Patrick Maupin wrote: > The only assertion that was made explicitly enough to be testable came > about in a followup to Aahz's original post, only AFTER someone asked > what the side-effects associated with __slots__ were. Aahz responded: > > > The main one is that inheritance becomes difficult to nearly-impossible. > > But this statement is either wrong or incomplete. [snip]
It's definitely an overstatement. I myself have written a library (Dice3DS, q.v., which is a pure-Python 3DS library), which used both __slots__ and inheritance extensively, with no problems. I wouldn't even say it was difficult, let alone nearly impossible, but it definitely required care. Dice3DS was my learning experience with metaclasses (if you want to talk about difficult :). I wrote it soon after new-style classes made their debut, and didn't realize what the intended purpose of __slots__ was. I definitely wouldn't use __slots__ if I were it writing it today; instead, I'd use a homemade attribute checker that was free from __slots__'s weird nuances. In fairness to myself, some 3DS files have thousands or tens of thousands of chunks, so using __slots__ probably did save quite a bit of byteage, but that consideration had nothing to do with my decision to use __slots__. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
