Method error

src/json-validator.cpp:382–390

	std::string message_;

	void error(const json::json_pointer &ptr, const json &instance, const std::string &message) override
	{
		if (*this)
			return;
		error_ = true;
		ptr_ = ptr;
		instance_ = instance;
		message_ = message;
	}

	operator bool() const { return error_; }
};