feat: init

nix-js-macros/src/ir.rs

@@ -0,0 +1,203 @@
+//! Implements the `ir!` procedural macro.
+//!
+//! This macro is designed to reduce the boilerplate associated with defining
+//! an Intermediate Representation (IR) that follows a specific pattern. It generates:
+//! 1. An enum representing the different kinds of IR nodes.
+//! 2. Structs for each of the variants that have fields.
+//! 3. `Ref` and `Mut` versions of the main enum for ergonomic pattern matching on references.
+//! 4. `From` implementations to easily convert from a struct variant (e.g., `BinOp`) to the main enum (`Ir::BinOp`).
+//! 5. A `To[IrName]` trait to provide a convenient `.to_ir()` method on the variant structs.
+
+use convert_case::{Case, Casing};
+use proc_macro::TokenStream;
+use quote::{format_ident, quote};
+use syn::{
+    FieldsNamed, Ident, Token, Type, parenthesized,
+    parse::{Parse, ParseStream, Result},
+    punctuated::Punctuated,
+    token,
+};
+
+/// Represents one of the variants passed to the `ir!` macro.
+pub enum VariantInput {
+    /// A unit-like variant, e.g., `Arg`.
+    Unit(Ident),
+    /// A tuple-like variant with one unnamed field, e.g., `ExprRef(ExprId)`.
+    Tuple(Ident, Type),
+    /// A struct-like variant with named fields, e.g., `BinOp { lhs: ExprId, rhs: ExprId, kind: BinOpKind }`.
+    Struct(Ident, FieldsNamed),
+}
+
+/// The top-level input for the `ir!` macro.
+pub struct MacroInput {
+    /// The name of the main IR enum to be generated (e.g., `Ir`).
+    pub base_name: Ident,
+    /// The list of variants for the enum.
+    pub variants: Punctuated<VariantInput, Token![,]>,
+}
+
+impl Parse for VariantInput {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let name: Ident = input.parse()?;
+
+        if input.peek(token::Paren) {
+            // Parse a tuple-like variant: `Variant(Type)`
+            let content;
+            parenthesized!(content in input);
+            let ty: Type = content.parse()?;
+
+            if !content.is_empty() {
+                return Err(content.error("Expected a single type inside parentheses"));
+            }
+
+            Ok(VariantInput::Tuple(name, ty))
+        } else if input.peek(token::Brace) {
+            // Parse a struct-like variant: `Variant { field: Type, ... }`
+            let fields: FieldsNamed = input.parse()?;
+            Ok(VariantInput::Struct(name, fields))
+        } else {
+            // Parse a unit-like variant: `Variant`
+            Ok(VariantInput::Unit(name))
+        }
+    }
+}
+
+impl Parse for MacroInput {
+    fn parse(input: ParseStream) -> Result<Self> {
+        // The macro input is expected to be: `IrName, Variant1, Variant2, ...`
+        let base_name = input.parse()?;
+        input.parse::<Token![,]>()?;
+        let variants = Punctuated::parse_terminated(input)?;
+
+        Ok(MacroInput {
+            base_name,
+            variants,
+        })
+    }
+}
+
+/// The implementation of the `ir!` macro.
+pub fn ir_impl(input: TokenStream) -> TokenStream {
+    let parsed_input = syn::parse_macro_input!(input as MacroInput);
+
+    let base_name = &parsed_input.base_name;
+    let ref_name = format_ident!("{}Ref", base_name);
+    let mut_name = format_ident!("{}Mut", base_name);
+    let to_trait_name = format_ident!("To{}", base_name);
+    let to_trait_fn_name = format_ident!("to_{}", base_name.to_string().to_case(Case::Snake));
+
+    let mut enum_variants = Vec::new();
+    let mut struct_defs = Vec::new();
+    let mut ref_variants = Vec::new();
+    let mut mut_variants = Vec::new();
+    let mut as_ref_arms = Vec::new();
+    let mut as_mut_arms = Vec::new();
+    let mut from_impls = Vec::new();
+    let mut to_trait_impls = Vec::new();
+
+    for variant in parsed_input.variants {
+        match variant {
+            VariantInput::Unit(name) => {
+                let inner_type = name.clone();
+                enum_variants.push(quote! { #name(#inner_type) });
+                ref_variants.push(quote! { #name(&'a #inner_type) });
+                mut_variants.push(quote! { #name(&'a mut #inner_type) });
+                as_ref_arms.push(quote! { Self::#name(inner) => #ref_name::#name(inner) });
+                as_mut_arms.push(quote! { Self::#name(inner) => #mut_name::#name(inner) });
+                from_impls.push(quote! {
+                    impl From<#inner_type> for #base_name {
+                        fn from(val: #inner_type) -> Self { #base_name::#name(val) }
+                    }
+                });
+                to_trait_impls.push(quote! {
+                    impl #to_trait_name for #name {
+                        fn #to_trait_fn_name(self) -> #base_name { #base_name::from(self) }
+                    }
+                });
+            }
+            VariantInput::Tuple(name, ty) => {
+                enum_variants.push(quote! { #name(#ty) });
+                ref_variants.push(quote! { #name(&'a #ty) });
+                mut_variants.push(quote! { #name(&'a mut #ty) });
+                as_ref_arms.push(quote! { Self::#name(inner) => #ref_name::#name(inner) });
+                as_mut_arms.push(quote! { Self::#name(inner) => #mut_name::#name(inner) });
+            }
+            VariantInput::Struct(name, fields) => {
+                let inner_type = name.clone();
+                struct_defs.push(quote! {
+                    #[derive(Debug)]
+                    pub struct #name #fields
+                });
+                enum_variants.push(quote! { #name(#inner_type) });
+                ref_variants.push(quote! { #name(&'a #inner_type) });
+                mut_variants.push(quote! { #name(&'a mut #inner_type) });
+                as_ref_arms.push(quote! { Self::#name(inner) => #ref_name::#name(inner) });
+                as_mut_arms.push(quote! { Self::#name(inner) => #mut_name::#name(inner) });
+                from_impls.push(quote! {
+                    impl From<#inner_type> for #base_name {
+                        fn from(val: #inner_type) -> Self { #base_name::#name(val) }
+                    }
+                });
+                to_trait_impls.push(quote! {
+                    impl #to_trait_name for #name {
+                        fn #to_trait_fn_name(self) -> #base_name { #base_name::from(self) }
+                    }
+                });
+            }
+        }
+    }
+
+    // Assemble the final generated code.
+    let expanded = quote! {
+        /// The main IR enum, generated by the `ir!` macro.
+        #[derive(Debug, IsVariant, Unwrap, TryUnwrap)]
+        pub enum #base_name {
+            #( #enum_variants ),*
+        }
+
+        // The struct definitions for the enum variants.
+        #( #struct_defs )*
+
+        /// An immutable reference version of the IR enum.
+        #[derive(Debug, IsVariant, Unwrap, TryUnwrap)]
+        pub enum #ref_name<'a> {
+            #( #ref_variants ),*
+        }
+
+        /// A mutable reference version of the IR enum.
+        #[derive(Debug, IsVariant, Unwrap, TryUnwrap)]
+        pub enum #mut_name<'a> {
+            #( #mut_variants ),*
+        }
+
+        impl #base_name {
+            /// Converts a `&Ir` into a `IrRef`.
+            pub fn as_ref(&self) -> #ref_name<'_> {
+                match self {
+                    #( #as_ref_arms ),*
+                }
+            }
+
+            /// Converts a `&mut Ir` into a `IrMut`.
+            pub fn as_mut(&mut self) -> #mut_name<'_> {
+                match self {
+                    #( #as_mut_arms ),*
+                }
+            }
+        }
+
+        // `From` implementations for converting variant structs into the main enum.
+        #( #from_impls )*
+
+        /// A trait for converting a variant struct into the main IR enum.
+        pub trait #to_trait_name {
+            /// Performs the conversion.
+            fn #to_trait_fn_name(self) -> #base_name;
+        }
+
+        // Implement the `ToIr` trait for each variant struct.
+        #( #to_trait_impls )*
+    };
+
+    TokenStream::from(expanded)
+}

nix-js-macros/src/lib.rs

@@ -0,0 +1,13 @@
+//! This crate provides procedural macros for the nixjit project.
+use proc_macro::TokenStream;
+
+mod ir;
+
+/// A procedural macro to reduce boilerplate when defining an Intermediate Representation (IR).
+///
+/// It generates an enum for the IR, along with `Ref` and `Mut` variants,
+/// `From` implementations, and a `ToIr` trait.
+#[proc_macro]
+pub fn ir(input: TokenStream) -> TokenStream {
+    ir::ir_impl(input)
+}