sirh3e/Rust

namespace Sirh3e.Rust.Result;

public readonly partial struct Result<TOk, TErr>
{
    /// <summary>
    /// Maps a Result&lt;TOk, TErr&gt; to Result&lt;T, TErr&gt; by applying a function to a contained Ok value, leaving an Err value untouched.
    /// This function can be used to compose the results of two functions.
    /// </summary>
    /// <param name="map"></param>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    /// <exception cref="ArgumentNullException">Throws only if map is null</exception>
    public Result<T, TErr> Map<T>(Func<TOk, T> map)
        => Match(ok =>
                     Result<T, TErr>.Ok((_ = map ?? throw new ArgumentNullException(nameof(map)))(ok)),
                 Result<T, TErr>.Err
                );
}