How to give user free rein to edit a buffer in the middle of lisp code?

Question

I'm trying to run some code, a little like this:

(defun myfun ()
  (message "one")
  (user-does-things)
  (message "two")

I would like the code to do this:

1. display "one"
2. let the user edit in another buffer
3. When the user is done editing, display "two"

All my attempts so far have just displayed "one" and "two", leaving the user to do his editing after the code has finished running.

I'm also OK with a more disconnected approach, such as "I launch a buffer with a custom keymap so the user is able to do whatever they want in emacs until they hit a keybinding which calls back to my custom code" - I could use some help to do this as well though :D

Answer 1

The question is not too clear. But I think maybe what you're saying is that you want to:

1. Show message one.
2. Let the user start doing some arbitrary editing, in any buffer. No limits on what she can do.
3. Let the user indicate when she's done.
4. Show message two.

If that, or similar, is the case, then one way to realizes steps 2 and 3 is to use a recursive edit.

A recursive edit can be initiated by program or interactively -- in either case using function/command recursive-edit.

And a user can exit the current recursive edit using C-M-c (command exit-recursive-edit). You can exit all levels of recursive editing, returning to the top-level of Emacs, using C-] (command abort-recursive-edit).

For a start, you could do this, for example:

(defun myfun ()
  (message "one")
  (save-excursion (recursive-edit)) ; User does things
  (message "two"))

---

Library rec-edit.el (code) can help with recursive editing.

• It gives you a single key (C-M-c) to both enter and exit a recursive edit.
• It optionally highlights the mode-line indication, [...], to make clear that you are in a recursive edit, and what the recursion level is.