public function toJson()
    {
        $this->parse();
        $j = array();
        foreach ($this->_options as $flag => $value) {
            $j['options'][] = array(
                'option' => array(
                    'flag' => $flag,
                    'parameter' => $value
                )
            );
        }

        /**
         * @see Zend_Json
         */
        require_once 'Zend/Json.php';
        $json = Zend_Json::encode($j);

        return $json;
    }