It's a pretty poor REPL. Every time you update your code, you have to reload, and you lose all your previous bindings. And, no, I don't simply want to rerun my interactive session. I want a persistent session.

When doing theorem proving in Ocaml (which was both ML's and Lisp's MOs), my REPL session could last months. I sadly didn't have Lisp's great (save-lisp-and-die) in Ocaml, but I was able to snapshot the process state to get semiway there.

Common Lisp is built around the idea that your runtime is a persistent live system that you stay in and modify and introspect. Your tool-chain should consist entirely of Lisp objects that are part of your runtime, and should themselves be modifiable. Everything is programmable. The Art of the Metaobject Protocol is still one of the coolest things I've ever read.

I'm a Haskeller now, through and through, but Haskell's REPL and runtime isn't comparable to Lisp's.

AFAIK Haskell doesn't support metaprogramming. Perhaps you mean "Template Haskell"?