The primary issue I was trying to find a way to reliably and clearly avoid
conflicts between the index labels and the positional argument names. So
if you have:
__getitem__(self, index, **kwargs)
You can't have an index label named "index", because it conflicts with the
"index" positional argument.
Apparently that isn't an issue if you structure it like this instead:
__getitem__(self, index, /, **kwargs)
But projects would need to know to do that.
Also, as Greg alluded to, it is more consistent with how the indices are
handled currently, which is to use a single variable rather than positional
arguments. There may also be performance implications, although I am not
certain about that.
On Mon, Aug 3, 2020 at 9:36 PM Steven D'Aprano <st...@pearwood.info> wrote:
> On Mon, Aug 03, 2020 at 05:20:25PM -0400, Todd wrote:
> > Another approach could be too simply pass the labelled indices in a dict
> as
> > a third/fourth positional argument.
>
> Why would we want to even consider a new approach to handling keyword
> arguments which applies only to three dunder methods, `__getitem__`,
> `__setitem__` and `__delitem__`, instead of handling keyword arguments
> in the same way that every other method handles them?
>
> That's not a rhetorical question. If there is an advantage to making
> this a special case, instead of just following the same rules as all
> other methods, I'm open to hearing why it should be treated as a special
> case.
>
>
> > So for indexing
> >
> > b = arr[1, 2, a=3, b=4]
> >
> > Instead of
> >
> > __getitem__(self, (1, 2), a=3, b=4)
> >
> > Just do
> >
> > __getitem__(self, (1, 2), {'a': 3, 'b': 4})
>
> That would be the effect of defining your method with signature:
>
> def __getitem__(self, index, **kwargs)
>
> so if you specifically want all your keyword arguments bundled into a
> dict, you can easily get it.
>
>
>
> --
> Steven
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