metaclasses: timestamping instances

[km]

Hi,

But why does it show  varied difference in the time  between a and b
instance creations when __metaclass__ hook is used and when not used in
class Y ? I dont understand that point !

KM
On 9/1/07, Michele Simionato <michele.simionato at gmail.com> wrote:
>
> On Sep 1, 6:07 pm, Steve Holden <st... at holdenweb.com> wrote:
> <snip>
> >
> > Debugging with Wing IDE and examining the classes at a breakpoint shows
> > this to be true (even after Y's __metaclass__ assignment is commented
> out):
> >
> >  >>> X.__metaclass__
> > <class '__main__.Meta'>
> >  >>> Y.__metaclass__
> > <class '__main__.Meta'>
> >  >>>
>
> For the benefit of the readers I will just point out that in order
> to determine the metaclass of a class it is far better NOT to relay on
> the
> __metaclass__ attribute. The right thing to to is to look at the
> __class__
> attribute, or to use type. Here is a (made up) example
> where .__metaclass__ gives
> the wrong result:
>
>
> In [9]: class M(type): pass
>    ...:
>
> In [10]: class B: __metaclass__ = M
>    ....:
>
> In [11]: B.__metaclass__ = None # now the hook is set to None, but the
> metaclass does not change
>
> In [12]: B.__class__
> Out[12]: <class '__main__.M'>
>
>        Michele Simionato
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-list/attachments/20070903/f65cbd14/attachment.html>