The Kitchin Research Group

There are times where I want an org-file to be partly read-only. For example, there might be instructions that should not be modified. In this post we consider how to implement that. For now, we only want an org-section to be read-only, and we will designate those sections by a tag read_only. Then, the idea is that a hook function would be run when the org-file is loaded, and mark regions of text as read-only before the user can do anything.

In Emacs, you can mark a section of text, and set it to have a property of read-only. So, we can just map over the entries, and any heading that is tagged as read_only can be made read-only!

Here we set the first few characters of this buffer to be read-only.

(add-text-properties 1 8 '(read-only t))

t

Emacs is semi-serious about what read-only means. You cannot even change properties of read-only text, unless you set inhibit-read-only as a variable.

(let ((inhibit-read-only t))
 (remove-text-properties 1 8 '(read-only t)))

t

Now, we can map over the entries in this buffer, and set any heading tagged read_only to actually be that way like this.

(org-map-entries (lambda ()
                   (let* ((element (org-element-at-point))
                          (begin (org-element-property :begin element))
                          (end (org-element-property :end element)))
                     (add-text-properties begin end '(read-only t))))
                 "read_only")

To get this to work when org-mode is turned on, we just wrap it in a function, add the function to a hook, and a function to undo the read-only behavior. I found that if I use the end reported by org-element-at-point, it includes the first character of the next section, we take one away from the end to avoid that.

(defun org-mark-readonly ()
  (interactive)
  (org-map-entries
   (lambda ()
     (let* ((element (org-element-at-point))
            (begin (org-element-property :begin element))
            (end (org-element-property :end element)))
       (add-text-properties begin (- end 1) '(read-only t))))
   "read_only")
 (message "Made readonly!"))


(defun org-remove-readonly ()
  (interactive)
  (org-map-entries
   (lambda ()
     (let* ((element (org-element-at-point))
            (begin (org-element-property :begin element))
            (end (org-element-property :end element))
            (inhibit-read-only t))
         (remove-text-properties begin (- end 1) '(read-only t))))
     "read_only"))

(add-hook 'org-mode-hook 'org-mark-readonly)

That seem to be all there is. After executing the code above, when I open this file, the next section is read-only! I can use the other function to remove that if I need to edit it. Score one for Emacs + org-mode!

Copyright (C) 2014 by John Kitchin. See the License for information about copying.

org-mode source

Org-mode version = 8.2.7c