[Python-Dev] Any grammar experts?

[Petr Viktorin]

On Mon, Jan 26, 2015 at 8:29 PM, Ethan Furman <ethan at stoneleaf.us> wrote:
> On 01/26/2015 11:24 AM, Barry Warsaw wrote:
>> On Jan 26, 2015, at 10:55 AM, Ethan Furman wrote:
>>
>>> In the your example
>>>
>>>  from_env = {'a': 12}
>>>  from_config = {'a': 13}
>>>
>>>  f(**from_env, **from_config)
>>>
>>> I would think 'a' should be 13, as from_config is processed /after/ from_env.
>>>
>>> So which is it?
>>
>> In the face of ambiguity, refuse the temptation to guess.
>
> Lots of things are ambiguous until one learns the rules.  ;)

I don't see why `f(**{'a': 12}, **{'a': 13})` should not be equivalent
to `f(a=12, **{'a':13})` – iow, raise TypeError.