implemented lazy loading for object_ptr and belongs_to

source/core/utils/value.cpp

@@ -39,6 +39,14 @@ value &value::operator=(value &&x) noexcept {
   return *this;
 }
 
+bool value::operator==(const value &rhs) const {
+  return type_ == rhs.type_ && value_ == rhs.value_;
+}
+
+bool value::operator!=(const value &rhs) const {
+  return !operator==(rhs);
+}
+
 std::string value::str() const {
   return as<std::string>().value_or("");
 }