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 <steve@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.
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