Class iteration_proxy_value

Source/Utils/json.hpp:3841–3926

            target = to_string(value);
        }
        template<typename IteratorType> class iteration_proxy_value
        {
        public:
            using difference_type = std::ptrdiff_t;
            using value_type = iteration_proxy_value;
            using pointer = value_type*;
            using reference = value_type&;
            using iterator_category = std::input_iterator_tag;
            using string_type = typename std::remove_cv< typename std::remove_reference<decltype(std::declval<IteratorType>().key()) >::type >::type;

        private:
            /// the iterator
            IteratorType anchor;
            /// an index for arrays (used to create key names)
            std::size_t array_index = 0;
            /// last stringified array index
            mutable std::size_t array_index_last = 0;
            /// a string representation of the array index
            mutable string_type array_index_str = "0";
            /// an empty string (to return a reference for primitive values)
            const string_type empty_str = "";

        public:
            explicit iteration_proxy_value(IteratorType it) noexcept : anchor(it) {}

            /// dereference operator (needed for range-based for)
            iteration_proxy_value& operator*()
            {
                return *this;
            }

            /// increment operator (needed for range-based for)
            iteration_proxy_value& operator++()
            {
                ++anchor;
                ++array_index;

                return *this;
            }

            /// equality operator (needed for InputIterator)
            bool operator==(const iteration_proxy_value& o) const
            {
                return anchor == o.anchor;
            }

            /// inequality operator (needed for range-based for)
            bool operator!=(const iteration_proxy_value& o) const
            {
                return anchor != o.anchor;
            }

            /// return key of the iterator
            const string_type& key() const
            {
                JSON_ASSERT(anchor.m_object != nullptr);

                switch (anchor.m_object->type())