At 10:17 PM 12/3/2007 -0700, Neil Toronto wrote: >Phillip J. Eby wrote: > > Actually, you're missing the part where such evil code *can't* muck > > things up for class dictionaries. Type dicts aren't reachable via > > ordinary Python code; you *have* to modify them via setattr. (The > > __dict__ of types returns a read-only proxy object, so the most evil > > rich compare you can imagine still can't touch it.) > >Interesting. But I'm going to have to say it probably wouldn't work as >well, since C code can and does alter tp_dict directly. Those places in >the core would have to be altered to invalidate the cache.
Eh? Where is the type dictionary altered outside of setattr and class creation? > There's also >the issue of extensions, which so far have been able to alter any >tp_dict without problems. Do you have any actual examples? Believe me, I'm the last person to suggest removing useful hack, er, hooks. :) But I don't think that type __dict__ munging is actually common at all. >It'd also be really annoying for a class to >have to notify all of its subclasses when one of its attributes changed. It's not all subclasses - only those subclasses that don't shadow the attribute. Also, it's not necessarily the case that notification would be O(subclasses) - it could be done via a version counter, as in your approach. Admittedly, that would require an extra bit of indirection, since you'd need to keep (and check) counters for each descriptor. _______________________________________________ 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
