Actually there was a lot of thought given to flexibility, I think a lot of the concepts were not exposed well due to the large project scope. Maru (which is the

Actually there was a lot of thought given to flexibility, I think a lot of the concepts were not exposed well due to the large project scope. Maru (which is the underlying STEPS runtime) for instance was designed to be completely replaceable (See COLA papers) using a composition mechanism similar to fexprs. Maru is also very easily bootstrapped as the VM/runtime and compiler come in at under 2KLOC with all the facilities.