Composition and inheritance: the Julian way

well, you know where all this discussion comes from :wink:. Extending the behavior of, say, a DataFrame object is not trivial at all…

It would be nice if you could provide an example which solves the Person/Citizen problem in the first post using traits. Please :pray: avoid encapsulation since on a real example (e.g. a DataFrame) this means re-defining hundreds of methods…