Lennart Regebro wrote: > On Mon, Jan 25, 2010 at 14:34, Nick Coghlan <ncogh...@gmail.com> wrote: >> However, returning NotImplemented generally implies that A and B are >> *different* classes > > Which is exactly the case here.
It wasn't in my tests though - I used the same class on both sides of the comparison. >> so I think this is more of a theoretical problem >> than a practical one. > > How so? The whole point of returning NotImplemented is to give the > other class a go. But if that other class implements this recipe, you > get infinite recursion. It seems to me that it means that this recipe > is broken, as it doesn't handle the other class returning > NotImplemented. Ah, you mean the case where both classes implement the recipe, but know nothing about each other and hence both return NotImplemented from their root comparison? OK, that sounds like a plausible real world problem with the recipe, but I'm not sure how difficult it would be to fix. For homogeneous collection of objects with nary a NotImplemented in site, it's still a decent recipe. Cheers, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia --------------------------------------------------------------- _______________________________________________ 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
