On 5/1/07, Raymond Hettinger <[EMAIL PROTECTED]> wrote: > The alternative is to code the automatic finalization steps using > weakref callbacks. For those used to using __del__, it takes a little > while to learn the idiom but essentially the technique is hold a proxy > or ref with a callback to a boundmethod for finalization: > self.resource = resource = CreateResource() > self.callbacks.append(proxy(resource, resource.closedown)) > In this manner, all of the object's resources can be freed automatically > when the object is collected. Note, that the callbacks only bind > the resource object and not client object, so the client object > can already have been collected and the teardown code can be run > without risk of resurrecting the client (with a possibly invalid state).
That alternative is pretty ugly, and I think we found some cases where it required major rewriting. (I don't have them handy, but may end up searching for them again, if need be.) A smaller change would be to add __close__ (which covers most use cases), or even to give __del__ the __close__ semantics. The key distinction is that __close__ says to go ahead and break the cycle in an arbitrary location, rather than immortalizing it. -jJ _______________________________________________ Python-3000 mailing list Python-3000@python.org http://mail.python.org/mailman/listinfo/python-3000 Unsubscribe: http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
