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#[macro_use]
extern crate pmutil;
extern crate proc_macro;
extern crate proc_macro2;
extern crate quote;
extern crate swc_macros_common;
extern crate syn;
use proc_macro::TokenStream;
use swc_macros_common::prelude::*;
#[proc_macro_attribute]
pub fn emitter(_attr: TokenStream, item: TokenStream) -> TokenStream {
let item = syn::parse(item).expect("failed to parse input as an item");
let item = expand(item);
print("emitter", item.dump())
}
fn expand(i: ImplItemMethod) -> ImplItemMethod {
let mtd_name = i.sig.ident.clone();
assert!(
format!("{}", i.sig.ident).starts_with("emit_"),
"#[emitter] methods should start with `emit_`"
);
let block = {
let node_type = {
i.sig
.decl
.inputs
.clone()
.into_iter()
.skip(1)
.next()
.and_then(|arg| match arg {
FnArg::Ignored(ty) | FnArg::Captured(ArgCaptured { ty, .. }) => Some(ty),
_ => None,
})
.map(|ty| {
match ty {
Type::Reference(TypeReference { elem, .. }) => *elem,
_ => panic!(
"Type of node parameter should be reference but got {}",
ty.dump()
),
}
})
.expect(
"#[emitter] methods should have signature of
fn (&mut self, node: Node) -> \
Result;
",
)
};
Quote::new_call_site()
.quote_with(smart_quote!(
Vars {
block: &i.block,
NodeType: &node_type,
mtd_name,
},
{
{
const _FOO: () = {
impl ::Node for NodeType {
fn emit_with(&self, e: &mut ::Emitter) -> Result {
e.mtd_name(self)
}
}
()
};
#[allow(unused_macros)]
macro_rules! __cur_emitter {
() => {
self
};
}
{
block
};
#[allow(unreachable_code)]
{
return Ok(());
}
}
}
))
.parse()
};
ImplItemMethod { block, ..i }
}