To extend your point, this was written in the context of Scheme, which like most Lisps, is not statically typed. In Lisps, it's trivial to build up an object w

To extend your point, this was written in the context of Scheme, which like most Lisps, is not statically typed. In Lisps, it's trivial to build up an object with closures. (Create a fn that accepts some data, then return a data structure with fns that close over that data, and voila, object.) Building an OOP system is Lisp is a homework exercise.