On Thu, Aug 27, 2020 at 07:24:01AM -0400, Ricky Teachey wrote:
> It kills at least 3 birds with one stone:
>
> 1. Brings kwd arguments to item dunders (PEP 472 does this too, but a
> key/index translation dunder kills two other birds)
I would put it another way: your proposal to redesign subscripting is
independent of whether or not keyword subscripts are permitted. We could
redesign the comma-separated item part of it without introducing
keywords at all.
There is nothing in your proposal that requires keywords. Just delete
the bits about `**kwargs` and the rest of it stands as it is.
PEP 472, on the other hand, is *all about keywords*. Keywords are
irrelevant to your proposal to redesign subscripting. We could take it
with or without keywords.
> 2. Switches positional arguments over to the function paradigm, bringing
> the full power of python signature parsing to subscripting.
If you want a function call, use function call syntax. PEP 472 is about
adding keyword support to subscripting. The aim of the PEP is still for
subscripting to fundamentally be about an index or key, not about making
square brackets to be a second way to do function calls. I'll have more
to say about that later.
> 3. Removes the need to write calls to the same supporting function in the
> item dunders. They are called automatically.
I don't understand that sentence.
[...]
> My current attempt is this:
>
> def __subscript__(self, *args, **kwargs) -> Tuple [Tuple[Any], Dict[str,
> Any]]:
> return t
NameError: name 't' is not defined
> Which, for a getitem dunder call, `t` becomes:
>
> obj.__getitem__(*t[0], **t[1])
What does this mean? You assign
t = obj.__getitem__(*t[0], **t[1])
and then return t?
--
Steve
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