I have semi-frequent occasion to work in Clojure, but Clojure lacks some features of Common Lisp that I consider important. The most important of these is that Common Lisp, like Smalltalk, but unlike most other languages, including Clojure, is designed from the ground up to support developing a program interactively while it runs. I want to see if I can have Clojure for those cases where it's the right tool, without losing the programming-as-teaching features of Common Lisp that I miss when working in other languages.
I know someone is probably going to object that Clojure, too, is designed to support interactive development; my answer is: no, it isn't. Not in the sense I'm talking about.
As an example of what I mean, consider the standard Common Lisp generic function UPDATE-INSTANCE-FOR-REDEFINED-CLASS. This function is part of a standard protocol in Common Lisp that enables your program to automatically update existing instances of previously-defined classes to properly confor