my @oldarray = (0..9);

my @array = sort {
    my $result = ($a cmp $b);
    print "$result ";
    $result
    } @oldarray;

print "\n@array\n";

##</code><code>##

-1 -1 -1 -1 -1 -1 1 -1 1 1 1 -1 1 -1 1 1 1 1 1 
0 1 2 3 4 5 6 7 8 9