gistfile1.cs

public class Option<T> : IEnumerable<T>
{
  public T Value { get; private set; }
  public bool IsSome { get { return this != None; } }

  public static readonly Option<T> None = new Option<T>(default(T));
  public static Option<T> Some(T value)
  {
    return new Option<T>(value);
  }

  private Option(T value)
  {
    Value = value;
  }

  public IEnumerator<T> GetEnumerator()
  {
    if (IsSome)
      yield return Value;
  }

  IEnumerator IEnumerable.GetEnumerator()
  {
    return GetEnumerator();
  }

  public TRes Match<TRes>(Func<T, TRes> some, Func<TRes> none)
  {
    if (IsSome)
      return some.Invoke(Value);
    else
      return none.Invoke();
  }
  
  public void Match(Action<T> some, Action none)
  {
    if (IsSome)
      some.Invoke(Value);
    else
      none.Invoke();
  }
}