[Python-Dev] (no subject)

[Georg Brandl]

On 02/10/2015 10:33 AM, Paul Moore wrote:
> On 10 February 2015 at 00:29, Neil Girdhar <mistersheik at gmail.com> wrote:
>>> > function(**kw_arguments, **more_arguments)
>>> If the key "key1" is in both dictionaries, more_arguments wins, right?
>>
>>
>> There was some debate and it was decided that duplicate keyword arguments
>> would remain an error (for now at least).  If you want to merge the
>> dictionaries with overriding, then you can still do:
>>
>> function(**{**kw_arguments, **more_arguments})
>>
>> because **-unpacking in dicts overrides as you guessed.
> 
> Eww. Seriously, function(**{**kw_arguments, **more_arguments}) feels
> more like a Perl "executable line noise" construct than anything I'd
> ever want to see in Python. And taking something that doesn't work and
> saying you can make it work by wrapping **{...} round it just seems
> wrong.

I don't think people would want to write the above.

I like the "sequence and dict flattening" part of the PEP, mostly because it
is consistent and should be easy to understand, but the comprehension syntax
enhancements seem to be bad for readability and "comprehending" what the code
does.

The call syntax part is a mixed bag: on the one hand it is nice to be
consistent with the extended possibilities in literals (flattening),
but on the other hand there would be small but annoying inconsistencies
anyways (e.g. the duplicate kwarg case above).

Georg