On 2020-11-12 19:21, Paul Sokolovsky wrote:
Hello,
[Re-routed back to python-dev.]
On Thu, 12 Nov 2020 20:04:57 +0100
Piotr Duda <duda.pi...@gmail.com> wrote:
[]
> match foo:
> case ("foo", >val1):
> ...
> case ("bar", >val2):
> ...
>
I agree with that, though I would prefer using other symbol than > (?
or $), one of reasons would by it would look better as "match all"
target, other one that in future. it would allow extending syntax for
simple guards like ?x < 100.
Question of "what to mark with sigils - terms-used-as-values or
terms-used-for-capturing" is orthogonal to the question of "what to use
as match-all symbol", though I understand the desire to repurpose the
same symbol for both.
For a capturing sigil, "->", ">", ">>", "@", "?", "$" already were or
can be proposed. The benefit of "->", ">", ">>" is that they're very
intuitive. I'd also have preference for shorter one, because 2-chars
are really verbose IMHO. OTOH, ">" has issue with parsing ambiguity
unless separated by spaces ("Cls(kw1=>var)"). "$" is the worst choice
IMHO, because intuitively (based on other languages - shell, etc.) it
says "use the value of variable".
I'd still want to list "as" as another possibility, the advantage being
that it's already used for binding elsewhere.
That said, those are 2nd-level choices. The current stage is to accept
the fact that "mark capturing terms" is *very viable* alternative to
"mark terms to use as values" (3rd choices - "use adhoc interpretation
of non-orthogonal syntactic conventions" - being the worst). But people
behind PEPs keep ignoring that choice - silently, or with minimal
consideration/commentary.
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