my $it1 = $fp->next_parseable_file;
    while (my $file1 = $it1->next) {
      print $fp->short_name($file1) . "\n";
      my $it2 = $fp->next_nonparseable_file;
      while (my $file2 = $it2->next) {
        print $fp->short_name($file2) . "\n";
      }
    }