[the_af]

> The author may have assumptions I'm missing here but the standard way to have a "one of these or one of these" thing is to have two classes inherent from a given abstract base class and use a pointer to the base class.

I think this is what the author describes in the sentence that follows the one you quoted. He also calls it "a common (ab)use of object oriented programming."

[AnimalMuppet]

So it's reasonable to define data types in this way in OCaml, but it's abusing OO to do so in C++? Given that classes are data types, that seems... less than consistent.