commit	11dc4cdb9bd0745595d526453ef65dadaf4871d6	[log] [tgz]
author	David Tolnay <dtolnay@gmail.com>	Fri Nov 25 12:49:46 2016 -0500
committer	GitHub <noreply@github.com>	Fri Nov 25 12:49:46 2016 -0500
tree	5b5e55bdd7d166b8bbfefabedc8ce3bb8166150a
parent	9a9412a5b66c3b80d9232fd0ced1f6c1f778747e [diff]
parent	b8e28326c86babdc70d87ba52c0048feb483440f [diff]

tree: 5b5e55bdd7d166b8bbfefabedc8ce3bb8166150a

README.md

Rust Quasi-Quoting

Quasi-quoting without a Syntex dependency, intended for use with Macros 1.1.

[dependencies]
quote = "0.3.9"

#[macro_use]
extern crate quote;

Interpolation is done with #var:

let tokens = quote! {
    struct SerializeWith #generics #where_clause {
        value: &'a #field_ty,
        phantom: ::std::marker::PhantomData<#item_ty>,
    }

    impl #generics serde::Serialize for SerializeWith #generics #where_clause {
        fn serialize<S>(&self, s: &mut S) -> Result<(), S::Error>
            where S: serde::Serializer
        {
            #path(self.value, s)
        }
    }

    SerializeWith {
        value: #value,
        phantom: ::std::marker::PhantomData::<#item_ty>,
    }
};

Repetition is done using #(...)* or #(...),* very similar to macro_rules!:

#(#var)* - no separators
#(#var),* - the character before the asterisk is used as a separator
#( struct #var; )* - the repetition can contain other things
#( #k => println!("{}", #v), )* - even multiple interpolations

The return type of quote! is quote::Tokens. Tokens can be interpolated into other quotes:

let t = quote! { /* ... */ };
return quote! { /* ... */ #t /* ... */ };

Call to_string() or as_str() on a Tokens to get a String or &str of Rust code.

The quote! macro relies on deep recursion so some large invocations may fail with "recursion limit reached" when you compile. If it fails, bump up the recursion limit by adding #![recursion_limit = "128"] to your crate. An even higher limit may be necessary for especially large invocations.

License

Licensed under either of

Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.