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

use strict;

use efgh qw(do_thing);

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

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

for my $hash (@bar) {
    print "$_ => $hash->{$_}\n" for keys %$hash;
    print "\n";
}
scorpion:/export/home/kinyonro-> cat efgh.pm
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' => 'd'
          },
          {
            'blah' => 'b'
          },
          {
            'blah' => 'c'
          }
        ];
$VAR1 = {
          'blah' => 'd'
        };
$VAR2 = {
          'blah' => 'b'
        };
$VAR3 = {
          'blah' => 'c'
        };
blah => d

blah => b

blah => c