Question

Can anyone suggest any pointers / tutorials or information on how to get an interactive command-line mode in emacs. I have looked at comint and shell modes but these talk to a sub-process. I just want an interactive command line that talks to an elisp function, not a sub-process like /bin/bash. The idea is to use it to interact with simple interpreters written in elisp (just for fun).

Answer 1

Try M-x ielm for inferior Emacs Lisp mode. You can get help by typing (describe-mode)RET at the prompt.

Strangely enough, it uses “a dummy process to keep comint happy” but the process isn’t actually used to process your commands. If you want to replace ielm-eval-input with your own function you could probably hack that.