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Postings from August 2012
On Thu, Aug 16, 2012 at 05:58:16PM -0400, Ricardo Signes wrote:
>
> So, last year I said "we really ought to cut most of smart match away."
>
> http://www.nntp.perl.org/group/perl.perl5.porters/2011/07/msg174272.html
>
> I've slept on it about 380 times, and I'm still for it. Here's the new plan:
>
> ## The New ~~ Operator
>
> $a $b Meaning
> ======= ======= ======================
> Any undef ! defined $a
> Any ~~-overloaded ~~ overloading is used
> ~~-ol Any ~~ overloading is used (reversed)
> Any CodeRef, &{}-ol $b->($a)
> Any Regexp, qr-ol $a =~ $b
> Any Simple $a eq $b
> Any Any fatal
>
> This is a nearly a subset of the current behavior. Here are some major points:
>
> (1) This is ordered for the sake of knowing which overload to use first.
>
> (2) A simple scalar (non-reference, non-glob, non-vstring) on the rhs is
> used for stringwise equality. I have not yet seen any convincing argument
> that we can correctly intuit an eq/== behavior, so we pick one.
For me, one of the few advantages I saw in using ~~ is not having to
wonder when to use == vs eq vs =~. The above table suggests that
"0.0" ~~ 0
is false, while it's currently true. That bothers me. IMO, a "smart match"
should be able to say, "hmmm, both my operands look like numbers, you know
what, I'll use '==' to compare them!"
Would this be workable:
$a $b Meaning
======= ======= ======================
Any undef ! defined $a
Any ~~-overloaded ~~ overloading is used
~~-ol Any ~~ overloading is used (reversed)
Any CodeRef, &{}-ol $b->($a)
Any Regexp, qr-ol $a =~ $b
Any Looks like number $a == $b (without a "isn't numeric" warning)
Any Simple $a eq $b
Any Any fatal
Abigail
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