litrs: parsing and inspecting Rust literals

litrs offers functionality to parse Rust literals, i.e. tokens in the Rust programming language that represent fixed values. This is particularly useful for proc macros, but can also be used outside of a proc-macro context.

Why this library? Unfortunately, the proc_macro API shipped with the compiler offers no easy way to inspect literals. There are mainly two libraries for this purpose: syn and literalext. The latter is deprecated. And syn is oftentimes overkill for the task at hand, especially when developing function like proc-macros (e.g. foo!(..)). This crate is a lightweight alternative (it compiles very quickly). Also, when it comes to literals, litrs offers a bit more flexibility and a few more features compared to syn.

While this library is fairly young, it is extensively tested and I think the number of parsing bugs should already be very low. I'm interested in community feedback! If you consider using this, please speak your mind in this issue.

use litrs::Literal;

let lit = Literal::parse("3.14f32").expect("failed to parse literal");
match lit {
    Literal::Float(lit) => {
        println!("{:?}", lit.type_suffix());
    }
    Literal::Bool(lit) => { /* ... */ }
    Literal::Integer(lit) => { /* ... */ }
    Literal::Char(lit) => { /* ... */ }
    Literal::String(lit) => { /* ... */ }
    Literal::Byte(lit) => { /* ... */ }
    Literal::ByteString(lit) => { /* ... */ }
}

See the documentation for more information.

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option. Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.