/// <summary>
/// Helper for registering a minus operator.
/// </summary>
/// <param name="left">The type on the left side.</param>
/// <param name="right">The type on the right side.</param>
/// <param name="sub">The function to execute.</param>
protected static void RegisterMinus(Type left, Type right, Func <Value, Value, Value> sub)
{
MinusOperator.Register(left, right, sub);
}
