wordsearch-degolfed.pl

$\="\n"; # "print for ..." at the end puts stuff on new lines :)
$/=""; # paragraph mode.
@word = split//,pop; # Get the search word off of the commandline
($board=<>) =~ tr/ //d;
$width = 1 + index($board, "\n"); # How wide is the board? Find the first newline.
for (1,2) {
  # Find the word forwards, southwest, south, and southeast.
  for my $stride (0, $width - 2 .. $width) {
    $pattern = join "."x $stride, @word;
    # If it's in the board, record the start and end match positions.
    push @matches, [ $-[0], $+[0] - 1] while $board =~ /$pattern/sg;
  }
  # Reverse the word, so that on the next iter we find the word backwards,
  # northeast, north, and northwest.
  @word = reverse @word;
  # And reverse the starts and ends. The forward matches will be reversed
  # twice (and come out forwards); the backward ones will only be reversed
  # once.
  @matches = map [ reverse @$_ ], @matches;
}

sub pos_to_row_col {
  my $pos = shift;
  return sprintf "row %d, column %d",
    (1 + $pos / $width),
    (1 + $pos % $width);
}

for my $match (@matches) {
  print pos_to_row_col( $match->[0] ) . " --> "
    . pos_to_row_col( $match->[1] );
}