Earlier quoted context omitted.
Not the OP but would somebody be able to summarize HOW are the lisp REPLs different then to me? I've written limited amount of clojure and common lisp just to play around and I don't recall any difference between Clojure REPL and the REPL I get for say Kotlin inside IntelliJ idea. Maybe the ability to send expression from the IDE into the REPL with one keybind but I cannot say it's not possible with the Kotlin one ri…
There's a person above saying that it's about being to able to mutate program state from the repl, which is a thing that's also possible in any repl for a language with managed memory.
There are some other affordances for interactive programming, such as a standard way to update existing instances of classes. I’m sure you could implement this sort of functionality in any language, but this is universal and comes for free in Common Lisp.
CL also has other interesting features such as macros, multiple dispatch, compilation at runtime, and being able to save a memory snapshot of the program. It’s quite unique.