public static Icod.Collections.Immutable.IStack<Type> Add( Icod.Collections.Immutable.IStack<Type> stack ) {
	var a = stack.Peek();
	stack = stack.Pop();
	var b = stack.Peek();
	stack = stack.Pop();
	var q = ( ( a.Value is System.Decimal ) || ( b.Value is System.Decimal ) )
		? Type.CreateDecimal( System.Convert.ToDecimal( b.Value ) + System.Convert.ToDecimal( a.Value ) )
		: ( ( a.Value is System.Single ) || ( b.Value is System.Single ) )
			? Type.CreateSingle( System.Convert.ToSingle( b.Value ) + System.Convert.ToSingle( a.Value ) )
			: Type.CreateInt( System.Convert.ToInt32( b.Value ) + System.Convert.ToInt32( a.Value ) )
	;
	stack = stack.Push( q );
	return stack;
}