Currently, ``map(None, a)`` is recognized and converted to ``list(a)``
which is correct but quite useless.

``map(None, a, b, ...)`` is not treated specially.  An approximate
translation would be ``map(lambda *xs: xs, a, b, ...)`` which however
doesn't take into account that the new map cuts after the shortest
sequence instead of "filling up" the shorter ones with Nones.

That should probably produce a warning.

A full fix would be

list(map(fun, *zip(*itertools.zip_longest(a, b, ...))))

and if fun is None

list(map(lambda *xs: xs, *zip(*itertools.zip_longest(a, b, ...))))

Fixed in r75734.

I dare to disagree on this being an adequate fix. Request to reopen.

2009/10/27 Florian Mayer <report@bugs.python.org>:
>
> Florian Mayer <flormayer@aim.com> added the comment:
>
> I dare to disagree on this being an adequate fix. Request to reopen.

What would you prefer?

At least converting

map(None, a, b, ...)

to

map(lambda *xs: xs, a, b, ...)

I can understand if you prefer not to add the itertools.zip_longest
workaround, although that would be the correct translation, of course.

2009/10/27 Florian Mayer <report@bugs.python.org>:
>
> Florian Mayer <flormayer@aim.com> added the comment:
>
> At least converting
>
> map(None, a, b, ...)
>
> to
>
> map(lambda *xs: xs, a, b, ...)

Well, since that's not always correct, we should not translate to it.

When could this possibly be wrong, if I may ask?