if (!defined('T_ML_COMMENT')) {
   define('T_ML_COMMENT', T_COMMENT);
} else {
   define('T_DOC_COMMENT', T_ML_COMMENT);
}

$source = file_get_contents('example.php');
$tokens = token_get_all($source);

foreach ($tokens as $token) {
   if (is_string($token)) {
  echo $token;
   } else {
  list($id, $text) = $token;

       switch ($id) { 
           case T_COMMENT: 
           case T_ML_COMMENT: 
case T_DOC_COMMENT:
break;

           default:
  echo $text;
               break;
       }
   }
}
?>