public static function highlight_string($source, $language, $return = false, $opts = 0)
    {
        if (is_int($return)) {
            $opts = $return;
            $return = false;
        }

        $gs = new static($source, $language, $opts);
        $s = $gs->parseCode();

        if ($gs->error()) {
            return false;
        }

        if ($return) {
            return '<code>' . $s . '</code>';
        }
        echo '<code>' . $s . '</code>';

        return true;
    }