Agreed, but I think the distinction is that the original book was talking about language design. Since languages are Turing complete we can always implement the

Agreed, but I think the distinction is that the original book was talking about language design. Since languages are Turing complete we can always implement the features of one in another, but it stands that open recursion is not a feature of his Dart subset. It would certainly be a stretch to call a language OO just because you can replicate OO features from first principles!