protected function parenValue(&$out)
    {
        $s = $this->seek();

        $inParens = $this->inParens;

        if ($this->literal('(')) {
            if ($this->literal(')')) {
                $out = [Type::T_LIST, '', []];

                return true;
            }

            $this->inParens = true;

            if ($this->expression($exp) && $this->literal(')')) {
                $out = $exp;
                $this->inParens = $inParens;

                return true;
            }
        }

        $this->inParens = $inParens;
        $this->seek($s);

        return false;
    }