Re: hook for buffers becoming writable/read-only

[Stefan Monnier <monnier@iro.umontreal.ca>]

> I have a minor mode that wishes to disable itself when the buffer becomes
> writable, but I do not see a way to do it.

Indeed, there is no such hook.  I can think of two ways to get something
similar:
- use the usual post-command-hook to check the state of the
  variable and react accordingly.
- if your minor mode is mostly a bunch of key-bindings, you can do what
  I did in diff-mode and use buffer-read-only as the minor-mode
  variable:

  [...]
  ;; Neat trick from Dave Love to add more bindings in read-only mode:
  (lexical-let ((ro-bind (cons 'buffer-read-only diff-mode-shared-map)))
    (add-to-list 'minor-mode-overriding-map-alist ro-bind)
    ;; Turn off this little trick in case the buffer is put in view-mode.
    (add-hook 'view-mode-hook
	      (lambda ()
		(setq minor-mode-overriding-map-alist
		      (delq ro-bind minor-mode-overriding-map-alist)))
	      nil t))
  [...]


-- Stefan