On Feb 8, 5:38 pm, Freek Dijkstra <[EMAIL PROTECTED]> wrote: If you want to subclass, my initial example did not cover that. This will, or at least, I don't have any problems with similar code:
... def __new__(cls,uri,*args,**kwds): ... try: ... return cls.cache[(cls,uri)] #notice that I added the class itself as a key. ... except KeyError: ... print "cache miss" ... res = cls.cache[(cls,uri)] = object.__new__(cls) ... return res Your mileage apparently varies, but I'm still not sold on using a metaclass. Just because it is a bit fancy for the requirements, IMHO. Later you may have cached/singleton classes that really need a metaclass for something else, with subclasses of _those_ that don't want caching. That's definitely just my $.02 there, I don't necessarily expect others to share my prejudices and misgivings. Anyway, I should post answers more often - I learned more today than by asking questions ;-) Txs all, for the has_key/in performance pointers, they are exactly contrary to what I would have thought. Cheers -- http://mail.python.org/mailman/listinfo/python-list
