public function slug($var = null)
    {
        if ($var !== null && $var !== '') {
            $this->slug = $var;
        }

        if (empty($this->slug)) {
            $this->slug = $this->adjustRouteCase(preg_replace(PAGE_ORDER_PREFIX_REGEX, '', $this->folder)) ?: null;
        }

        return $this->slug;
    }