[Python-ideas] Proto-PEP: Preserving the order of **kwargs in a function.

[Nick Coghlan]

On 6 April 2014 15:43, Eric Snow <ericsnowcurrently at gmail.com> wrote:
> Here's the proper proposal I promised.  Hopefully it reflects our
> discussions and the past ones too.  My goal here is to focus in on
> what I consider to be the most viable approach, which capturing the
> gist of the various concerns and alternatives.  There are still a few
> small gaps that I will work on as time permits.  Feedback is welcome.

Nice! One specific comment below.

> Relationship to **-unpacking syntax
> -----------------------------------
>
> The ** unpacking syntax in function calls has no special connection with
> this proposal.  Keyword arguments provided by unpacking will be treated
> in exactly the same way as they are now: ones that match defined
> parameters are gather there and the remainder will be collected into the
> ordered kwargs (just like any other unmatched keyword argument).

There *is* a connection here: this needs to play nice with the ordered
kwargs in order to handle the pass-through case correctly.

The guarantee that the order of the supplied mapping (minus any
entries that map to named parameters) will be preserved needs to be
made explicit.

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia