protected function _url($url = null) {
		if ($url !== null) {
			return '/' . trim($url, '/');
		} elseif ($uri = $this->env('REQUEST_URI')) {
			list($uri) = explode('?', $uri, 2);
			$base = '/^' . preg_quote($this->_base, '/') . '/';
			return '/' . trim(preg_replace($base, '', $uri), '/') ?: '/';
		}
		return '/';
	}