Readie - 6:14 pm on Jun 29, 2010 (gmt 0)

Might be best to convert all square brackets to their html entity counterpart inside the "escape" tags first, and remove the escape tags. Then run the main part of the BB code script, like so:

while(preg_match('/\[esc\](.*?)\[\/esc\]/im', $input, $out)) {
  $repl = str_replace('[', '[', $out[1]);
  $repl = str_replace(']', ']', $repl);
  $input = str_replace($out[0], $repl, $input);
  unset($repl, $out);
}