feat(ast_codegen): support for generate_derive marker. (#4728)

Follow-on after #4276, related to #4284.

crates/oxc_ast_macros/src/lib.rs

@@ -49,7 +49,7 @@ pub fn ast(_args: TokenStream, input: TokenStream) -> TokenStream {
 /// Does not generate any code.
 /// Only purpose is to allow using `#[scope]`, `#[visit]`, and other attrs in the AST node type defs.
 /// These "marker" attributes are used in codegen.
-#[proc_macro_derive(Ast, attributes(scope, visit, span, serde, tsify))]
+#[proc_macro_derive(Ast, attributes(scope, visit, span, serde, tsify, generate_derive))]
 pub fn ast_derive(_item: TokenStream) -> TokenStream {
  TokenStream::new()
 }

tasks/ast_codegen/src/schema/defs.rs

@@ -26,6 +26,15 @@ impl TypeDef {
  pub fn visitable(&self) -> bool {
  with_either!(self, it => it.visitable)
  }
+
+ pub fn generated_derives(&self) -> &Vec<String> {
+ with_either!(self, it => &it.generated_derives)
+ }
+
+ pub fn generates_derive(&self, derive: &str) -> bool {
+ let generated_derives = self.generated_derives();
+ generated_derives.iter().any(|it| it == derive)
+ }
 }
 
 #[derive(Debug, Serialize)]
@@ -41,6 +50,7 @@ pub struct StructDef {
  pub size_32: usize,
  pub align_32: usize,
  pub offsets_32: Option<Vec<usize>>,
+ pub generated_derives: Vec<String>,
  #[serde(skip)]
  pub markers: OuterMarkers,
 }
@@ -60,6 +70,7 @@ pub struct EnumDef {
  pub size_32: usize,
  pub align_32: usize,
  pub offsets_32: Option<Vec<usize>>,
+ pub generated_derives: Vec<String>,
 }
 
 impl EnumDef {

tasks/ast_codegen/src/schema/mod.rs

@@ -148,6 +148,8 @@ fn lower_ast_enum(it @ rust::Enum { item, meta }: &rust::Enum, ctx: &crate::Earl
  size_32,
  align_32,
  offsets_32,
+
+ generated_derives: parse_generate_derive(&item.attrs),
  }
 }
 
@@ -178,6 +180,8 @@ fn lower_ast_struct(
  align_32,
  offsets_32,
  markers: parse_outer_markers(&item.attrs).unwrap(),
+
+ generated_derives: parse_generate_derive(&item.attrs),
  }
 }
 
@@ -264,6 +268,23 @@ fn get_docs(attrs: &[syn::Attribute]) -> Vec<String> {
  .collect()
 }
 
+fn parse_generate_derive(attrs: &[syn::Attribute]) -> Vec<String> {
+ let mut derives = std::collections::HashSet::new();
+ for attr in attrs {
+ if !attr.path().is_ident("generate_derive") {
+ continue;
+ }
+
+ let args: syn::punctuated::Punctuated<syn::Ident, syn::Token![,]> =
+ attr.parse_args_with(syn::punctuated::Punctuated::parse_terminated).unwrap();
+
+ for arg in args {
+ derives.insert(arg.to_string());
+ }
+ }
+ Vec::from_iter(derives)
+}
+
 macro_rules! with_either {
  ($def:expr, $it:ident => $body:expr) => {
  match $def {