Well, it could be done in JS or Lisp. You'd have to replace all the references to dependencies in every function with a hash of the implementation of the refere

Well, it could be done in JS or Lisp. You'd have to replace all the references to dependencies in every function with a hash of the implementation of the referenced function and use some kind of global lookup table (which would need to be a distributed hash table or something). But this would be slow, so you'd need a compiler or some kind of processor to inline stuff and do CPS transforms, and by that time you've basically implemented a janky version of Unison.