public static function filterCommentless($content, $callback)
    {
        $result = '';
        foreach (preg_split(static::REGEX_COMMENTS, $content, -1, PREG_SPLIT_DELIM_CAPTURE) as $part) {
            if (!preg_match(static::REGEX_COMMENTS, $part, $match) || $part != $match[0]) {
                $part = call_user_func($callback, $part);
            }

            $result .= $part;
        }

        return $result;
    }