public function filter($text, $config = array())
    {
        $context = $this->_chain->getContext();
        $context->data = $text;
        $context->config = $config;
        if ($context->config->filter) {
            $filter = (array) AnConfig::unbox($context->config->filter);
            $filter[] = 'ptag';
            $context->config->filter = $filter;
        }
        $this->_chain->run('filter', $context);

        return $context->data;
    }