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