One could also argue that once you have Emacs set up, you have enough to learn Lisp. Use ielm mode as a REPL, or lisp-mode for longer code bits. Sure you don't

One could also argue that once you have Emacs set up, you have enough to learn Lisp. Use ielm mode as a REPL, or lisp-mode for longer code bits. Sure you don't get lexical scope standard, but more than enough to muck around... The elisp info page built in is a fine reference.