Mayhaps.cs

public abstract class Mayhaps<T>
{
	private Mayhaps() { }

	public abstract bool HasValue { get; }

	public abstract T Value { get; }

	private class MayhapsIndeed : Mayhaps<T>
	{
		private readonly T _value;

		public MayhapsIndeed(T value)
		{
			_value = value;
		}

		public override bool HasValue => true;

		public override T Value => _value;
	}

	private class MayhapsSorry : Mayhaps<T>
	{
		public override bool HasValue => false;

		public override T Value
		{
			get { throw new InvalidOperationException("Nothing here."); }
		}
	}

	private static MayhapsSorry _sorry = new MayhapsSorry();

	public static Mayhaps<T> Indeed(T value) =>
		new MayhapsIndeed(value);

	public static Mayhaps<T> Sorry => _sorry;
}