32 lines
1.3 KiB
Rust
32 lines
1.3 KiB
Rust
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// force-host
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// no-prefer-dynamic
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// ignore-tidy-linelength
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#![feature(proc_macro_quote)]
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#![crate_type = "proc-macro"]
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extern crate proc_macro;
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use std::str::FromStr;
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use proc_macro::*;
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#[proc_macro]
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pub fn custom_quote(input: TokenStream) -> TokenStream {
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let mut tokens: Vec<_> = input.into_iter().collect();
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assert_eq!(tokens.len(), 1, "Unexpected input: {:?}", tokens);
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match tokens.pop() {
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Some(TokenTree::Ident(ident)) => {
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assert_eq!(ident.to_string(), "my_ident");
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let proc_macro_crate = TokenStream::from_str("::proc_macro").unwrap();
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let quoted_span = proc_macro::quote_span(proc_macro_crate, ident.span());
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let prefix = TokenStream::from_str(r#"let mut ident = proc_macro::Ident::new("my_ident", proc_macro::Span::call_site());"#).unwrap();
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let set_span_method = TokenStream::from_str("ident.set_span").unwrap();
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let set_span_arg = TokenStream::from(TokenTree::Group(Group::new(Delimiter::Parenthesis, quoted_span)));
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let suffix = TokenStream::from_str(";proc_macro::TokenStream::from(proc_macro::TokenTree::Ident(ident))").unwrap();
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let full_stream: TokenStream = std::array::IntoIter::new([prefix, set_span_method, set_span_arg, suffix]).collect();
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full_stream
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}
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_ => unreachable!()
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}
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}
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