On Apr 04, 2013, at 03:04 AM, Steven D'Aprano wrote: >On 04/04/13 01:16, Barry Warsaw wrote:
>> the other built-in types-as-functions, so int() calls __int__() which must >> return a concrete integer. >Why must it? I think that's the claim which must be justified, not just taken >as a given. When we call n = int(something), what's the use-case for caring >that n is an instance of built-in int but not of a subclass, and is that >use-case so compelling that it must be enforced for all uses of int() etc.? It's a consistency-of-implementation issue. Where built-in types are callable, they return concrete instances of themselves. This is true for e.g. list, tuple, dict, bytes, str, and should also be true of int. -Barry _______________________________________________ Python-Dev mailing list [email protected] http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com