use strict;
use warnings;

sub compare {
        my ($a, $b) = @_;
        my $rand = rand();
        print "$a: $rand; $b: 0.5\n";
        return $rand <=> 0.5;
}

print join "", sort { compare($a, $b) } split //, "abcde";

##</code><code>##

$ perl test.pl
a: 0.876941476789401; b: 0.5
c: 0.0768385185833438; d: 0.5
b: 0.203632482365844; c: 0.5
c: 0.234952540459695; a: 0.5
a: 0.746254431212112; d: 0.5
b: 0.648884088019244; e: 0.5
ebcda