Re: special-mode buffer changes to fundamental when modified

[Michael Heerdegen <michael_heerdegen@web.de>]

Stefan Huchler <stefan.huchler@mail.de> writes:

> condition-case: Buffer is read-only: #<killed buffer>

Well, your code behaved differently depending on whether the buffer
already existed or not.

> Can you post a exact source you used that did work? maybe my emacs
> setup is messed up somehow.

Ok, I used the excerpt you posted and edited it very slightly.  There
was indeed a problem: `special-mode', from which your mode derived,
makes the buffer read-only.  So I suggest to bind `inhibit-read-only' to
ignore the read-only flag, since I assume you want the buffer to stay
read-only.

This is the slightly edited example, that indeed works as expected (and
for every call the same):

#+begin_src emacs-lisp
(defvar kodi-remote-keyboard-mode-map
  (let ((map (make-sparse-keymap))
	;; (menu-map (make-sparse-keymap))
        )
    (define-key map (kbd "-") #'kodi-remote-volume-decrease)
    (define-key map (kbd "<tab>") #'kodi-remote-toggle-fullscreen)
    map)
  "Keymap for kodi-remote-keyboard-mode.")

(define-derived-mode kodi-remote-keyboard-mode special-mode "kodi-remote-keyboard"
  "Major mode for remote controlling kodi instance with keyboard commands
Key bindings:
\\{kodi-remote-keyboard-mode-map}")

(defun kodi-remote-keyboard ()
  "Open a `kodi-remote-keyboard-mode' buffer."
  (interactive)
  (let* ((name "*kodi-remote-keyboard*")
         (buffer (get-buffer-create name)))
    (unless (eq buffer (current-buffer))
      (with-current-buffer buffer
        (let ((inhibit-read-only t))
          (erase-buffer)
          (kodi-remote-keyboard-mode)
          (insert (concat "Kodi Remote:\n"
                          (substitute-command-keys
                           "\\{kodi-remote-keyboard-mode-map}"))))
        (switch-to-buffer-other-window buffer)))))
#+end_src


HTH,

Michael.