> On 8 Oct 2019, at 20:49, Todd <toddr...@gmail.com> wrote:
>
>
>> On Tue, Oct 8, 2019 at 2:18 PM Anders Hovmöller <bo...@killingar.net> wrote:
>>
>>
>>>> On 8 Oct 2019, at 20:07, Todd <toddr...@gmail.com> wrote:
>>>>
>>>
>>>
>>>> On Tue, Oct 8, 2019 at 1:30 PM Anders Hovmöller <bo...@killingar.net>
>>>> wrote:
>>>>
>>>>
>>>>>> On 8 Oct 2019, at 19:19, Caleb Donovick <donov...@cs.stanford.edu> wrote:
>>>>>>
>>>>>
>>>>>> Because
>>>>>>
>>>>>> >>> dict(foo=:1)
>>>>>> File "<string>", line 1
>>>>>> dict(foo=:1)
>>>>>> ^
>>>>>> SyntaxError: invalid syntax
>>>>>
>>>>> I don't see how that's an argument, we are talking about a syntax
>>>>> extension. Slice builder syntax is only every allowed in a subscript.
>>>>> Edit my original grammar change proposal to:
>>>>>
>>>>> ```
>>>>> subscriptlist: ... | kwargsubscript (',' kwargsubscript )* [',']
>>>>> kwargsubscript: NAME '=' subscript
>>>>> ```
>>>>>
>>>>> Now slices are allowed in keyword arguments.
>>>>
>>>> I wasn't making an argument, I was wondering what exactly we are even
>>>> discussing. It seems like people are inventing new syntax willy nilly in
>>>> this thread and I am getting very confused :)
>>>>
>>>> / Anders
>>>>
>>>
>>> I thought we were talking about allowing __getitem__ to support keywords.
>>> I assumed the keywords would use the same syntax as positional values, and
>>> converting colons to slice objects is part of that syntax. So this isn't
>>> new syntax, it is just making the positional and keyword syntaxes the same.
>>
>> I don't see it. Can you give examples of all the variations of slicing and
>> their keyword equivalent so I understand what you mean? I'll write out the
>> slicing variants and you can fill in how it would look with keyword
>> arguments:
>>
>> x[:]
>> x[a:]
>> x[-a:]
>> x[a:b]
>> x[-a:b]
>> x[a:-b]
>> x[-a:-b]
>> x[:b]
>> x[:-b]
>>
>>
>
> The colon operation would be converted to slices identically to how it is
> with positional arguments, it is just that those slices would assigned to
> values in a dict (or some other mapping) instead of values in a tuple.
> Otherwise it would work exactly the same.
>
> x[:] is x[slice(None, None)]
> x[foo=:] is x[foo=slice(None, None)]
>
> x[a:] is x[slice(a, None)]
> x[foo=a:] is x[foo=slice(a, None)]
>
> x[-a:] is x[slice(-a, None)]
> x[foo=-a:] is x[foo=slice(-a, None)]
>
> x[a:b] is x[slice(a, b)]
> x[foo=a:b] is x[foo=slice(a, b)]
>
> x[-a:b] is x[slice(-a, b)]
> x[foo=-a:b] is x[foo=slice(-a, b)]
>
> x[a:-b] is x[slice(a, -b)]
> x[foo=a:-b] is x[foo=slice(a, -b)]
>
> x[-a:-b] is x[slice(-a, -b)]
> x[foo=-a:-b] is x[foo=slice(-a, -b)]
>
> x[:b] is x[slice(None, b)]
> x[foo=:b] is x[foo=slice(None, b)]
>
> x[:-b] is x[slice(None, -b)]
> x[foo=:-b] is x[foo=slice(None, -b)]
>
> If you look at multiple indices,
>
> x[a, -b:c] is x[a, slice(-b, c)]
> x[foo=a, bar=-b:c] is x[foo=a, bar=slice(-b, c)
Aaaah. Now I see it. Thanks for clarifying that for me.
_______________________________________________
Python-ideas mailing list -- python-ideas@python.org
To unsubscribe send an email to python-ideas-le...@python.org
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at
https://mail.python.org/archives/list/python-ideas@python.org/message/KNHUWPG2E7ZZEROGELIC6T2RO43FQTEZ/
Code of Conduct: http://python.org/psf/codeofconduct/
