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// ignore-tidy-linelength
#![feature(proc_macro_quote)]
extern crate proc_macro;
use std::iter::FromIterator;
use std::str::FromStr;
use proc_macro::*;
#[proc_macro]
pub fn custom_quote(input: TokenStream) -> TokenStream {
let mut tokens: Vec<_> = input.into_iter().collect();
assert_eq!(tokens.len(), 1, "Unexpected input: {:?}", tokens);
match tokens.pop() {
Some(TokenTree::Ident(ident)) => {
assert_eq!(ident.to_string(), "my_ident");
let proc_macro_crate = TokenStream::from_str("::proc_macro").unwrap();
let quoted_span = proc_macro::quote_span(proc_macro_crate, ident.span());
let prefix = TokenStream::from_str(r#"let mut ident = proc_macro::Ident::new("my_ident", proc_macro::Span::call_site());"#).unwrap();
let set_span_method = TokenStream::from_str("ident.set_span").unwrap();
let set_span_arg = TokenStream::from(TokenTree::Group(Group::new(Delimiter::Parenthesis, quoted_span)));
let suffix = TokenStream::from_str(";proc_macro::TokenStream::from(proc_macro::TokenTree::Ident(ident))").unwrap();
let full_stream = TokenStream::from_iter([prefix, set_span_method, set_span_arg, suffix]);
full_stream
}
_ => unreachable!()
}
}
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