Frontend\Core\Engine\SeoFormTokenParser::parse PHP Метод

    public function parse(\Twig_Token $token)
    {
        $stream = $this->parser->getStream();
        if ($stream->getCurrent()->getType() != \Twig_Token::BLOCK_END_TYPE) {
            $error = sprintf("'%s' does not require any arguments.", $this->getTag());
            throw new \Twig_Error_Syntax($error, $token->getLine(), $this->parser->getFilename());
        }
        $stream->expect(\Twig_Token::BLOCK_END_TYPE);
        if (FormState::$current === null) {
            throw new \Twig_Error_Syntax(sprintf('Cannot render seo outside a form element'), $token->getLine(), $this->parser->getFilename());
        }
        return new SeoFormNode(FormState::$current, $token->getLine(), $this->getTag());
    }