In the DB::sub routine I want to print the arguments of a method. This works fine for most data, but is crashing (recursion called over and over again) when the "" operator is overloaded to call a sub, since this calls DB::sub again and from here on forever. Is there a way to prevent this? I need only a way to check this and continue if DB::sub is not called by an overloaded "". And then there is the question what to print instead of the "" that would call the sub.