Contributing to Helix

You can do print debugging by using the log::error! macro, and then see the results with :log-open.

You can also use the following macro to mimic std's dbg. The implementation is the same, but it uses log::error! instead of eprintln!.

macro_rules! dbg {
    // NOTE: We cannot use `concat!` to make a static string as a format argument
    // of `eprintln!` because `file!` could contain a `{` or
    // `$val` expression could be a block (`{ .. }`), in which case the `eprintln!`
    // will be malformed.
    () => {
        log::error!("[{}:{}:{}]", file!(), line!(), column!())
    };
    ($val:expr $(,)?) => {
        // Use of `match` here is intentional because it affects the lifetimes
        // of temporaries - https://stackoverflow.com/a/48732525/1063961
        match $val {
            tmp => {
                log::error!("[{}:{}:{}] {} = {:#?}",
                    file!(), line!(), column!(), stringify!($val), &tmp);
                tmp
            }
        }
    };
    ($($val:expr),+ $(,)?) => {
        ($(dbg!($val)),+,)
    };
}