> Mixins are a useful mental model for some kinds of code reuse though.
They are, but I can think of at least one core feature-based solution to do the same thing with less overhead. Each mix-in or trait could easily be in its own table, to be joined with the object as it's being constructed in whatever fashion desirable.
(I don't like his class style either, the constructor should return self, and I just like prototypal inheritance anyway).