deploy: 40a62947d3

api/basic_json/json_base_class_t.md

@@ -46,13 +46,93 @@ same name. Hidden members remain accessible via [`as_base_class`](as_base_class.
     The following code shows how to inject custom data and methods for each node.
      
     ```cpp
-    --8<-- "examples/json_base_class_t.cpp"
+    #include <iostream>
+    #include <nlohmann/json.hpp>
+    
+    class visitor_adaptor_with_metadata
+    {
+      public:
+        template <class Fnc>
+        void visit(const Fnc& fnc) const;
+    
+        int metadata = 42;
+      private:
+        template <class Ptr, class Fnc>
+        void do_visit(const Ptr& ptr, const Fnc& fnc) const;
+    };
+    
+    using json = nlohmann::json::with_base_class_t<visitor_adaptor_with_metadata>;
+    
+    template <class Fnc>
+    void visitor_adaptor_with_metadata::visit(const Fnc& fnc) const
+    {
+        do_visit(json::json_pointer{}, fnc);
+    }
+    
+    template <class Ptr, class Fnc>
+    void visitor_adaptor_with_metadata::do_visit(const Ptr& ptr, const Fnc& fnc) const
+    {
+        using value_t = nlohmann::detail::value_t;
+        const json& j = *static_cast<const json*>(this);
+        switch (j.type())
+        {
+            case value_t::object:
+                fnc(ptr, j);
+                for (const auto& entry : j.items())
+                {
+                    entry.value().do_visit(ptr / entry.key(), fnc);
+                }
+                break;
+            case value_t::array:
+                fnc(ptr, j);
+                for (std::size_t i = 0; i < j.size(); ++i)
+                {
+                    j.at(i).do_visit(ptr / std::to_string(i), fnc);
+                }
+                break;
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+                fnc(ptr, j);
+                break;
+            case value_t::discarded:
+            default:
+                break;
+        }
+    }
+    
+    int main()
+    {
+        // create a json object
+        json j;
+        j["null"];
+        j["object"]["uint"] = 1U;
+        j["object"].metadata = 21;
+    
+        // visit and output
+        j.visit(
+             [&](const json::json_pointer & p,
+                 const json & j)
+        {
+            std::cout << (p.empty() ? std::string{"/"} : p.to_string())
+                      << " - metadata = " << j.metadata << " -> " << j.dump() << '\n';
+        });
+    }
+    
     ```
     
     Output:
     
     ```json
-    --8<-- "examples/json_base_class_t.output"
+    / - metadata = 42 -> {"null":null,"object":{"uint":1}}
+    /null - metadata = 42 -> null
+    /object - metadata = 21 -> {"uint":1}
+    /object/uint - metadata = 42 -> 1
+    
     ```
 
 ## See also
@@ -62,5 +142,5 @@ same name. Hidden members remain accessible via [`as_base_class`](as_base_class.
 
 ## Version history
 
-- Added in version 3.12.0.
+- Added in version 3.11.3.
 - Made a public member type in version 3.13.0; it was private before, so it could not be named outside the class.