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Postings from December 2022
[ resend, sent it to Paul instead of p5p, sorry Paul ]
Op 02-12-2022 om 18:38 schreef Paul "LeoNerd" Evans:
> * The `in` meta-operator
> https://metacpan.org/pod/Syntax::Operator::In
>
> One thing people liked to use `~~` for is to ask "is this value a
> member of that list of values?"; a sortof set-element-of operator.
> While it's been possible to ask this question using List::Util::any
> ever since perl 5.6 (and likely before - I don't remember that far
> back in time), people still aren't satisfied with that notation:
>
> if($x ~~ @numbers) { ... }
> if(any { $x == $_ } @numbers) { ... }
>
> For those folks, I have written an `in` meta-operator. Motivated in
> much the same way as match/case above, there can be no ambiguity on
> "is this matching with number or string equality here?" because it
> says right upfront in the operator name itself. You tell it - `==`
> or `eq`.
>
> if($x in:== @numbers) { ... }
A thought occured to me of a possible problem here. Consider:
$its_in = $needle in:=~ qr/haystack/;
v.s.
$its_in = $needle in:< @haystack;
Wouldn't the first to be the RHS of the op, and the second the LHS?
Wouldn't this create a problem? Or do I simply misunderstand?
M4
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