How can I edit read-only text after pasting?

Question

I want to create a buffer where some parts are editable, but others are not. I'm using the read-only string property to do this, e.g.:

(with-current-buffer (get-buffer-create "*scratch-demo*")
  (insert ";; you can edit me\n")
  (insert (propertize
           ";; but you cannot edit me\n"
           'read-only t)))

If I paste the second line into a buffer in fundamental mode, I can edit it.

this buffer is in fundamental mode
;; but you cannot *foo* edit me

However, if I paste the second line into an emacs-lisp-mode buffer, I cannot edit it.

;; this buffer is in emacs-lisp-mode
;; I cannot modify the line below:
;; but you cannot edit me

How can I ensure users can edit text, which has been yanked from read-only portions of my buffer?

Answer 1

1. I don't see the problem you mention. Maybe I miss the recipe. I did this, in a session from emacs -Q:

   a. In buffer *scratch* I typed your code and evaluated it.

   b. I visited buffer *scratch-demo*. The text of the second line was read-only (could not modify it). I copied the text there using M-w.

   c. I visited a buffer in Emacs Lisp mode and yanked the copied text, using C-y. I had no problem modifying the yanked text, including the part from the read-only portion.

   d. I did the same thing in a buffer in Fundamental mode - same effect.

2. If you have trouble with this kind of thing, have a look at function insert-for-yank and variables yank-handled-properties and yank-excluded-properties, to get the properties you want and not get the properties you do not want, respectively.

   See also functions remove-yank-excluded-properties and insert-buffer-substring-as-yank.

   See the Elisp manual, node Yanking for details.