scorpion:/export/home/kinyonro-> cat abcd
#!/usr/local/bin/perl

use strict;
use 5.6.0;

use efgh qw(do_thing);


###############################################################################


my $foo = [ [ { blah => 'a' }, {blah => 'b'}, ],
            [ { blah => 'e' }, {blah => 'f'}, ],
            [ { blah => 'c' }, {blah => 'd'}, ],
          ];
my $sortfunc = sub { $a->[0]->{blah} cmp $b->[0]->{blah} };

my @bar = do_thing($foo, $sortfunc);

for my $lref (@bar) {
    for my $hash (@$lref) {
        print "$_ => $hash->{$_}\n" for keys %$hash;
    }
    print "\n";
}


###############################################################################


$foo = [ { blah => 'd' }, { blah => 'b' }, { blah => 'c' }, ];
$sortfunc = sub { $a->{blah} cmp $b->{blah} };

@bar = do_thing($foo, $sortfunc);

for my $hash (@bar) {
    print "$_ => $hash->{$_}\n" for keys %$hash;
    print "\n";
}



scorpion:/export/home/kinyonro-> cat efgh.pm
use strict;
use 5.6.0;

package efgh;

use Exporter;
our @ISA = qw(Exporter);

our @EXPORT_OK = qw(do_thing);

use Data::Dumper;

sub do_thing {
    my ($data, $func) = @_;

print Data::Dumper->Dump([$data]);
    my @bar = sort $func @$data;
print Data::Dumper->Dump([@bar]);

    return @bar;
}

1;



scorpion:/export/home/kinyonro-> abcd
$VAR1 = [
          [
            {
              'blah' => 'a'
            },
            {
              'blah' => 'b'
            }
          ],
          [
            {
              'blah' => 'e'
            },
            {
              'blah' => 'f'
            }
          ],
          [
            {
              'blah' => 'c'
            },
            {
              'blah' => 'd'
            }
          ]
        ];
$VAR1 = [
          {
            'blah' => 'a'
          },
          {
            'blah' => 'b'
          }
        ];
$VAR2 = [
          {
            'blah' => 'e'
          },
          {
            'blah' => 'f'
          }
        ];
$VAR3 = [
          {
            'blah' => 'c'
          },
          {
            'blah' => 'd'
          }
        ];
blah => a
blah => b

blah => e
blah => f

blah => c
blah => d

$VAR1 = [
          {
            'blah' => 'd'
          },
          {
            'blah' => 'b'
          },
          {
            'blah' => 'c'
          }
        ];
No such pseudo-hash field "blah" at abcd line 32.