public function direction()
    {
        if (empty($this->direction)) {
            $rtlScripts = ['Arab', 'Hebr', 'Mong', 'Tfng', 'Thaa'];

            $this->setDirection(
                in_array($this->script, $rtlScripts)
                    ? self::DIRECTION_RIGHT_TO_LEFT
                    : self::DIRECTION_LEFT_TO_RIGHT
            );
        }

        return $this->direction;
    }