mirror of
https://github.com/fluencelabs/wasm-bindgen
synced 2025-05-11 13:29:43 +00:00
c35d6f4b0a
Reported in #1191 the fix requires us to get a bit creative I think. The general gist is that a block like this: #[wasm_bindgen] impl Foo { pub fn foo() {} } was previously expanded all in one go. Now, however, it's expanded into: impl Foo { #[__wasm_bindgen_class_marker(Foo = "Foo")] pub fn foo() {} } // goop generated by orginal #[wasm_bindgen] This method of expansion takes advantage of rustc's recursive expansion feature. It also allows us to expand `impl` blocks and allow inner items to not be fully expanded yet, such as still having `#[cfg]` attributes (like in the original bug report). We use theinternal `__wasm_bindgen_class_marker` to indicate that we're parsing an `ImplItemMethod` unconditionally, and then generation proceeds as usual. The only final catch is that when we're expanding in an `impl` block we have to generate tokens for the `Program` (wasm-bindgen injected goop like the custom section) inside the body of the function itself instead of next to it. Otherwise we'd get syntax errors inside of impl blocks! Closes #1191
35 lines
1.0 KiB
Rust
Executable File
35 lines
1.0 KiB
Rust
Executable File
#![doc(html_root_url = "https://docs.rs/wasm-bindgen-macro/0.2")]
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extern crate proc_macro;
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#[macro_use]
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extern crate quote;
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extern crate wasm_bindgen_macro_support as macro_support;
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use proc_macro::TokenStream;
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#[proc_macro_attribute]
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pub fn wasm_bindgen(attr: TokenStream, input: TokenStream) -> TokenStream {
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match macro_support::expand(attr.into(), input.into()) {
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Ok(tokens) => {
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if cfg!(feature = "xxx_debug_only_print_generated_code") {
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println!("{}", tokens);
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}
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tokens.into()
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}
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Err(diagnostic) => (quote! { #diagnostic }).into(),
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}
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}
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#[proc_macro_attribute]
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pub fn __wasm_bindgen_class_marker(attr: TokenStream, input: TokenStream) -> TokenStream {
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match macro_support::expand_class_marker(attr.into(), input.into()) {
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Ok(tokens) => {
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if cfg!(feature = "xxx_debug_only_print_generated_code") {
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println!("{}", tokens);
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}
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tokens.into()
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}
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Err(diagnostic) => (quote! { #diagnostic }).into(),
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}
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}
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