On Sat, 30 Dec 2006 11:08:10 -0800, johnf wrote: > Very detailed. But I was attempting to debug some code which subclassed > other code. I got a traceback that something like "no > mySubClass.__source.query() did not exist". The superclass had something > like "myClass.__source.query(sql)" which worked > but "mySubClass.__source.query(sql)" did not work.
That's right, exactly as expected. As I said before, Python mangles the name of double-leading underscore class attributes. So when the developer of myClass wrote myClass.__source.query(sql) at compile time Python changes that to myClass._myClass__source.query(sql) When you write mySubClass.__source.query() it doesn't work because there is no attribute "__source". You need to change that to "_myClass__source" -- even when it appears in mySubClass. > So I tried to debug > using "dir(myClass.__source)" and got an error. And I also got error when > I "dir(mySubClass.__source". So how could I have debugged the problem if > dir() will not display information on the __source? I hope that explains > my issue. This isn't actually a problem with dir -- although dir does sometimes hide methods, this isn't one of those cases. This is a case of you not knowing that Python mangles the name of __attributes. What you should have done is call dir(myClass), in which case you almost certainly would have seen _myClass__source listed. -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
