PCHR = ["K", "Q", "R", "B", "N", "P"]
  w1 = "QRKPNB"
  w2 = "".join(sorted(w1, key=PCHR.index)) # Translate this to Perl ...
  print(w1 + " -> " + w2)

##</code><code>##

  my $i = 0;
  use constant PCHR => split //, 'KQRBNP';
  my %pchr = map { $_ => $i++ } PCHR;
  my $w1 = 'QRKPNB';
  my $w2 = join '', sort { $pchr{$a} <=> $pchr{$b} } split //, $w1;
  print "$w1 -> $w2\n";