On Tue, Feb 12, 2013 at 8:35 AM, Guido van Rossum <gu...@python.org> wrote: > On Mon, Feb 11, 2013 at 2:29 PM, Nick Coghlan <ncogh...@gmail.com> wrote: >> 4.__class__ is already bound as soon as we have a class object to bind it >> to, so we can't move it any earlier. However, it's already early enough to >> let references to it from the new method (including the implied one in >> zero-arg super) work properly. The black magic that is zero-arg super also >> deals with PJE's concern about propagating the actual class up the MRO (as >> it is equivalent to "super(__class__, first_argument)"). > > So where is it not bound when a metaclass runs? I guess in the metaclass's > __new__()? Because in the metaclass's __init__() it should exist IIUC.
I stand corrected, we don't *quite* bind it as soon as the class object exists - we bind it as soon as the call to the metaclass returns. So even though the class object exists when __init__ runs, it isn't bound to __class__ yet. Given that the class construction machinery treats the metaclass constructor as an opaque callable, trying to get the cell binding to happen between the call to __new__ and the one to __init__ would be rather challenging (Translation: I'm not sure where you would even start...). Regards, 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
