Funtional Programming

FP.cs

struct Result<T> {
    public T Ok { get; }
    public Exception Error { get; }
    public bool IsFailed { get => Error != null; }
    public bool IsOk => !IsFailed;

    public Result (T ok) {
        Ok = ok;
        Error = default (Exception);
    }
    public Result (Exception error) {
        Error = error;
        Ok = default (T);
    }

    public R Match<R> (Func<T, R> okMap, Func<Exception, R> failureMap) => IsOk ? okMap (Ok) : failureMap (Error);
    public void Match (Action<T> okAction, Action<Exception> errorAction) {
        if (IsOk) okAction (Ok);
        else errorAction (Error);
    }
    public static implicit operator Result<T> (T ok) => new Result<T> (ok);
    public static implicit operator Result<T> (Exception error) => new Result<T> (error);
    public static implicit operator Result<T> (Result.Ok<T> ok) => new Result<T> (ok.Value);
    public static implicit operator Result<T> (Result.Failure error) => new Result<T> (error.Error);
}