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extern crate proc_macro;
use proc_macro::{Ident, Punct, Spacing, Span, TokenStream, TokenTree};
use std::iter::once;
use std::time::Instant;
const N: u32 = 7000;
#[proc_macro]
pub fn bench(_input: TokenStream) -> TokenStream {
let start = Instant::now();
let mut string = String::new();
for _ in 0..N {
string += "core";
string += ":";
string += ":";
string += "option";
string += ":";
string += ":";
string += "Option";
string += ":";
string += ":";
string += "None";
string += ",";
}
string.parse::<TokenStream>().unwrap();
eprintln!("STRING: {} millis", start.elapsed().as_millis());
let start = Instant::now();
let span = Span::call_site();
let mut tokens = TokenStream::new();
for _ in 0..N {
// Similar to what is emitted by quote.
tokens.extend(once(TokenTree::Ident(Ident::new("core", span))));
tokens.extend(once(TokenTree::Punct(Punct::new(':', Spacing::Joint))));
tokens.extend(once(TokenTree::Punct(Punct::new(':', Spacing::Alone))));
tokens.extend(once(TokenTree::Ident(Ident::new("option", span))));
tokens.extend(once(TokenTree::Punct(Punct::new(':', Spacing::Joint))));
tokens.extend(once(TokenTree::Punct(Punct::new(':', Spacing::Alone))));
tokens.extend(once(TokenTree::Ident(Ident::new("Option", span))));
tokens.extend(once(TokenTree::Punct(Punct::new(':', Spacing::Joint))));
tokens.extend(once(TokenTree::Punct(Punct::new(':', Spacing::Alone))));
tokens.extend(once(TokenTree::Ident(Ident::new("None", span))));
tokens.extend(once(TokenTree::Punct(Punct::new(',', Spacing::Joint))));
}
eprintln!("TOKENSTREAM: {} millis", start.elapsed().as_millis());
TokenStream::new()
}
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