Re: plperl & sort

On Tue, Nov 4, 2008 at 12:39, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> "Alex Hunsaker" <badalex(at)gmail(dot)com> writes:
>> Hrm works for me if I take out the elog from sort()
>
> Even more interesting, this variant *doesn't* work:
>
> regression=# create or replace function trustedsort()
> returns int
> as $$
> my @arr = qw(5 4 3 2 1);
> my @sorted = sort { "$a" <=> "$b" } @arr;
> elog(NOTICE, join(' ', @sorted));
> return 1;
> $$
> language 'plperl';
> CREATE FUNCTION
> regression=# select trustedsort();
> NOTICE: 5 4 3 2 1
> trustedsort
> -------------
> 1
> (1 row)
>
> Seems like it's the interpolation into a string that is failing.

It has something to do with anon subs not sure what...
see below test case

This works:

require Safe;

my $safe = Safe->new('PLPerl');
$safe->permit_only(':default');
$safe->permit(qw(sort));
$safe->share(qw(&j));

sub j
{
print "j called ". (shift) . "\n";
}

my $f = $safe->reval(<<'z');
sub blah {
my @c = sort { j("$a $b"); $a <=> $b } qw(5 4 3 2 1);
j(join(" ", @c));
return;
}

blah();
z

$ perl tsafe.pl
j called 5 4
j called 3 2
j called 4 2
j called 4 3
j called 2 1
j called 1 2 3 4 5

This fails: (which is what we do in plperl.c)
my $f = $safe->reval(<<'z');
sub {
my @c = sort { j("$a $b"); $a <=> $b } qw(5 4 3 2 1);
j(join(" ", @c));
return;
}
z

$f->();

$ perl tsafe.pl
j called
j called
j called
j called
j called
j called
j called
j called
j called 5 4 3 2 1

This works:
$safe->reval(<<'z');
my @c = sort { j("$a $b"); $a <=> $b } qw(5 4 3 2 1);
j(join(" ", @c));
return;
z

$ perl tsafe.pl
j called 5 4
j called 3 2
j called 4 2
j called 4 3
j called 2 1
j called 1 2 3 4 5

Dunno...