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extern crate proc_macro;
use proc_macro::*;
#[proc_macro_attribute]
pub fn foo(attr: TokenStream, f: TokenStream) -> TokenStream {
let mut tokens = f.into_iter();
assert_eq!(tokens.next().unwrap().to_string(), "#");
let next_attr = match tokens.next().unwrap() {
TokenTree::Group(g) => g,
_ => panic!(),
};
let fn_tok = tokens.next().unwrap();
let ident_tok = tokens.next().unwrap();
let args_tok = tokens.next().unwrap();
let body = tokens.next().unwrap();
let new_body = attr.into_iter()
.chain(next_attr.stream().into_iter().skip(1));
let tokens = vec![
fn_tok,
ident_tok,
args_tok,
Group::new(Delimiter::Brace, new_body.collect()).into(),
].into_iter().collect::<TokenStream>();
println!("{}", tokens);
return tokens
}
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