PJE wrote: > Isn't the simplest way to cache attribute > lookups to just have a cache dictionary in the type, > and update that dictionary whenever a change is > made to a superclass? That's essentially how > __slotted__ attribute changes on base classes > work now, isn't it?
Neil Toronto wrote: > The nice thing about caching pointers to dict > entries is that they don't change as often as > values do. Is this really true for namespaces? I was thinking that the typical namespace usage is a bunch of inserts (possibly with lookups mixed in), followed by never changing it again until it is deallocated. > There are fewer ways to invalidate an > entry pointer: inserting set, resize, clear, and delete. I'm not sure how to resize without an inserting set. I'm not sure I've ever seen clear on a namespace. (I have seen it on regular dicts being used as a namespace, such as tcl config options.) I have seen deletes (deleting a temp name) and non-inserting sets ... but they're both rare enough that letting them force the slow path might be a good trade, if the optimization is otherwise simpler. > Rare updating also means it's okay to invalidate the > entire cache rather than single entries Changing __bases__ seems to do that already. (See http://svn.python.org/view/python/trunk/Objects/typeobject.c?rev=59106&view=markup functions like update_subclasses.) So I think an alternate version PJE's question would be: Why not just extend that existing mechanism to work on non-slot, non-method attributes? -jJ _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
