PHP code line numbering

I have put a little addition into the filter module to add line numbers to PHP code blocks.

It uses OL and LI tags to add the line numbers, replace the entire _bbcode_php_tag function with the one below:

function _bbcode_php_tag($text = NULL) {             
  $text_source = explode("\n", $text);
  foreach ($text_source as $this_line)
  {
      $output_code .= '<li>';
    
      if (ereg('<\?(php)?[^[:graph:]]', $this_line))
          $output_code .= str_replace(array('<code>', '

', "\n", '
'), '', highlight_string($this_line, true)) . '

';
else
$output_code .= ereg_replace('(<\?php )+', '', str_replace(array('', '', "\n", '
'), '', highlight_string('<?php '.$this_line, true))) . '

';
}
$return = '

'.$output_code.'

';
return $return;
}

This can probable be scaled down a bit, but it works for my needs.