Hi Greg
Thank you, for your support for d[x=1, y=2] being valid syntax.
You ask if I have any use cases in mind for a general keyword key class
being part of standard Python. Good question.
Anyone who is experimenting with keyword keys would, I think, appreciate
having something they can use straight away. Thus, I think, any use case
for PEP 472 is also a use case for the general keyword class I'm
suggesting. No use cases for PEP 472 would of course be fatal.
Storing function call results would be a use case. For this, look at the
implementation of functools.lru_cache.
I am keen to develop, with others, examples of how PEP 472 could help us in
real-world programming. Even if convinced that PEP 472 is a good idea, the
examples would help us get the details right, and also help with formal and
informal documentation.
For a specific example, a simple ad hoc way of recording data. For example
>>> height[x=10, y=14] = 2010
We can already use dictionaries in this way, as in
>>> height[10, 14] = 2010
So this is a bit like using named tuples instead of tuples.
I think that's enough for now.
--
Jonathan
On Fri, Aug 14, 2020 at 12:28 PM Greg Ewing <greg.ew...@canterbury.ac.nz>
wrote:
> On 14/08/20 10:03 pm, Jonathan Fine wrote:
> > NO POSITIONAL ARGUMENTS
> > I'd like
> > >>> d[x=1, y=2]
> > to be valid syntax. It's not clear to me that all agree with this.
>
> If keywords are to be allowed, it seems reasonable to me
> that this should be legal.
>
> > >>> d[x=1, y=2] = 42
> > >>> d[x=1, y=2]
> > 42
> > >>> d[a='alpha', g='gamma', z=12] = 'cheese'
> > >>> d[a='alpha', g='gamma', z=12]
> > 'cheese'
> >
> > My question is this: Should such a class ... be part of standard Python,
>
> Do you have any use cases in mind for this?
>
> To justify being built in, it would need to have a wide range
> of uses.
>
> --
> Greg
>
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