[Python-Dev] future_builtins (was: Backporting PEP 3127 to trunk)

[Guido van Rossum]

On Sun, Feb 24, 2008 at 7:02 PM, Neal Norwitz <nnorwitz at gmail.com> wrote:
> On Sun, Feb 24, 2008 at 6:57 PM, Guido van Rossum <guido at python.org> wrote:
>  > On Sat, Feb 23, 2008 at 5:59 PM, Neal Norwitz <nnorwitz at gmail.com> wrote:
>  >  > On Sat, Feb 23, 2008 at 8:06 AM, Guido van Rossum <guido at python.org> wrote:
>  >  >  >
>  >  >  >  I do think map() and filter() should issue a warning under -3 when the
>  >  >  >  first arg is None. (Or does 2to3 detect this now?)
>  >  >
>  >  >  What's wrong with filter(None, seq)?  That currently works in 3k:
>  >  >
>  >  >  >>> filter(None, range(5))
>  >  >  <itertools.ifilter object at 0x2b5be60da450>
>  >  >  >>> [x for x in _]
>  >  >  [1, 2, 3, 4]
>  >
>  >  But that's a bug -- it's been spec'ed that this will stop working.
>  >  (Can't remember where, perhaps PEP 3100?)
>
>  I looked in 3100 and didn't see it.

Hm. Well, it's still the plan.

>  >  >  (Side note, shouldn't we change the names for filter/map?)
>  >
>  >  Huh? What? Why?
>
>  The function name returned by repr: itertools.ifilter.

I see. Yes, that's a bug. You could say that the way map and filter
are implemented in py3k at the moment is a prototype.

I'll file bugs for both of these.

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)