[Python-Dev] small Grammar questions

[Brett Cannon]

On Feb 19, 2008 6:15 PM, Steve Holden <steve at holdenweb.com> wrote:
> Steve Holden wrote:
> [...]
> > The one that surprised me was the legality of
> >
> >      def eggs((a, )=c):
> >          pass
> >
> > That just seems like unpacking-abuse to me.
> >
> Needless to say, a call that tries to *use* the default value fails
> horribly, as the parameter form does require an iterable:
>
>  >>> def eggs((a, )=2.1):
> ...   pass
> ...
>  >>> eggs()
> Traceback (most recent call last):
>    File "<stdin>", line 1, in <module>
>    File "<stdin>", line 1, in eggs
> TypeError: 'float' object is not iterable
>  >>> eggs((2.1, ))
>
>  >>>

And this is another reason why they will not appear in Python 3.0.

-Brett