[Python-ideas] Let's be more orderly!

[Gregory P. Smith]

On Tue, May 14, 2013 at 5:36 PM, Tim Delaney <timothy.c.delaney at gmail.com>wrote:

> On 15 May 2013 09:34, Steven D'Aprano <steve at pearwood.info> wrote:
>
>>
>> I don't think that is a particularly good analogy. Stable sorting is
>> intuitively correct. Treating keyword args differently according to
>> their order is intuitively the wrong thing to do, at least most of the
>> time.
>>
>
> The argument *for* an ordered kwargs however is that same one that was
> used for Enums iterating in definition order by default - it's an ordering
> that can't be recovered once it's lost.
>
> However, it's not a property that I think is absolutely necessary for
> kwargs and we shouldn't lose performance to gain that property, but there
> have been times when I would have liked it.
>

> Barry created a new dict implementation a while back that as a side-effect
> retained insertion order so long as no keys were removed. That would be
> suitable IMO for kwargs as a guarantee - definition order so long as
> nothing has been removed. It was discussed and there was the suggestion to
> actively break this functionality in order to prevent people relying on it.
> I'm not sure what the end result of the discussion was off the top of my
> head.
>

There was also some conversation at the pycon sprints this year about if
keyword arguments could use an ordered dict or not but I wasn't paying
enough attention to that to be able to give a summary of what was discussed.

My gut feeling is that it'd add overhead even though I would find it useful
at times.

-gps
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-ideas/attachments/20130514/17868669/attachment-0001.html>