Function operator<

native/thirdpart/json/json.hpp:2877–2888

! @brief comparison operator for JSON types Returns an ordering that is similar to Python: - order: null < boolean < number < object < array < string - furthermore, each type is not smaller than itself - discarded values are not comparable @since version 1.0.0 */

@since version 1.0.0
*/
inline bool operator<(const value_t lhs, const value_t rhs) noexcept
{
    static constexpr std::array<std::uint8_t, 8> order = {{
            0 /* null */, 3 /* object */, 4 /* array */, 5 /* string */,
            1 /* boolean */, 2 /* integer */, 2 /* unsigned */, 2 /* float */
        }
    };

    const auto l_index = static_cast<std::size_t>(lhs);
    const auto r_index = static_cast<std::size_t>(rhs);
    return l_index < order.size() and r_index < order.size() and order[l_index] < order[r_index];
}
}  // namespace detail
}  // namespace nlohmann