I have a use case for optional fields. I store a vector map. This map has a name, a few other fields, and list of polygons. The polygons are large. If I just want to rename the map, I want to be able to publish an update message that leaves the polygons unset. That would in turn be interpreted as "keep the current polygons I already know about" at the receiver. I don't want a separate update message for each map field. It seems that I would still need a separate message to update individual polygons, but I would still hope to leave fields that shouldn't change out of the message. JSON typically utilizes this principle: if a property is null for the serializer the property name isn't included and, vice-versa, when deserializing absent properties don't change the existing value in the target. --- [Visit Topic](https://discourse.ros.org/t/optional-fields-in-message/991/15) or reply to this email to respond. If you do not want to receive messages from ros-users please use the unsubscribe link below. If you use the one above, you will stop all of ros-users from receiving updates. ______________________________________________________________________________ ros-users mailing list ros-users@lists.ros.org http://lists.ros.org/mailman/listinfo/ros-users Unsubscribe: