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Postings from July 2013
On Thu, Aug 1, 2013 at 1:35 AM, Ricardo SIGNES via RT
<perlbug-followup@perl.org> wrote:
> On Tue Jul 30 16:05:09 2013, sprout wrote:
>> In short: closures close over variables, not lexical scopes, unless
>> string eval is involved. (So one can work around this by including eval
>> "" in the sub.)
>
> When did this become true in practice?
>
> It does not match up with what I take to be common definition of closures as enclosing a
> complete environment. I agree that PadWalker is letting Perl programmers go beyond the realm
> of polite behavior, but let's put that aside.
>
> Why shouldn't this program be able to print 2?
>
> use 5.12.0;
> use PadWalker 'peek_my';
>
> my $x = 1;
>
> use Data::Dumper;
>
> my $z = sub {
> warn Dumper(peek_my(1));
> eval { ${ peek_my(1)->{'$x'} } = 2 }
> };
>
> my $w = sub { $z->() };
>
> $w->();
>
> say $x;
>
> What are the practical wins to making closure per-variable instead of per-environment?
See also #89544
Leon
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