> On 6 Oct 2021, at 12:06, Larry Hastings <la...@hastings.org> wrote: > > It seems like, for this to work, "group" would have to become a keyword. > No, just like `match` and `case` didn't have to.
> This would play havoc with a lot of existing code.
>
Extraordinary claims require extraordinary evidence, Larry. I maintain this
will be entirely backwards compatible.
> Even making it a soft keyword, a la "await" in 3.5, would lead to ambiguity:
>
> group = KeyboardInterrupt
>
> try:
> while True:
> print("thou can only defeat me with Ctrl-C")
> except group as error:
> print("lo, thou hast defeated me")
>
Two things:
1. This is a convoluted example, I bet $100 you won't find such an `except
group` statement in any code predating my e-mail 🤠 Sure, sometimes (very
rarely) it's useful to gather exceptions in a variable. But I'm pretty sure
`group` won't be the name chosen for it.
2. While non-obvious, the example is not ambiguous. There can only be one
parsing rule fitting this:
'except' expression 'as' NAME ':'
Note how this is different from:
'except' 'group' expression 'as' NAME ':'
There could be confusion if except-star, whatever its name is going to be,
supported an empty "catch all" variant like `except:`. Thankfully, this is
explicitly listed as a no-go in PEP 654. So `except group:` remains
unambiguous. We can even make its error message smarter than the default
NameError, since -- as I claim -- it's terribly unlikely somebody would mean to
name their dynamic exception collection "group".
- Ł
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