src/test/ui/proc-macro/auxiliary/custom-quote.rs

   1 // force-host
   2 // no-prefer-dynamic
   3 // ignore-tidy-linelength
   4
   5 #![feature(proc_macro_quote)]
   6 #![crate_type = "proc-macro"]
   7
   8 extern crate proc_macro;
   9 use std::iter::FromIterator;
  10 use std::str::FromStr;
  11 use proc_macro::*;
  12
  13 #[proc_macro]
  14 pub fn custom_quote(input: TokenStream) -> TokenStream {
  15     let mut tokens: Vec<_> = input.into_iter().collect();
  16     assert_eq!(tokens.len(), 1, "Unexpected input: {:?}", tokens);
  17     match tokens.pop() {
  18         Some(TokenTree::Ident(ident)) => {
  19             assert_eq!(ident.to_string(), "my_ident");
  20
  21             let proc_macro_crate = TokenStream::from_str("::proc_macro").unwrap();
  22             let quoted_span = proc_macro::quote_span(proc_macro_crate, ident.span());
  23             let prefix = TokenStream::from_str(r#"let mut ident = proc_macro::Ident::new("my_ident", proc_macro::Span::call_site());"#).unwrap();
  24             let set_span_method = TokenStream::from_str("ident.set_span").unwrap();
  25             let set_span_arg = TokenStream::from(TokenTree::Group(Group::new(Delimiter::Parenthesis, quoted_span)));
  26             let suffix = TokenStream::from_str(";proc_macro::TokenStream::from(proc_macro::TokenTree::Ident(ident))").unwrap();
  27             let full_stream = TokenStream::from_iter([prefix, set_span_method, set_span_arg, suffix]);
  28             full_stream
  29         }
  30         _ => unreachable!()
  31     }
  32 }