[Python-Dev] PEP 492 quibble and request

[Guido van Rossum]

On Wed, Apr 29, 2015 at 5:59 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:

> On 30 April 2015 at 10:21, Ethan Furman <ethan at stoneleaf.us> wrote:
> > From the PEP:
> >
> >> Why not a __future__ import
> >>
> >> __future__ imports are inconvenient and easy to forget to add.
> >
> > That is a horrible rationale for not using an import.  By that logic we
> > should have everything in built-ins.  ;)
>

This response is silly. The point is not against import but against
__future__. A __future__ import definitely is inconvenient -- few people I
know could even recite the correct constraints on their placement.


> It is also makes things more painful than they need to be for syntax
> highlighters.


Does it? Do highlighters even understand __future__ imports? I wouldn't
mind if a highlighter always highlighted 'async' and 'await' as keywords
even where they aren't yet -- since they will be in 3.7.


> 'as' went through the "not really a keyword" path, and
> it's a recipe for complexity in the code generation toolchain and
> general quirkiness as things behave in unexpected ways.
>

I don't recall that -- but it was a really long time ago so I may
misremember (did we even have __future__ at the time?).


> We have a defined process for introducing new keywords (i.e.
> __future__ imports) and the PEP doesn't adequately make the case for
> why we shouldn't use it here.
>

That's fair. But because of the difficulty in introducing new keywords,
many proposals have been shot down or discouraged (or changed to use
punctuation characters or abuse existing keywords) -- we should give Yury
some credit for figuring out a way around this. Honestly I'm personally on
the fence.

-- 
--Guido van Rossum (python.org/~guido)
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