Add type & value fields to primitive json types

This aligns with how custom types are exported to JSON.

Author: dyackzan

src/json_export.cpp

@@ -14,21 +14,28 @@ bool JsonExporter::toJson(const Any& any, nlohmann::json& dst) const
   nlohmann::json json;
   auto const& type = any.castedType();
 
+  const std::string type_field = "__type";
+  const std::string value_field = "value";
+
   if(any.isString())
   {
-    dst = any.cast<std::string>();
+    dst[type_field] = "string";
+    dst[value_field] = any.cast<std::string>();
   }
   else if(type == typeid(int64_t))
   {
-    dst = any.cast<int64_t>();
+    dst[type_field] = "int64_t";
+    dst[value_field] = any.cast<int64_t>();
   }
   else if(type == typeid(uint64_t))
   {
-    dst = any.cast<uint64_t>();
+    dst[type_field] = "uint64_t";
+    dst[value_field] = any.cast<uint64_t>();
   }
   else if(type == typeid(double))
   {
-    dst = any.cast<double>();
+    dst[type_field] = "double";
+    dst[value_field] = any.cast<double>();
   }
   else
   {