making specific regions of a buffer read-only

Question

I know it's possible to make a "portion" of a buffer read-only. As an effect, the whole line becomes uneditable. What I would like it to make a specific region uneditable, for exemple a rectangle region :

- item n°1 (uneditable) : "editable part 1"
- item n°2 (uneditable) : "editable part 2"
- and so on.

I'm pretty sure it's something customizable but I'm not well acquainted with elisp yet. Thanks for your insights.

Answer 1

It sounds like you very specifically want this for rectangles, rather than for "specific regions".

You can combine https://emacs.stackexchange.com/a/10093/454 (which works on a region) with these rectangle commands:

(defun set-rectangle-read-only (begin end)
  "`set-region-read-only' on a rectangle."
  (interactive "r")
  (save-excursion
    (apply-on-rectangle
     (lambda (startcol endcol)
       (set-region-read-only
        (progn (move-to-column startcol) (point))
        (progn (move-to-column endcol) (point))))
     begin end)))

(defun set-rectangle-writeable (begin end)
  "`set-region-writeable' on a rectangle."
  (interactive "r")
  (save-excursion
    (apply-on-rectangle
     (lambda (startcol endcol)
       (set-region-writeable
        (progn (move-to-column startcol) (point))
        (progn (move-to-column endcol) (point))))
     begin end)))