[Python-Dev] Classes and Metaclasses in Smalltalk

[Gordon McMillan]

Hmmm.

Some time ago, Tim asked the question: "Why do you wnat 
this stuff?". As far as I can recall, he got 2 answers: "So I 
don't have to 'initialize(Klass)'" and "me, too". I don't think 
those qualify as answers.

Some time ago (cf, types-sig brouhaha of a couple years ago) 
I concluded that the only purpose for this stuff was __getattr__ 
and __setattr__ hacks. I reached this conclusion by going 
nutzo using (Guido's) metaclass hook, and studying the 
available uses of ExtensionClass (I could find no public usage 
of Don's elegant madness).

I rather liked Guido's "Turtles all the way down" (but his 
description was so cryptic that my interpretation may have 
been a hallucination), and I suspect he's still headed that way.

Nonetheless, I would like to see this discussion of the 
elegance of SmallTalk's incompatible model (and how to fudge 
it in Python) balanced by some discussion of the expected 
pragmatic benefits. (That's a different topic from subclassing 
types.)

start-with-"if-God-wanted-metaclasses-he-wouldn't-have-
invented-proxies"-<wink>-ly y'rs






- Gordon