On Thu, Apr 4, 2013 at 1:50 PM, Tim Delaney <tim.dela...@aptare.com> wrote: > I fall into: > > 1. int(), float(), str() etc should return that exact class (and > operator.index() should return exactly an int). > > 2. It could sometimes be useful for __int__() and __index__() to return a > subclass of int. > > So, for the int constructor, I would have the following logic (assume > appropriate try/catch): > > def __new__(cls, obj): > i = obj.__int__() > > if type(i) is int: > return i > > return i._internal_value
CPython can solve this in C using an unsafe cast, and the code that checks for allowable subclasses of int actually ensures such a cast will work. But it still feels wrong; __int__ should be expected to do the work. -- --Guido van Rossum (python.org/~guido) _______________________________________________ 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
