mode-line, Status :: Added to Agenda

Question

I'd like some kind of visual feedback in the mode-line, saying whether the current buffer is a file that is added to the org-agenda. Is there some way to do that?;)

Answer 1

I recommend always avoiding unnecessary dynamic evaluations in the mode line, so I suggest you do the look-up in find-file-hook. The simplest approach to that means that you won't automatically see mode line 'corrections' to existing buffers if you update org-agenda-files (you would need to revisit the file), but the benefit is that the mode line rendering is very cheap.

(require 'org)

(defvar-local my-org-agenda-file-p nil
  "Whether this buffer's file is a member of `org-agenda-files'.")

(defun my-org-agenda-file-check ()
  "Update `my-org-agenda-file-p'."
  (when (member buffer-file-name (org-agenda-files t))
    (setq my-org-agenda-file-p t)))

(add-hook 'find-file-hook #'my-org-agenda-file-check)

(add-to-list 'global-mode-string '(my-org-agenda-file-p "Agenda"))

I can't guess whether you want to pass the ARCHIVES argument to org-agenda-files, so you should check that yourself.

(org-agenda-files &optional UNRESTRICTED ARCHIVES)