Error Index Gen

diagnostics.rs

register_long_diagnostics! {
    E001: r##"hello"##,
    E002: r##"world"##,
}

register_diagnostics! {
    E003,
    E004
}

main.rs

#![feature(trace_macros)]
trace_macros!(true);

fn main() {
    macro_rules! register_diagnostic {
        ($code:tt, $description:tt) => { println!( "code is {}", stringify!($code)); };
        ($code:tt) => { println!( "code is {}", stringify!($code)); }
    }

    macro_rules! register_diagnostics {
        ($($code:tt),*) => {
            $(register_diagnostic! { $code })*
        };
        ($($code:tt),*,) => {
            $(register_diagnostic! { $code })*
        };
    }

    macro_rules! register_long_diagnostics {
        ($($code:tt: $description:tt),*) => {
            $(register_diagnostic! { $code, $description })*
        };
        ($($code:tt: $description:tt),*,) => {
            $(register_diagnostic! { $code, $description })*
        };
    }

    #[path = "diagnostics.rs"] mod diags;

}