mirror of https://github.com/rust-lang/rust
33 lines
896 B
Rust
33 lines
896 B
Rust
//@ force-host
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//@ no-prefer-dynamic
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#![deny(unused)]
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#![crate_type = "proc-macro"]
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extern crate proc_macro;
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use proc_macro::*;
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#[proc_macro_attribute]
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pub fn duplicate(attr: TokenStream, item: TokenStream) -> TokenStream {
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let mut new_name = Some(attr.into_iter().nth(0).unwrap());
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let mut encountered_idents = 0;
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let input = item.to_string();
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let ret = item
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.into_iter()
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.map(move |token| match token {
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TokenTree::Ident(_) if encountered_idents == 1 => {
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encountered_idents += 1;
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new_name.take().unwrap()
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}
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TokenTree::Ident(_) => {
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encountered_idents += 1;
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token
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}
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_ => token,
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})
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.collect::<TokenStream>();
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let mut input_again = input.parse::<TokenStream>().unwrap();
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input_again.extend(ret);
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input_again
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}
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