Macro features

macro_rules! features {
    (
        $(
            $(#[$attr:meta])*
            ($stab:ident, $feature:ident, $version:expr, $docs:expr),
        )*
    ) => { ... };
}

A listing of stable and unstable new syntax in Cargo.toml.

This generates definitions and impls for Features and Feature for each new syntax.

Note that all feature names in the macro invocation are valid Rust identifiers, but the _ character is translated to - when specified in the cargo-features manifest entry in Cargo.toml.

See the module-level documentation for the process of adding a new syntax.