typed-quote

A fully typed quote!() alternative for both proc-macro and proc-macro2.

Quick start

Output TokenStream

typed_quote::quote!(...) returns a fully typed value that implements [IntoTokens], [ToTokens], [WithSpan], [IntoTokenTree] or [ToTokenTree] depending on the quoted content.

• Call ts.into_token_stream() to get [proc_macro::TokenStream].
• Call ts.into_token_stream2() to get [proc_macro2::TokenStream].

use typed_quote::prelude::*;

let crate_name = quote!("typed-quote");
let tokens = quote!(hello #crate_name !);

let ts: proc_macro2::TokenStream = tokens.into_token_stream2();

assert_eq!(ts.to_string(), r#"hello "typed-quote" !"#);

Set span

• Call ts.with_default_span(span) to specify a span only for un-spanned tokens in ts.

  • quote!(un-spanned).with_default_span(span) will specify span for all tokens.
  • quote!(#quoted_var).with_default_span(span) will call quoted_var.with_default_span(span).
  • proc_macro::TokenStream::from_str("...").unwrap().with_default_span(span) will not change span because proc_macro::TokenStream already has a span.

• Call ts.with_replaced_span(span) to set span for all tokens in ts.

  • Note that, if the ident of [proc_macro::Ident] and [proc_macro2::Ident] is exactly $crate, then its span will not be replaced.

Comparison with ::quote

typed_quote::typed_quote!() is an alias of typed_quote::quote!() so you can disambiguate typed_quote!() from quote::quote!().

• typed_quote is new, not well tested, and will contain breaking changes in the future. You should use ::quote for production.

• ::quote::quote!() returns a proc_macro2::TokenStream.

  typed_quote!() returns a fully typed struct that implements IntoTokens and you can decide to output proc_macro::TokenStream or proc_macro2::TokenStream.

• ::quote has quote_spanned!(span => ...).

  But in typed_quote, use typed_quote!(...).with_default_span(span) instead.

• ::quote::quote!(#var) only references &var but typed_quote!(#var) moves var. Since &impl ToTokens implements both IntoToken and Copy, let var = &var; typed_quote!(#var) will work if var is a value of impl ToTokens.

• ::quote::ToTokens is dyn-

cargo features

• alloc (default)

  This feature implements traits for Box, Rc.

  This library is no_std and only alloc is enabled by default.

• proc-macro and proc-macro2

  Enable one or both of these features if necessary:

  cargo add typed-quote --features proc-macro
  cargo add typed-quote --features proc-macro2
  cargo add typed-quote --features proc-macro,proc-macro2
  

  You don't need to enable them when you're writing a library that just inputs/outputs tokens. Users of your library can decide which feature to enable and call the corresponding into_token_stream or into_token_stream2.

  cargo add typed-quote
  

  use typed_quote::prelude::*;
  
  fn braced(stream: impl IntoTokens) -> impl IntoTokenTree {
      quote!({ stream })
  }