move primitive_iterator outside of basic_json

src/json.hpp

@@ -3569,6 +3569,152 @@ class parser
     /// possible reason for the syntax error
     token_type expected = token_type::uninitialized;
 };
+
+///////////////
+// iterators //
+///////////////
+
+/*!
+@brief an iterator for primitive JSON types
+
+This class models an iterator for primitive JSON types (boolean, number,
+string). It's only purpose is to allow the iterator/const_iterator classes
+to "iterate" over primitive values. Internally, the iterator is modeled by
+a `difference_type` variable. Value begin_value (`0`) models the begin,
+end_value (`1`) models past the end.
+*/
+class primitive_iterator_t
+{
+  public:
+    using difference_type = std::ptrdiff_t;
+
+    difference_type get_value() const noexcept
+    {
+        return m_it;
+    }
+    /// set iterator to a defined beginning
+    void set_begin() noexcept
+    {
+        m_it = begin_value;
+    }
+
+    /// set iterator to a defined past the end
+    void set_end() noexcept
+    {
+        m_it = end_value;
+    }
+
+    /// return whether the iterator can be dereferenced
+    constexpr bool is_begin() const noexcept
+    {
+        return (m_it == begin_value);
+    }
+
+    /// return whether the iterator is at end
+    constexpr bool is_end() const noexcept
+    {
+        return (m_it == end_value);
+    }
+
+    friend constexpr bool operator==(primitive_iterator_t lhs,
+                                     primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it == rhs.m_it;
+    }
+
+    friend constexpr bool operator!=(primitive_iterator_t lhs,
+                                     primitive_iterator_t rhs) noexcept
+    {
+        return !(lhs == rhs);
+    }
+
+    friend constexpr bool operator<(primitive_iterator_t lhs,
+                                    primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it < rhs.m_it;
+    }
+
+    friend constexpr bool operator<=(primitive_iterator_t lhs,
+                                     primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it <= rhs.m_it;
+    }
+
+    friend constexpr bool operator>(primitive_iterator_t lhs,
+                                    primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it > rhs.m_it;
+    }
+
+    friend constexpr bool operator>=(primitive_iterator_t lhs,
+                                     primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it >= rhs.m_it;
+    }
+
+    primitive_iterator_t operator+(difference_type i)
+    {
+        auto result = *this;
+        result += i;
+        return result;
+    }
+
+    friend constexpr difference_type
+    operator-(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it - rhs.m_it;
+    }
+
+    friend std::ostream& operator<<(std::ostream& os, primitive_iterator_t it)
+    {
+        return os << it.m_it;
+    }
+
+    primitive_iterator_t& operator++()
+    {
+        ++m_it;
+        return *this;
+    }
+
+    primitive_iterator_t operator++(int)
+    {
+        auto result = *this;
+        m_it++;
+        return result;
+    }
+
+    primitive_iterator_t& operator--()
+    {
+        --m_it;
+        return *this;
+    }
+
+    primitive_iterator_t operator--(int)
+    {
+        auto result = *this;
+        m_it--;
+        return result;
+    }
+
+    primitive_iterator_t& operator+=(difference_type n)
+    {
+        m_it += n;
+        return *this;
+    }
+
+    primitive_iterator_t& operator-=(difference_type n)
+    {
+        m_it -= n;
+        return *this;
+    }
+
+  private:
+    static constexpr difference_type begin_value = 0;
+    static constexpr difference_type end_value = begin_value + 1;
+
+    /// iterator as signed integer type
+    difference_type m_it = std::numeric_limits<std::ptrdiff_t>::denorm_min();
+};
 } // namespace detail
 
 /// namespace to hold default `to_json` / `from_json` functions
@@ -4047,6 +4193,8 @@ class basic_json
     using lexer = ::nlohmann::detail::lexer<basic_json>;
     using parser = ::nlohmann::detail::parser<basic_json>;
 
+    using primitive_iterator_t = ::nlohmann::detail::primitive_iterator_t;
+
   public:
     using value_t = detail::value_t;
     // forward declarations
@@ -10405,144 +10553,6 @@ class basic_json
 
 
   private:
-    ///////////////
-    // iterators //
-    ///////////////
-
-    /*!
-    @brief an iterator for primitive JSON types
-
-    This class models an iterator for primitive JSON types (boolean, number,
-    string). It's only purpose is to allow the iterator/const_iterator classes
-    to "iterate" over primitive values. Internally, the iterator is modeled by
-    a `difference_type` variable. Value begin_value (`0`) models the begin,
-    end_value (`1`) models past the end.
-    */
-    class primitive_iterator_t
-    {
-      public:
-
-        difference_type get_value() const noexcept
-        {
-            return m_it;
-        }
-        /// set iterator to a defined beginning
-        void set_begin() noexcept
-        {
-            m_it = begin_value;
-        }
-
-        /// set iterator to a defined past the end
-        void set_end() noexcept
-        {
-            m_it = end_value;
-        }
-
-        /// return whether the iterator can be dereferenced
-        constexpr bool is_begin() const noexcept
-        {
-            return (m_it == begin_value);
-        }
-
-        /// return whether the iterator is at end
-        constexpr bool is_end() const noexcept
-        {
-            return (m_it == end_value);
-        }
-
-        friend constexpr bool operator==(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it == rhs.m_it;
-        }
-
-        friend constexpr bool operator!=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return !(lhs == rhs);
-        }
-
-        friend constexpr bool operator<(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it < rhs.m_it;
-        }
-
-        friend constexpr bool operator<=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it <= rhs.m_it;
-        }
-
-        friend constexpr bool operator>(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it > rhs.m_it;
-        }
-
-        friend constexpr bool operator>=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it >= rhs.m_it;
-        }
-
-        primitive_iterator_t operator+(difference_type i)
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
-
-        friend constexpr difference_type operator-(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it - rhs.m_it;
-        }
-
-        friend std::ostream& operator<<(std::ostream& os, primitive_iterator_t it)
-        {
-            return os << it.m_it;
-        }
-
-        primitive_iterator_t& operator++()
-        {
-            ++m_it;
-            return *this;
-        }
-
-        primitive_iterator_t operator++(int)
-        {
-            auto result = *this;
-            m_it++;
-            return result;
-        }
-
-        primitive_iterator_t& operator--()
-        {
-            --m_it;
-            return *this;
-        }
-
-        primitive_iterator_t operator--(int)
-        {
-            auto result = *this;
-            m_it--;
-            return result;
-        }
-
-        primitive_iterator_t& operator+=(difference_type n)
-        {
-            m_it += n;
-            return *this;
-        }
-
-        primitive_iterator_t& operator-=(difference_type n)
-        {
-            m_it -= n;
-            return *this;
-        }
-
-      private:
-        static constexpr difference_type begin_value = 0;
-        static constexpr difference_type end_value = begin_value + 1;
-
-        /// iterator as signed integer type
-        difference_type m_it = std::numeric_limits<std::ptrdiff_t>::denorm_min();
-    };
-
     /*!
     @brief an iterator value