Raymond Hettinger wrote:
class Pane(object): __slots__ = ('background', 'foreground', 'size', 'content') background = 'black' foreground = 'white' size = (80, 25) ...which doesn't work since the class variable overwrites the __slots__ descriptor.
Aahz replies:
Why not do the initializing in __init__?
I presume that Raymond's concern was not that there wouldn't be a way to do initialization, but that this would become a new c.l.p FAQ and point of confusion for newbies. Unfortunately, I fear that it will. Already I am seeing that people are "discovering" class variables as a sort of "initialized instance variable" instead of using __init__ as they "ought" to. Of course, it's NOT an initialized instance variable, but newbies stumble across it and seem to prefer it to using __init__. Combine this with the fact that newbies from staticly typed languages tend to think of __slots__ as "practically mandatory" (because it prevents the use of instance variables not pre-declared, which they erroniously think is a good thing) rather than the special purpose performance hack that it REALLY is, and you have a recipe for trouble. I'm not quite sure how to present things so as to steer them right, but there's definitely a potential pitfall here. -- Michael Chermside