mirror of https://github.com/rust-lang/rust
55 lines
1.7 KiB
Rust
55 lines
1.7 KiB
Rust
//@ force-host
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//@ no-prefer-dynamic
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#![crate_type = "proc-macro"]
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extern crate proc_macro;
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use proc_macro::{Ident, Group, TokenStream, TokenTree as Tt};
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// This constant has to be above the ALLOCATING_ALGO_THRESHOLD
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// constant in inherent_impls_overlap.rs
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const REPEAT_COUNT: u32 = 501;
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#[proc_macro]
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/// Repeats the input many times, while replacing idents
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/// named "IDENT" with "id_$v", where v is a counter.
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pub fn repeat_with_idents(input: TokenStream) -> TokenStream {
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let mut res = Vec::new();
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fn visit_stream(res: &mut Vec<Tt>, stream :TokenStream, v: u32) {
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let mut stream_iter = stream.into_iter();
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while let Some(tt) = stream_iter.next() {
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match tt {
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Tt::Group(group) => {
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let tt = Tt::Group(visit_group(group, v));
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res.push(tt);
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},
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Tt::Ident(id) => {
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let id = if &id.to_string() == "IDENT" {
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Ident::new(&format!("id_{}", v), id.span())
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} else {
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id
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};
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res.push(Tt::Ident(id));
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},
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Tt::Punct(p) => {
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res.push(Tt::Punct(p));
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},
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Tt::Literal(lit) => {
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res.push(Tt::Literal(lit));
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},
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}
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}
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}
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fn visit_group(group :Group, v: u32) -> Group {
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let mut res = Vec::new();
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visit_stream(&mut res, group.stream(), v);
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let stream = res.into_iter().collect();
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let delim = group.delimiter();
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Group::new(delim, stream)
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}
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for v in 0 .. REPEAT_COUNT {
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visit_stream(&mut res, input.clone(), v)
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}
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res.into_iter().collect()
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}
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