function _invokeParser($content, $is_match) {
            if (($content === "") || ($content === false)) {
                return true;
            }
            $handler = $this->_mode->getCurrent();
            if (isset($this->_mode_handlers[$handler])) {
                $handler = $this->_mode_handlers[$handler];
            }
            return $this->_parser->$handler($content, $is_match);
        }