I used to develop with Smalltalk which is totally interactive in the way that you can change code in any browser (including the debugger) and the change becomes immediately effective in the application (without restart or anything). My question is whether there any other languages that have this. I know of none except maybe Self, but Self is really dead I fear.

Java has hot code replacement which only works partially (as long as public methods don't change). JRebel makes it better. But I'm looking for a language that supports interactive development from the beginning like Smalltalk. Note, that I don't mean a REPL. A REPL is still separated from the application, so what is executed in the REPL is not immediately effective in the application as with an interactive programming language or development environment.