This is something I really like about Common Lisp, but after ~30 years of progress, I am a bit disappointed with improvements in the field of interactive develo

This is something I really like about Common Lisp, but after ~30 years of progress, I am a bit disappointed with improvements in the field of interactive development. The process you describe is possible in JavaScript and many other languages as well. Updating a JAR is trivial, but doing it in a running system is uncomfortable. The first thing to start with is versioning at the function, class, package, or module level. Combine that with versioning of data, and you've got my interest :)