"Michael Hudson" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Michael Chermside <[EMAIL PROTECTED]> writes: > >> I'm changing the subject line because I want to convince everyone that >> the problem being discussed in the "unicode hell" thread has nothing >> to do with unicode and strings. It's all about dicts. > > I'd say it's more to do with __eq__. It's a strange __eq__ method > that raises an Exception, IMHO.
I agree; a == b should always work, certainly unless explicitly programmed otherwise in Python for a particular class. So I think the proper solution is fix the buggy __eq__ method to return False instead. If a byte string does not have a default (ascii) text interpretation, then it obviously is not equal to any particular unicode text. The fundamental axiom of sets and hence of dict keys is that any object/value either is or is not a member (at any given time for 'mutable' set collections). This requires that testing an object for possible membership by equality give a clean True or False answer. > Please do realize that the motivation for this change was hours and > hours of tortous debugging caused by a buggy __eq__ method making keys > "impossibly" seem to not be in dictionaries. So why not fix the buggy __eq__ method? >> 2.4, fails in 2.5, and arguably ought to work fine. I think we should >> restore the behavior of dicts that when they compare keys for >> equality they suppress exceptions (treating the objects as unequal), >> or at LEAST retain the behavior for one more release making it a >> warning this time. > > Please no. Here's just one piece of evidence that the 2.4 semantics > are pretty silly too: We mostly agreed half a decode ago that 1/2 should be .5 instead of 0, but to avoid breaking code, have (or Guido has) refrained from yet making the change the default. To me, the same principle applies here at least as strongly. Terry Jan Reedy _______________________________________________ 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
