[Python-Dev] [Python-checkins] peps: PEP 422 rewrite to present an idea that a) isn't crazy and b) it turns out

[PJ Eby]

On Wed, Jun 6, 2012 at 6:07 PM, Eric Snow <ericsnowcurrently at gmail.com>wrote:

> On Wed, Jun 6, 2012 at 5:40 AM, nick.coghlan <python-checkins at python.org>
> wrote:
> > +
> > +Alternatives
> > +============
> > +
>
> Would it be worth also (briefly) rehashing why the class instance
> couldn't be created before the class body is executed*?  It might seem
> like a viable alternative if you haven't looked at how classes get
> created.
>

Backwards compatibility is really the only reason.  So it'll have to wait
till Python 4000.  ;-)

(Still, that approach is in some ways actually better than the current
approach: you don't need a __prepare__, for example.  Actually, if one were
designing a class creation protocol from scratch today, it would probably
be simplest to borrow the __enter__/__exit__ protocol, with __enter__()
returning the namespace to be used for the suite body, and __exit__()
returning a finished class...  or something similar.  Python-ideas stuff,
to be sure, but it could likely be made a whole lot simpler than the
current multitude of hooks, counter-hooks, and extended hooks.)
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