[Python-checkins] peps: Update 422 based on python-dev feedback

[Nick Coghlan]

On Fri, Jun 8, 2012 at 1:45 AM, Daniel Urban <urban.dani+py at gmail.com> wrote:
> On Thu, Jun 7, 2012 at 2:08 PM, nick.coghlan <python-checkins at python.org> wrote:
>> -* If the metaclass hint refers to an instance of ``type``, then it is
>> +* If the metaclass hint refers to a subclass of ``type``, then it is
>>   considered as a candidate metaclass along with the metaclasses of all of
>>   the parents of the class being defined. If a more appropriate metaclass is
>>   found amongst the candidates, then it will be used instead of the one
>
> I think here "instance" was correct (see
> http://hg.python.org/cpython/file/default/Lib/types.py#l76 and
> http://hg.python.org/cpython/file/cedc68440a67/Python/bltinmodule.c#l90).

Hmm, thinking back on it, the REPL experiments that persuaded me Terry
was right were flawed (I tried with object directly, but the signature
of __new__/__init__ would have been wrong regardless in that case).

Still, I'm kinda proving my point that I find it difficult to keep
*all* the details of metaclass invocation straight in my head, even
though I've been hacking on the type system for years. I've never had
anything even close to that kind of problem with class methods :)

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia