[Python-Dev] [RELEASED] Python 2.7 alpha 2

Steven Bethard steven.bethard at gmail.com
Tue Jan 12 06:57:18 CET 2010

On Mon, Jan 11, 2010 at 4:11 PM, Barry Warsaw <barry at python.org> wrote:
> As an example, the one library I've already ported used a metaclass.  I don't
> see any way to specify that the metaclass should be used in a portable way.
> In Python 2.6 it's:
> class Foo:
>    __metaclass__ = Meta
> and in Python 3 it's:
> class Foo(metaclass=Meta):
> 2to3 made that pain go away.

Actually there's a solution to this one too:

    FooBase = Meta('FooBase', (), {})
    class Foo(FooBase):

That should work in Python 2.X and 3.X.

I've got argparse running on Python 2.3-3.1, and the changes were
pretty easy. You can see them all in the revision here:


I have aspirations of putting all of the tricks I learned up up on the
Wiki somewhere, but I just haven't had the time.

Where did you get that preposterous hypothesis?
Did Steve tell you that?
        --- The Hiphopopotamus

More information about the Python-Dev mailing list