sub shuffle (@) {
  my @a=\(@_);
  my $n;
  my $i=@_;
  map {
    $n = rand($i--);
    (${$a[$n]}, $a[$n] = $a[$i])[0];
  } @_;
}

##</code><code>##

#!/usr/bin/perl

use strict;
use warnings;
use Benchmark qw/:all :hireswallclock/;

sub naive (@) {
    my @l=@_;
    for (reverse 1..$#l) {
        my $r=int rand($_+1);
        @l[$_,$r]=@l[$r,$_];
    }
    @l;
}

sub listutil (@) {
    my @a=\(@_);
    my $n;
    my $i=@_;
    map {
        $n = rand($i--);
        (${$a[$n]}, $a[$n] = $a[$i])[0];
    } @_;
}

cmpthese -60, { map { $_ => "$_ 1..1000" } qw/naive listutil/ };

__END__

##</code><code>##

C:\temp>perl lus.pl
          Rate    naive listutil
naive    588/s       --     -14%
listutil 684/s      16%       --