On Mon, Aug 24, 2020 at 12:54 AM Random832 <random832@fastmail.com> wrote:
> Why not allow slice syntax as an expression everywhere?
 
is {a:b} a set containing a slice, or a dict? obviously it's a dict, but are there any other places that might be affected?

should we support {a, b:c} as a set containing a slice? what about {a:b, c}?

well, slices aren't hashable, so no. though technically hashabily is not a syntax issue. So if a:b:c was a valid expressson anywhere, then you should be able to *try* putting in in a set ...

but {a:b:1} is now a syntax error, so we could make only the three-part form allowable.
 
there may be other places it might be desirable to add new syntax that uses the colon character, allowing slices anywhere would foreclose that.

well, not sure I agree that that's a strong motivator.

I do think the dict display issue is big one though. But maybe we could expand where slices can be used, like function calls, for instance:

though *maybe* there would be less use for that if.when we get keywords in the [] operator.

-CHB


 
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