[Python-Dev] Ordering keyword dicts

[Maciej Fijalkowski]

On Sun, May 19, 2013 at 4:40 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> On Sun, May 19, 2013 at 11:01 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:
>> The main use case seems to be the OrderedDict constructor itself.
>> Otherwise, I can't think of any situation where I would've wanted it.
>
> I've had a couple related to populating other mappings where order
> matters, at least from a predictability and readability perspective,
> even if it's not strictly required from a standards compliance point
> of view (think writing XML attributes, etc).
>
> I quite liked the idea of a simple flag attribute on function objects
> that the interpreter checked, with a decorator in functools (or even
> the builtins) to set it. It's not a particularly elegant solution, but
> it would get the job done with minimal performance impact on existing
> functions.
>
> Cheers,
> Nick.

Note that raymonds proposal would make dicts and ordereddicts almost
exactly the same speed.