On Mon, Jun 24, 2019 at 2:44 PM Andrew Barnert via Python-ideas
<python-ideas@python.org> wrote:
> But dict displays, that could be confusing. Do you have to pass-value the 
> key, or the value, or either of the two, or both consistently? If the key, 
> does that short-circuit the value expression? So I think you’re right, that’s 
> possibly worth banning even if you have to go out of your way to do so.
>

I think if this could be made to work for list displays and function
arguments, it wouldn't be too hard to settle the semantics for a dict.
My personal shed colour would be: omit the key and the value won't be
evaluated; omit either to suppress the result. But there are other
valid semantics, and it'd just be a matter of picking something sane.

The biggest problem with this proposal is the way that, being a
syntactic construct, it's going to be non-composable.

# Oops, syntax error
with (some_expr as q,
        some_other_expr as w):
    pass

ChrisA
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