# Untested :(
sub dedup {
  my $ref = shift;
  my %seen;
  my $c = 0; # current
  my $n = 0; # next available slot
  foreach (@$ref) {
    if (not $seen{$_}++) {
      $ref->[$n] = $_ unless $n == $c;
      $n++;
    }
    $c++;
  }
  $#{$ref} = $n-1;
}