-    match error {
-        Unexpected(range)
-        | UnexpectedExtra(range)
-        | UnexpectedWanted(_, range, _)
-        | UnexpectedDoubleBind(range)
-        | DuplicatedArgs(range, _) => Some(*range),
-        _ => None,
-    }
-}
-
-fn handle_parse_error<'a>(
-    errors: impl IntoIterator<Item = &'a rnix::ParseError>,
-    source: Source,
-) -> Option<Box<Error>> {
-    for err in errors {
-        if let Some(span) = parse_error_span(err) {
-            return Some(
-                Error::parse_error(err.to_string())
-                    .with_source(source)
-                    .with_span(span),
-            );
-        }
-    }
-    None
-}
-
-struct DowngradeCtx<'ctx, 'id, 'ir> {
-    bump: &'ir Bump,
-    token: GhostToken<'id>,
-    strings: &'ctx mut DefaultStringInterner,
-    source: Source,
-    scopes: Vec<Scope<'ctx>>,
-    with_scope_count: u32,
-    arg_count: u32,
-    thunk_count: &'ctx mut usize,
-    thunk_scopes: Vec<ThunkScope<'id, 'ir>>,
-}
-
-fn should_thunk<'id>(ir: IrRef<'id, '_>, token: &GhostToken<'id>) -> bool {
-    !matches!(
-        ir.borrow(token),
-        Ir::Builtin(_)
-            | Ir::Builtins
-            | Ir::Int(_)
-            | Ir::Float(_)
-            | Ir::Bool(_)
-            | Ir::Null
-            | Ir::Str(_)
-            | Ir::Thunk(_)
-    )
-}
-
-impl<'ctx, 'id, 'ir> DowngradeCtx<'ctx, 'id, 'ir> {
-    fn new(
-        bump: &'ir Bump,
-        token: GhostToken<'id>,
-        symbols: &'ctx mut DefaultStringInterner,
-        global: &'ctx HashMap<StringId, Ir<'static, RawIrRef<'static>>>,
-        extra_scope: Option<Scope<'ctx>>,
-        thunk_count: &'ctx mut usize,
-        source: Source,
-    ) -> Self {
-        Self {
-            bump,
-            token,
-            strings: symbols,
-            source,
-            scopes: std::iter::once(Scope::Global(global))
-                .chain(extra_scope)
-                .collect(),
-            thunk_count,
-            arg_count: 0,
-            with_scope_count: 0,
-            thunk_scopes: vec![ThunkScope::new_in(bump)],
-        }
-    }
-}
-
-impl<'ctx: 'ir, 'id, 'ir> DowngradeContext<'id, 'ir> for DowngradeCtx<'ctx, 'id, 'ir> {
-    fn new_expr(&self, expr: Ir<'ir, IrRef<'id, 'ir>>) -> IrRef<'id, 'ir> {
-        IrRef::new(self.bump.alloc(GhostCell::new(expr)))
-    }
-
-    fn maybe_thunk(&mut self, ir: IrRef<'id, 'ir>) -> IrRef<'id, 'ir> {
-        if !should_thunk(ir, &self.token) {
-            return ir;
-        }
-
-        let id = ThunkId(*self.thunk_count);
-        *self.thunk_count = self.thunk_count.checked_add(1).expect("thunk id overflow");
-        self.thunk_scopes
-            .last_mut()
-            .expect("no active cache scope")
-            .add_binding(id, ir, &self.token);
-        IrRef::alloc(self.bump, Ir::Thunk(id))
-    }
-
-    fn new_sym(&mut self, sym: String) -> StringId {
-        StringId(self.strings.get_or_intern(sym))
-    }
-
-    fn get_sym(&self, id: StringId) -> Symbol<'_> {
-        self.strings.resolve(id.0).expect("no symbol found").into()
-    }
-
-    fn lookup(&self, sym: StringId, span: TextRange) -> Result<IrRef<'id, 'ir>> {
-        for scope in self.scopes.iter().rev() {
-            match scope {
-                &Scope::Global(global_scope) => {
-                    if let Some(expr) = global_scope.get(&sym) {
-                        let ir = match expr {
-                            Ir::Builtins => Ir::Builtins,
-                            Ir::Builtin(s) => Ir::Builtin(*s),
-                            Ir::Bool(b) => Ir::Bool(*b),
-                            Ir::Null => Ir::Null,
-                            _ => unreachable!("globals should only contain leaf IR nodes"),
-                        };
-                        return Ok(self.new_expr(ir));
-                    }
-                }
-                &Scope::Repl(repl_bindings) => {
-                    if repl_bindings.contains(&sym) {
-                        return Ok(self.new_expr(Ir::ReplBinding(sym)));
-                    }
-                }
-                Scope::ScopedImport(scoped_bindings) => {
-                    if scoped_bindings.contains(&sym) {
-                        return Ok(self.new_expr(Ir::ScopedImportBinding(sym)));
-                    }
-                }
-                Scope::Let(let_scope) => {
-                    if let Some(&expr) = let_scope.get(&sym) {
-                        return Ok(self.new_expr(Ir::Thunk(expr)));
-                    }
-                }
-                &Scope::Param {
-                    sym: param_sym,
-                    abs_layer,
-                } => {
-                    if param_sym == sym {
-                        return Ok(self.new_expr(Ir::Arg {
-                            layer: self.thunk_scopes.len() - abs_layer,
-                        }));
-                    }
-                }
-            }
-        }
-
-        if self.with_scope_count > 0 {
-            Ok(self.new_expr(Ir::WithLookup(sym)))
-        } else {
-            Err(Error::downgrade_error(
-                format!("'{}' not found", self.get_sym(sym)),
-                self.get_current_source(),
-                span,
-            ))
-        }
-    }
-
-    fn get_current_source(&self) -> Source {
-        self.source.clone()
-    }
-
-    fn with_let_scope<F, R>(&mut self, keys: &[StringId], f: F) -> Result<R>
-    where
-        F: FnOnce(&mut Self) -> Result<(bumpalo::collections::Vec<'ir, IrRef<'id, 'ir>>, R)>,
-    {
-        let base = *self.thunk_count;
-        *self.thunk_count = self
-            .thunk_count
-            .checked_add(keys.len())
-            .expect("thunk id overflow");
-        let iter = keys.iter().enumerate().map(|(offset, &key)| {
-            (
-                key,
-                ThunkId(unsafe { base.checked_add(offset).unwrap_unchecked() }),
-            )
-        });
-        self.scopes.push(Scope::Let(iter.collect()));
-        let (vals, ret) = {
-            let mut guard = ScopeGuard { ctx: self };
-            f(guard.as_ctx())?
-        };
-        assert_eq!(keys.len(), vals.len());
-        let scope = self.thunk_scopes.last_mut().expect("no active thunk scope");
-        scope.extend_bindings((base..base + keys.len()).map(ThunkId).zip(vals));
-        Ok(ret)
-    }
-
-    fn with_param_scope<F, R>(&mut self, sym: StringId, f: F) -> R
-    where
-        F: FnOnce(&mut Self) -> R,
-    {
-        self.scopes.push(Scope::Param {
-            sym,
-            abs_layer: self.thunk_scopes.len(),
-        });
-        let mut guard = ScopeGuard { ctx: self };
-        f(guard.as_ctx())
-    }
-
-    fn with_with_scope<F, R>(&mut self, f: F) -> R
-    where
-        F: FnOnce(&mut Self) -> R,
-    {
-        self.with_scope_count += 1;
-        let ret = f(self);
-        self.with_scope_count -= 1;
-        ret
-    }
-
-    fn with_thunk_scope<F, R>(
-        &mut self,
-        f: F,
-    ) -> (
-        R,
-        bumpalo::collections::Vec<'ir, (ThunkId, IrRef<'id, 'ir>)>,
-    )
-    where
-        F: FnOnce(&mut Self) -> R,
-    {
-        self.thunk_scopes.push(ThunkScope::new_in(self.bump));
-        let ret = f(self);
-        (
-            ret,
-            self.thunk_scopes
-                .pop()
-                .expect("no thunk scope left???")
-                .bindings,
-        )
-    }
-
-    fn bump(&self) -> &'ir bumpalo::Bump {
-        self.bump
-    }
-}
-
-impl<'id, 'ir, 'ctx: 'ir> DowngradeCtx<'ctx, 'id, 'ir> {
-    fn downgrade_toplevel(mut self, root: rnix::ast::Expr) -> Result<RawIrRef<'ir>> {
-        let body = root.downgrade(&mut self)?;
-        let thunks = self
-            .thunk_scopes
-            .pop()
-            .expect("no thunk scope left???")
-            .bindings;
-        let ir = IrRef::alloc(self.bump, Ir::TopLevel { body, thunks });
-        Ok(ir.freeze(self.token))
-    }
-}
-
-struct ThunkScope<'id, 'ir> {
-    bindings: bumpalo::collections::Vec<'ir, (ThunkId, IrRef<'id, 'ir>)>,
-}
-
-impl<'id, 'ir> ThunkScope<'id, 'ir> {
-    fn new_in(bump: &'ir Bump) -> Self {
-        Self {
-            bindings: bumpalo::collections::Vec::new_in(bump),
-        }
-    }
-
-    fn add_binding(&mut self, id: ThunkId, ir: IrRef<'id, 'ir>, _token: &GhostToken<'id>) {
-        self.bindings.push((id, ir));
-    }
-
-    fn extend_bindings(&mut self, iter: impl IntoIterator<Item = (ThunkId, IrRef<'id, 'ir>)>) {
-        self.bindings.extend(iter);
-    }
-}
-
-enum Scope<'ctx> {
-    Global(&'ctx HashMap<StringId, Ir<'static, RawIrRef<'static>>>),
-    Repl(&'ctx HashSet<StringId>),
-    ScopedImport(HashSet<StringId>),
-    Let(HashMap<StringId, ThunkId>),
-    Param { sym: StringId, abs_layer: usize },
-}
-
-struct ScopeGuard<'a, 'ctx, 'id, 'ir> {
-    ctx: &'a mut DowngradeCtx<'ctx, 'id, 'ir>,
-}
-
-impl Drop for ScopeGuard<'_, '_, '_, '_> {
-    fn drop(&mut self) {
-        self.ctx.scopes.pop();
-    }
-}
-
-impl<'id, 'ir, 'ctx> ScopeGuard<'_, 'ctx, 'id, 'ir> {
-    fn as_ctx(&mut self) -> &mut DowngradeCtx<'ctx, 'id, 'ir> {
-        self.ctx
-    }
-}
-
-struct OwnedIr {
-    _bump: Bump,
-    ir: RawIrRef<'static>,
-}
-
-impl OwnedIr {
-    unsafe fn new(ir: RawIrRef<'_>, bump: Bump) -> Self {
-        Self {
-            _bump: bump,
-            ir: unsafe { std::mem::transmute::<RawIrRef<'_>, RawIrRef<'static>>(ir) },
-        }
-    }
-
-    fn as_ref(&self) -> RawIrRef<'_> {
-        self.ir
-    }
-}
-
-impl BytecodeContext for Runtime {
-    fn intern_string(&mut self, s: &str) -> StringId {
-        StringId(self.strings.get_or_intern(s))
-    }
-
-    fn register_span(&mut self, range: TextRange) -> u32 {
-        let id = self.spans.len();
-        let source_id = self
-            .sources
-            .len()
-            .checked_sub(1)
-            .expect("current_source not set");
-        self.spans.push((source_id, range));
-        id as u32
-    }
-
-    fn get_code(&self) -> &[u8] {
-        &self.bytecode
-    }
-
-    fn get_code_mut(&mut self) -> &mut Vec<u8> {
-        &mut self.bytecode
-    }
-
-    fn add_constant(&mut self, val: StaticValue) -> u32 {
-        let bits = val.to_bits();
-        *self.constant_dedup.entry(bits).or_insert_with(|| {
-            let idx = self.constants.len() as u32;
-            self.constants.push(val);
-            idx
-        })
-    }
-}
-
-impl DisassemblerContext for Runtime {
-    fn lookup_string(&self, id: u32) -> &str {
-        self.strings
-            .resolve(SymbolU32::try_from_usize(id as usize).expect("invalid string id"))
-            .expect("string not found")
-    }
-    fn get_code(&self) -> &[u8] {
-        &self.bytecode
-    }
-}
-
-struct WellKnownSymbols {
-    // TODO:
-}

fix/src/runtime/builtins.rs

@@ -1,410 +0,0 @@
-use gc_arena::{Collect, Gc, Mutation, RefLock};
-use hashbrown::HashMap;
-use num_enum::TryFromPrimitive;
-use smallvec::SmallVec;
-use string_interner::DefaultStringInterner;
-use string_interner::symbol::SymbolU32;
-
-use super::value::*;
-use crate::ir::{Ir, RawIrRef, StringId};
-
-/// Generates both the BUILTINS const table and the BuiltinId enum
-/// from a single source of truth, preventing index desync.
-macro_rules! define_builtins {
-    ($(($name:literal, $variant:ident, $arity:expr)),* $(,)?) => {
-        /// Builtin function registry.
-        /// Array index IS the PrimOp id. (name, arity) pairs.
-        pub(crate) const BUILTINS: &[(&str, u8)] = &[
-            $(($name, $arity),)*
-        ];
-
-        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, TryFromPrimitive, Collect)]
-        #[repr(u8)]
-        #[collect(require_static)]
-        pub(crate) enum BuiltinId {
-            $($variant,)*
-        }
-    };
-}
-
-define_builtins! {
-    ("abort",                    Abort,                    1),
-    ("__add",                      Add,                      2),
-    ("__addErrorContext",          AddErrorContext,           2),
-    ("__all",                      All,                      2),
-    ("__any",                      Any,                      2),
-    ("__appendContext",            AppendContext,             2),
-    ("__attrNames",                AttrNames,                1),
-    ("__attrValues",               AttrValues,               1),
-    ("baseNameOf",               BaseNameOf,               1),
-    ("__bitAnd",                   BitAnd,                   2),
-    ("__bitOr",                    BitOr,                    2),
-    ("__bitXor",                   BitXor,                   2),
-    ("break",                    Break,                    1),
-    ("__catAttrs",                 CatAttrs,                 2),
-    ("__ceil",                     Ceil,                     1),
-    ("__compareVersions",          CompareVersions,          2),
-    ("__concatLists",              ConcatLists,              1),
-    ("__concatMap",                ConcatMap,                2),
-    ("__concatStringsSep",         ConcatStringsSep,         2),
-    ("__convertHash",              ConvertHash,              1),
-    ("__deepSeq",                  DeepSeq,                  2),
-    ("derivation",               Derivation,               1),
-    ("derivationStrict",         DerivationStrict,         1),
-    ("dirOf",                    DirOf,                    1),
-    ("__div",                      Div,                      2),
-    ("__elem",                     Elem,                     2),
-    ("__elemAt",                   ElemAt,                   2),
-    ("fetchGit",                 FetchGit,                 1),
-    ("fetchMercurial",           FetchMercurial,           1),
-    ("fetchTarball",             FetchTarball,             1),
-    ("fetchTree",                FetchTree,                1),
-    ("__fetchurl",                 FetchUrl,                 1),
-    ("__filter",                   Filter,                   2),
-    ("__filterSource",             FilterSource,             2),
-    ("__findFile",                 FindFile,                 2),
-    ("__floor",                    Floor,                    1),
-    ("__foldl'",                   FoldlStrict,              3),
-    ("__fromJSON",                 FromJSON,                 1),
-    ("fromTOML",                 FromTOML,                 1),
-    ("__functionArgs",             FunctionArgs,             1),
-    ("__genList",                  GenList,                  2),
-    ("__genericClosure",           GenericClosure,           1),
-    ("__getAttr",                  GetAttr,                  2),
-    ("__getContext",               GetContext,               1),
-    ("__getEnv",                   GetEnv,                   1),
-    ("__groupBy",                  GroupBy,                  2),
-    ("__hasAttr",                  HasAttr,                  2),
-    ("__hasContext",               HasContext,               1),
-    ("__hashFile",                 HashFile,                 2),
-    ("__hashString",               HashString,               2),
-    ("__head",                     Head,                     1),
-    ("import",                   Import,                   1),
-    ("__intersectAttrs",           IntersectAttrs,           2),
-    ("__isAttrs",                  IsAttrs,                  1),
-    ("__isBool",                   IsBool,                   1),
-    ("__isFloat",                  IsFloat,                  1),
-    ("__isFunction",               IsFunction,               1),
-    ("__isInt",                    IsInt,                    1),
-    ("__isList",                   IsList,                   1),
-    ("isNull",                   IsNull,                   1),
-    ("__isPath",                   IsPath,                   1),
-    ("__isString",                 IsString,                 1),
-    ("__length",                   Length,                   1),
-    ("__lessThan",                 LessThan,                 2),
-    ("__listToAttrs",              ListToAttrs,              1),
-    ("map",                      Map,                      2),
-    ("__mapAttrs",                 MapAttrs,                 2),
-    ("__match",                    Match,                    2),
-    ("__mul",                      Mul,                      2),
-    ("null",                     Null,                     0), // constant, not a function
-    ("__parseDrvName",             ParseDrvName,             1),
-    ("__partition",                Partition,                2),
-    ("__path",                     Path,                     1),
-    ("__pathExists",               PathExists,               1),
-    ("placeholder",              Placeholder,              1),
-    ("__readDir",                  ReadDir,                  1),
-    ("__readFile",                 ReadFile,                 1),
-    ("__readFileType",             ReadFileType,             1),
-    ("removeAttrs",              RemoveAttrs,              2),
-    ("__replaceStrings",           ReplaceStrings,           3),
-    ("scopedImport",             ScopedImport,             2),
-    ("__seq",                      Seq,                      2),
-    ("__sort",                     Sort,                     2),
-    ("__split",                    Split,                    2),
-    ("__splitVersion",             SplitVersion,             1),
-    ("__storePath",                StorePath,                1),
-    ("__stringLength",             StringLength,             1),
-    ("__sub",                      Sub,                      2),
-    ("__substring",                Substring,                3),
-    ("__tail",                     Tail,                     1),
-    ("throw",                    Throw,                    1),
-    ("__toFile",                   ToFile,                   2),
-    ("__toJSON",                   ToJSON,                   1),
-    ("__toPath",                   ToPath,                   1),
-    ("toString",                 ToString,                 1),
-    ("__toXML",                    ToXML,                    1),
-    ("__trace",                    Trace,                    2),
-    ("__tryEval",                  TryEval,                  1),
-    ("__typeOf",                   TypeOf,                   1),
-    ("__unsafeDiscardStringContext", UnsafeDiscardStringContext, 1),
-    ("__unsafeGetAttrPos",         UnsafeGetAttrPos,         2),
-    ("__warn",                     Warn,                     2),
-    ("__zipAttrsWith",             ZipAttrsWith,             2),
-}
-
-/// Names that need to be pre-interned for builtin implementations.
-const EXTRA_INTERN_NAMES: &[&str] = &[
-    "builtins",
-    "currentSystem",
-    "langVersion",
-    "nixVersion",
-    "storeDir",
-    "nixPath",
-    "true",
-    "false",
-    // typeOf return values
-    "int",
-    "float",
-    "bool",
-    "string",
-    "path",
-    "null",
-    "set",
-    "list",
-    "lambda",
-    // attrset keys used by builtins
-    "name",
-    "value",
-    "success",
-    "right",
-    "wrong",
-    "key",
-    "operator",
-    "startSet",
-    "__toString",
-    "outPath",
-    "__functor",
-    "drvPath",
-    "type",
-    "derivation",
-    "version",
-];
-
-/// Returns true if this builtin has lazy argument semantics
-/// (not all args should be forced before dispatch).
-pub(super) fn is_lazy_builtin(id: BuiltinId) -> bool {
-    matches!(
-        id,
-        BuiltinId::Seq
-            | BuiltinId::DeepSeq
-            | BuiltinId::Trace
-            | BuiltinId::Warn
-            | BuiltinId::TryEval
-            | BuiltinId::AddErrorContext
-            | BuiltinId::Break
-    )
-}
-
-/// Intern all builtin names and extra names needed at runtime.
-fn intern_all_builtins(interner: &mut DefaultStringInterner) {
-    for &(name, _) in BUILTINS {
-        interner.get_or_intern(name);
-    }
-    for &name in EXTRA_INTERN_NAMES {
-        interner.get_or_intern(name);
-    }
-}
-
-pub(super) fn init_builtins<'gc>(
-    mc: &Mutation<'gc>,
-    strings: &mut DefaultStringInterner,
-) -> (
-    HashMap<StringId, Ir<'static, RawIrRef<'static>>>,
-    Value<'gc>,
-) {
-    let mut global_env = HashMap::new();
-    let builtins_sym = StringId(strings.get_or_intern("builtins"));
-    global_env.insert(builtins_sym, Ir::Builtins);
-    let mut entries = SmallVec::with_capacity(BUILTINS.len());
-
-    for (idx, &(name, arity)) in BUILTINS.iter().enumerate() {
-        let id = BuiltinId::try_from_primitive(idx as u8).expect("infallible");
-        if let Some(local_name) = name.strip_prefix("__") {
-            // scoped builtins
-            let name = StringId(strings.get_or_intern(name));
-            let local_name = StringId(strings.get_or_intern(local_name));
-            global_env.insert(name, Ir::Builtin(id));
-            entries.push((local_name, Value::new_inline(PrimOp { id, arity })));
-        } else {
-            // global builtins
-            let name = StringId(strings.get_or_intern(name));
-            global_env.insert(name, Ir::Builtin(id));
-            entries.push((name, Value::new_inline(PrimOp { id, arity })));
-        }
-    }
-
-    let consts = [
-        (
-            "__currentSystem",
-            Ir::BuiltinConst(StringId(strings.get_or_intern("currentSystem"))),
-            // FIXME: detect currentSystem
-            Value::new_gc(Gc::new(mc, NixString::new("x86_64-linux"))),
-        ),
-        ("__langVersion", Ir::Int(6), Value::new_inline(6i32)),
-        (
-            "__nixVersion",
-            Ir::BuiltinConst(StringId(strings.get_or_intern("nixVersion"))),
-            Value::new_gc(Gc::new(mc, NixString::new("2.24.0"))),
-        ),
-        (
-            "__storeDir",
-            Ir::BuiltinConst(StringId(strings.get_or_intern("storeDir"))),
-            Value::new_gc(Gc::new(mc, NixString::new("/nix/store"))),
-        ),
-        (
-            "__nixPath",
-            Ir::BuiltinConst(StringId(strings.get_or_intern("nixPath"))),
-            // FIXME: get from config
-            Value::new_gc(Gc::new(
-                mc,
-                List {
-                    inner: SmallVec::new(),
-                },
-            )),
-        ),
-        ("null", Ir::Null, Value::new_inline(Null)),
-        ("true", Ir::Bool(true), Value::new_inline(true)),
-        ("false", Ir::Bool(false), Value::new_inline(false)),
-    ];
-
-    for (idx, &(name, arity)) in BUILTINS.iter().enumerate() {
-        let id = BuiltinId::try_from_primitive(idx as u8).expect("infallible");
-        if let Some(local_name) = name.strip_prefix("__") {
-            // scoped builtins
-            let name = StringId(strings.get_or_intern(name));
-            let local_name = StringId(strings.get_or_intern(local_name));
-            global_env.insert(name, Ir::Builtin(id));
-            entries.push((local_name, Value::new_inline(PrimOp { id, arity })));
-        } else {
-            // global builtins
-            let name = StringId(strings.get_or_intern(name));
-            global_env.insert(name, Ir::Builtin(id));
-            entries.push((name, Value::new_inline(PrimOp { id, arity })));
-        }
-    }
-    for (name, ir, val) in consts {
-        if let Some(local_name) = name.strip_prefix("__") {
-            let name = StringId(strings.get_or_intern(name));
-            let local_name = StringId(strings.get_or_intern(local_name));
-            global_env.insert(name, ir);
-            entries.push((local_name, val));
-        } else {
-            let name = StringId(strings.get_or_intern(name));
-            global_env.insert(name, ir);
-            entries.push((name, val));
-        }
-    }
-
-    // Self-reference thunk for builtins.builtins
-    let self_ref_thunk: Gc<'gc, Thunk<'gc>> = Gc::new(mc, RefLock::new(ThunkState::Blackhole));
-    let sym = strings.get_or_intern("builtins");
-    entries.push((StringId(sym), Value::new_gc(self_ref_thunk)));
-
-    entries.sort_by_key(|(k, _)| *k);
-
-    let builtins_set = Gc::new(mc, unsafe { AttrSet::from_sorted_unchecked(entries) });
-    let builtins_val = Value::new_gc(builtins_set);
-
-    (global_env, builtins_val)
-}
-
-pub(super) type PrimOpArgs<'gc> = [Value<'gc>; 3];
-pub(super) type PrimOpStrictArgs<'gc> = [StrictValue<'gc>; 3];
-
-#[allow(non_snake_case)]
-pub(super) struct WellKnownSymbols {
-    abort: SymbolU32,
-    add: SymbolU32,
-    addErrorContext: SymbolU32,
-    all: SymbolU32,
-    any: SymbolU32,
-    appendContext: SymbolU32,
-    attrNames: SymbolU32,
-    attrValues: SymbolU32,
-    baseNameOf: SymbolU32,
-    bitAnd: SymbolU32,
-    bitOr: SymbolU32,
-    bitXor: SymbolU32,
-    catAttrs: SymbolU32,
-    ceil: SymbolU32,
-    compareVersions: SymbolU32,
-    concatLists: SymbolU32,
-    concatMap: SymbolU32,
-    concatStringsSep: SymbolU32,
-    convertHash: SymbolU32,
-    deepSeq: SymbolU32,
-    derivation: SymbolU32,
-    derivationStrict: SymbolU32,
-    dirOf: SymbolU32,
-    div: SymbolU32,
-    elem: SymbolU32,
-    elemAt: SymbolU32,
-    fetchGit: SymbolU32,
-    fetchMercurial: SymbolU32,
-    fetchTarball: SymbolU32,
-    fetchTree: SymbolU32,
-    fetchurl: SymbolU32,
-    filter: SymbolU32,
-    filterSource: SymbolU32,
-    findFile: SymbolU32,
-    floor: SymbolU32,
-    foldl: SymbolU32,
-    fromJSON: SymbolU32,
-    fromTOML: SymbolU32,
-    functionArgs: SymbolU32,
-    genList: SymbolU32,
-    genericClosure: SymbolU32,
-    getAttr: SymbolU32,
-    getContext: SymbolU32,
-    getEnv: SymbolU32,
-    groupBy: SymbolU32,
-    hasAttr: SymbolU32,
-    hasContext: SymbolU32,
-    hashFile: SymbolU32,
-    hashString: SymbolU32,
-    head: SymbolU32,
-    import: SymbolU32,
-    intersectAttrs: SymbolU32,
-    isAttrs: SymbolU32,
-    isBool: SymbolU32,
-    isFloat: SymbolU32,
-    isFunction: SymbolU32,
-    isInt: SymbolU32,
-    isList: SymbolU32,
-    isNull: SymbolU32,
-    isPath: SymbolU32,
-    isString: SymbolU32,
-    length: SymbolU32,
-    lessThan: SymbolU32,
-    listToAttrs: SymbolU32,
-    map: SymbolU32,
-    mapAttrs: SymbolU32,
-    match_: SymbolU32,
-    mul: SymbolU32,
-    null: SymbolU32,
-    parseDrvName: SymbolU32,
-    partition: SymbolU32,
-    path: SymbolU32,
-    pathExists: SymbolU32,
-    placeholder: SymbolU32,
-    readDir: SymbolU32,
-    readFile: SymbolU32,
-    readFileType: SymbolU32,
-    removeAttrs: SymbolU32,
-    replaceStrings: SymbolU32,
-    scopedImport: SymbolU32,
-    seq: SymbolU32,
-    sort: SymbolU32,
-    split: SymbolU32,
-    splitVersion: SymbolU32,
-    storePath: SymbolU32,
-    stringLength: SymbolU32,
-    sub: SymbolU32,
-    substring: SymbolU32,
-    tail: SymbolU32,
-    throw: SymbolU32,
-    toFile: SymbolU32,
-    toJSON: SymbolU32,
-    toPath: SymbolU32,
-    toString: SymbolU32,
-    toXML: SymbolU32,
-    trace: SymbolU32,
-    tryEval: SymbolU32,
-    typeOf: SymbolU32,
-    unsafeDiscardStringContext: SymbolU32,
-    unsafeGetAttrPos: SymbolU32,
-    warn: SymbolU32,
-    zipAttrsWith: SymbolU32,
-    break_: SymbolU32,
-}

fix/src/runtime/corepkgs/derivation.nix

@@ -1,31 +0,0 @@
-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

fix/src/runtime/corepkgs/fetchurl.nix

@@ -1,76 +0,0 @@
-{
-  system ? "", # obsolete
-  url,
-  hash ? "", # an SRI hash
-
-  # Legacy hash specification
-  md5 ? "",
-  sha1 ? "",
-  sha256 ? "",
-  sha512 ? "",
-  outputHash ?
-    if hash != "" then
-      hash
-    else if sha512 != "" then
-      sha512
-    else if sha1 != "" then
-      sha1
-    else if md5 != "" then
-      md5
-    else
-      sha256,
-  outputHashAlgo ?
-    if hash != "" then
-      ""
-    else if sha512 != "" then
-      "sha512"
-    else if sha1 != "" then
-      "sha1"
-    else if md5 != "" then
-      "md5"
-    else
-      "sha256",
-
-  executable ? false,
-  unpack ? false,
-  name ? baseNameOf (toString url),
-  # still translates to __impure to trigger derivationStrict error checks.
-  impure ? false,
-}:
-
-derivation (
-  {
-    builder = "builtin:fetchurl";
-
-    # New-style output content requirements.
-    outputHashMode = if unpack || executable then "recursive" else "flat";
-
-    inherit
-      name
-      url
-      executable
-      unpack
-      ;
-
-    system = "builtin";
-
-    # No need to double the amount of network traffic
-    preferLocalBuild = true;
-
-    impureEnvVars = [
-      # We borrow these environment variables from the caller to allow
-      # easy proxy configuration.  This is impure, but a fixed-output
-      # derivation like fetchurl is allowed to do so since its result is
-      # by definition pure.
-      "http_proxy"
-      "https_proxy"
-      "ftp_proxy"
-      "all_proxy"
-      "no_proxy"
-    ];
-
-    # To make "nix-prefetch-url" work.
-    urls = [ url ];
-  }
-  // (if impure then { __impure = true; } else { inherit outputHashAlgo outputHash; })
-)

fix/tests/tests/derivation.rs

@@ -1,4 +1,4 @@
-use fix::value::Value;
+use fix_common::Value;
 
 use crate::utils::{eval_deep, eval_deep_result};
 

fix/tests/tests/io_operations.rs

@@ -1,6 +1,6 @@
-use fix::error::Source;
-use fix::runtime::Runtime;
-use fix::value::Value;
+use fix::Evaluator;
+use fix_common::Value;
+use fix_error::Source;
 
 use crate::utils::{eval, eval_result};
 
@@ -97,7 +97,7 @@ fn import_with_complex_dependency_graph() {
 
 #[test_log::test]
 fn path_with_file() {
-    let mut ctx = Runtime::new().unwrap();
+    let mut ctx = Evaluator::new();
     let temp_dir = tempfile::tempdir().unwrap();
     let test_file = temp_dir.path().join("test.txt");
     std::fs::write(&test_file, "Hello, World!").unwrap();
@@ -136,7 +136,7 @@ fn path_with_custom_name() {
 
 #[test_log::test]
 fn path_with_directory_recursive() {
-    let mut ctx = Runtime::new().unwrap();
+    let mut ctx = Evaluator::new();
     let temp_dir = tempfile::tempdir().unwrap();
     let test_dir = temp_dir.path().join("mydir");
     std::fs::create_dir_all(&test_dir).unwrap();
@@ -159,7 +159,7 @@ fn path_with_directory_recursive() {
 
 #[test_log::test]
 fn path_flat_with_file() {
-    let mut ctx = Runtime::new().unwrap();
+    let mut ctx = Evaluator::new();
     let temp_dir = tempfile::tempdir().unwrap();
     let test_file = temp_dir.path().join("flat.txt");
     std::fs::write(&test_file, "Flat content").unwrap();

fix/tests/tests/lang.rs

@@ -2,9 +2,9 @@
 
 use std::path::PathBuf;
 
-use fix::error::Source;
-use fix::runtime::Runtime;
-use fix::value::Value;
+use fix::Evaluator;
+use fix_common::Value;
+use fix_error::{Source, SourceType};
 
 fn get_lang_dir() -> PathBuf {
     PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("tests/tests/lang")
@@ -14,10 +14,10 @@ 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 mut ctx = Runtime::new().map_err(|e| e.to_string())?;
+    let mut ctx = Evaluator::new();
     let content = std::fs::read_to_string(&nix_path).unwrap();
     let source = Source {
-        ty: fix::error::SourceType::File(nix_path.into()),
+        ty: SourceType::File(nix_path.into()),
         src: content.into(),
     };
     ctx.eval_deep(source.clone())

fix/tests/tests/string_context.rs

@@ -1,5 +1,5 @@
-use fix::runtime::Runtime;
-use fix::value::Value;
+use fix::Evaluator;
+use fix_common::Value;
 
 use crate::utils::eval_result;
 
@@ -153,7 +153,7 @@ fn string_add_merges_context() {
 
 #[test_log::test]
 fn context_in_derivation_args() {
-    let mut rt = Runtime::new().unwrap();
+    let mut rt = Evaluator::new();
     let result = rt
         .eval(
             r#"
@@ -182,7 +182,7 @@ fn context_in_derivation_args() {
 
 #[test_log::test]
 fn context_in_derivation_env() {
-    let mut rt = Runtime::new().unwrap();
+    let mut rt = Evaluator::new();
     let result = rt
         .eval(
             r#"
@@ -224,7 +224,7 @@ fn tostring_preserves_context() {
 
 #[test_log::test]
 fn interpolation_derivation_returns_outpath() {
-    let mut rt = Runtime::new().unwrap();
+    let mut rt = Evaluator::new();
     let result = rt
         .eval(
             r#"

fix/tests/tests/utils.rs

@@ -1,38 +1,31 @@
 #![allow(dead_code)]
 
-use fix::error::{Result, Source};
-use fix::runtime::Runtime;
-use fix::value::Value;
+use fix::Evaluator;
+use fix_common::Value;
+use fix_error::{Result, Source};
 
 pub fn eval(expr: &str) -> Value {
-    Runtime::new()
-        .unwrap()
+    Evaluator::new()
         .eval(Source::new_eval(expr.into()).unwrap())
         .unwrap()
 }
 
 pub fn eval_shallow(expr: &str) -> Value {
-    Runtime::new()
-        .unwrap()
+    Evaluator::new()
         .eval_shallow(Source::new_eval(expr.into()).unwrap())
         .unwrap()
 }
 
 pub fn eval_deep(expr: &str) -> Value {
-    Runtime::new()
-        .unwrap()
+    Evaluator::new()
         .eval_deep(Source::new_eval(expr.into()).unwrap())
         .unwrap()
 }
 
 pub fn eval_deep_result(expr: &str) -> Result<Value> {
-    Runtime::new()
-        .unwrap()
-        .eval_deep(Source::new_eval(expr.into()).unwrap())
+    Evaluator::new().eval_deep(Source::new_eval(expr.into()).unwrap())
 }
 
 pub fn eval_result(expr: &str) -> Result<Value> {
-    Runtime::new()
-        .unwrap()
-        .eval(Source::new_eval(expr.into()).unwrap())
+    Evaluator::new().eval(Source::new_eval(expr.into()).unwrap())
 }