deploy: 40a62947d3

api/adl_serializer/from_json.md

@@ -41,13 +41,51 @@ class (either explicitly or via the conversion operators).
     called by the `adl_serializer` when `get<ns::person>()` is called.
         
     ```cpp
-    --8<-- "examples/from_json__default_constructible.cpp"
+    #include <iostream>
+    #include <nlohmann/json.hpp>
+    
+    using json = nlohmann::json;
+    
+    namespace ns
+    {
+    // a simple struct to model a person
+    struct person
+    {
+        std::string name;
+        std::string address;
+        int age;
+    };
+    } // namespace ns
+    
+    namespace ns
+    {
+    void from_json(const json& j, person& p)
+    {
+        j.at("name").get_to(p.name);
+        j.at("address").get_to(p.address);
+        j.at("age").get_to(p.age);
+    }
+    } // namespace ns
+    
+    int main()
+    {
+        json j;
+        j["name"] = "Ned Flanders";
+        j["address"] = "744 Evergreen Terrace";
+        j["age"] = 60;
+    
+        auto p = j.get<ns::person>();
+    
+        std::cout << p.name << " (" << p.age << ") lives in " << p.address << std::endl;
+    }
+    
     ```
     
     Output:
     
     ```json
-    --8<-- "examples/from_json__default_constructible.output"
+    Ned Flanders (60) lives in 744 Evergreen Terrace
+    
     ```
 
 ??? example "Example: (2) Non-default-constructible type"
@@ -56,13 +94,67 @@ class (either explicitly or via the conversion operators).
     realize the conversion of a non-default-constructible type.
         
     ```cpp
-    --8<-- "examples/from_json__non_default_constructible.cpp"
+    #include <iostream>
+    #include <nlohmann/json.hpp>
+    
+    using json = nlohmann::json;
+    
+    namespace ns
+    {
+    // a simple struct to model a person (not default constructible)
+    struct person
+    {
+        person(std::string n, std::string a, int aa)
+            : name(std::move(n)), address(std::move(a)), age(aa)
+        {}
+    
+        std::string name;
+        std::string address;
+        int age;
+    };
+    } // namespace ns
+    
+    namespace nlohmann
+    {
+    template <>
+    struct adl_serializer<ns::person>
+    {
+        static ns::person from_json(const json& j)
+        {
+            return {j.at("name"), j.at("address"), j.at("age")};
+        }
+    
+        // Here's the catch! You must provide a to_json method! Otherwise, you
+        // will not be able to convert person to json, since you fully
+        // specialized adl_serializer on that type
+        static void to_json(json& j, ns::person p)
+        {
+            j["name"] = p.name;
+            j["address"] = p.address;
+            j["age"] = p.age;
+        }
+    };
+    } // namespace nlohmann
+    
+    int main()
+    {
+        json j;
+        j["name"] = "Ned Flanders";
+        j["address"] = "744 Evergreen Terrace";
+        j["age"] = 60;
+    
+        auto p = j.get<ns::person>();
+    
+        std::cout << p.name << " (" << p.age << ") lives in " << p.address << std::endl;
+    }
+    
     ```
     
     Output:
     
     ```json
-    --8<-- "examples/from_json__non_default_constructible.output"
+    Ned Flanders (60) lives in 744 Evergreen Terrace
+    
     ```
 
 ## See also