Deduce class-type based on first member mapping

code/json/marshaling.hxx

@@ -140,24 +140,42 @@ namespace code::json
 
   };
 
-  template<typename T, typename... Members>
+  template<typename First, typename... Members>
   struct mapping_t
   {
+    using T = First::T;
+
+    static
+    void
+    do_marshal(variant& v, T const& instance, marshaling_context_t* context)
+    {
+      First::marshal(v, instance, context);
+      ((Members::marshal(v, instance, context)), ...);
+    }
+
     static
     variant
     marshal(T const& instance, marshaling_context_t* context)
     {
       variant v{std::map<std::string, variant>{}};
-      ((Members::marshal(v, instance, context)), ...);
+      do_marshal(v, instance, context);
       return v;
     }
 
+    static
+    void
+    do_unmarshal(T& instance, variant const& v, marshaling_context_t* context)
+    {
+      First::unmarshal(instance, v, context);
+      ((Members::unmarshal(instance, v, context)), ...);
+    }
+
     static
     T
     unmarshal(variant const& v, marshaling_context_t* context)
     {
       T instance;
-      ((Members::unmarshal(instance, v, context)), ...);
+      do_unmarshal(instance, v, context);
       return instance;
     }
 

code/json/marshaling.test.cxx

@@ -26,7 +26,6 @@ struct name_t
   std::string last;
 
   using json = mapping_t<
-    name_t,
     member_t<"/person/first", &name_t::first>::pointer_t,
     member_t<"/person/last", &name_t::last>::pointer_t
   >;

code/json/serialize.test.cxx

@@ -18,7 +18,6 @@ struct person_name {
   std::string last;
 
   using json = mapping_t<
-    person_name,
     member_t<"first", &person_name::first>,
     member_t<"last", &person_name::last>
   >;
@@ -30,7 +29,6 @@ struct person {
   int age;
 
   using json = mapping_t<
-    person,
     member_t<"name", &person::name>,
     member_t<"age", &person::age>
   >;