example operator: add

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;
}