Function operator<

3rd/nlohmann_json/include/nlohmann/json.hpp:6531–6603

! @brief comparison: less than Compares whether one JSON value @a lhs is less than another JSON value @a rhs according to the following rules: - If @a lhs and @a rhs have the same type, the values are compared using the default `<` operator. - Integer and floating-point numbers are automatically converted before comparison - In case @a lhs and @a rhs have diffe

    @since version 1.0.0
    */
    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
    {
        const auto lhs_type = lhs.type();
        const auto rhs_type = rhs.type();

        if (lhs_type == rhs_type)
        {
            switch (lhs_type)
            {
                case value_t::array:
                    // note parentheses are necessary, see
                    // https://github.com/nlohmann/json/issues/1530
                    return (*lhs.m_value.array) < (*rhs.m_value.array);

                case value_t::object:
                    return (*lhs.m_value.object) < (*rhs.m_value.object);

                case value_t::null:
                    return false;

                case value_t::string:
                    return (*lhs.m_value.string) < (*rhs.m_value.string);

                case value_t::boolean:
                    return (lhs.m_value.boolean) < (rhs.m_value.boolean);

                case value_t::number_integer:
                    return (lhs.m_value.number_integer) < (rhs.m_value.number_integer);

                case value_t::number_unsigned:
                    return (lhs.m_value.number_unsigned) < (rhs.m_value.number_unsigned);

                case value_t::number_float:
                    return (lhs.m_value.number_float) < (rhs.m_value.number_float);

                case value_t::binary:
                    return (*lhs.m_value.binary) < (*rhs.m_value.binary);

                case value_t::discarded:
                default:
                    return false;
            }
        }
        else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_float)
        {
            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
        }
        else if (lhs_type == value_t::number_float && rhs_type == value_t::number_integer)
        {
            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
        }
        else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_float)
        {
            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
        }
        else if (lhs_type == value_t::number_float && rhs_type == value_t::number_unsigned)
        {
            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);