On Wed, 2005-10-05 at 12:56 -0400, Jonathan LaCour wrote:
> > class Spam(object):
> > cache = {}
> > def __new__(cls, x):
> > if cls.cache.has_key(x):
> > return cls.cache[x]
> > def __init__(self, x):
> > self.x = x
> > self.cache[x] = self
> >
> > a = Spam('foo')
> > b = Spam('foo')
> >
> > Well, in this case a and b are identical... to None! I assume this is
> > because the test in __new__ fails so it returns None, I need to then
> > create a new Spam.. but how do I do that without calling __new__
> > again?
> > I can't call __init__ because there's no self...
> >
> >
>
> Oops, you forgot to return object.__new__(cls, x) in the case the
> object isn't in the cache. That should fix it.
Okay, one more question... say I then
c = Spam('bar')
del a
del b
I've removed all references to the object, except for the cache. Do I
have to implement my own garbage collecting is or there some "magical"
way of doing this within Python? I pretty much want to get rid of the
cache as soon as there are no other references (other than the cache).
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