Method operator()

Source/Utils/json.hpp:3787–3792

        {
            template<typename BasicJsonType, typename T>
            auto operator()(const BasicJsonType& j, T& val) const
                noexcept(noexcept(from_json(j, val)))
                -> decltype(from_json(j, val), void())
            {
                return from_json(j, val);
            }
        };
    }  // namespace detail