void IOperation.Exec(DataStack stack, IDataAccess extdata)
{
object ob = stack.Pop();
object oa = stack.Pop();
bool isTrue = OperationHelpers.EvaluateAsLogicalTrue(oa);
stack.Push(isTrue ? ob : oa);
}
void IOperation.Exec(DataStack stack, IDataAccess extdata)
{
object oa = stack.Pop();
bool isTrue = OperationHelpers.EvaluateAsLogicalTrue(oa);
if (isTrue)
{
stack.InstructionIndex = this.Position - 1;
}
}