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Interesting bits of life

Org mode links for Emacs Slack

Too long; didn't read

I shared how to have slack messages pop up in your Org agenda, here I show how to just click on your messages to go back to the channel with Org Links. You can find the code on: https://github.com/ag91/ol-emacs-slack.

The problem

I recently shared how to integrate Emacs Slack with the Org Agenda (I also added it to Worg, and by the way it generated an interesting discussion on an issue of Emacs Slack). A bothering thing in my workflow was to find the conversation present in my agenda. A few times I ended up in the wrong group channel, and it really felt that something was missing.

It is a problem indeed

The funny thing is that other people would like to have this feature: https://github.com/yuya373/emacs-slack/issues/475. How good is to feel I am not the only one?!

And there is a solution

That is what brought me to implement my first custom Org Link! Kudos to Org developers: it is easy-peasy :D

The Org Link interface is elegant:

(org-link-set-parameters "emacs-slack"
                         :follow #'ol/slack-follow-link
                         :export #'ol/slack-export
                         :store #'ol/slack-store-link)

We need a way to follow a link, to export it to another format and to store it. So far easy!

Let's get to the Emacs Slack side of things: easiest to hardest.


Banal copy paste from the Org Link example:

(defun ol/slack-export (link description format)
  "Export a emacs-slack link from Org files."
  (let ((desc (or description link)))


You need to know that the Emacs Slack code is Common Lisp flavoured Elisp AND Object Oriented! This was my first experience with the object system of Common Lisp: cooooooool (and a slightly painful for a functional programmer)!!!

(defun ol/slack-store-link ()
  "Store a link to a man page."
  (when (eq major-mode 'slack-message-buffer-mode)
    (let* ((buf slack-current-buffer)
           (team (slack-buffer-team buf))
           (team-name (oref team name))
           (room (slack-buffer-room buf))
           (room-name (slack-room-name room team))
           (link (funcall
                  (cl-typep buf 'slack-thread-message-buffer)))
           (description ))
       :type "emacs-slack"
       :link (concat "emacs-slack:" link)
       :description (concat "Slack message in #" room-name)

You see oref there? Object orientation in action: that is a property getter :) Even the slack buffer is an object. Very-super-cool!


Here there are dragons! Fundamentally this is the function I came up with:

(defun ol/slack-follow-link (link)
  "Follow LINK with format `   team - channel'."
  (let* ((team (--> link
                    (s-split "-" it)
         (team-object (ol/slack-string-to-team team)))
    (slack-room-display (ol/slack-string-to-room team-object link) team-object)))

I really needed a function that takes the name of a room and the name of a team and opens the room for me. That is missing in the code base, and my unfamiliarity with Common Lisp syntax slowed down my progress (it is a couple of weeks I am crunching the code). Funny thing? I also needed to unfold a macro:

(defun ol/slack-room-select (room rooms team)
  "Select ROOM from ROOMS and TEAM."
  (let* ((alist (slack-room-names
                 rooms team #'(lambda (rs) (cl-remove-if #'slack-room-hidden-p rs))))
         (selected (cdr (cl-assoc room alist :test 'ol/room-name-equal))))

In the original code the above is in a macro, but I really needed a sane way of comparing the room name with the input string: ol/room-name-equal.

My code is insane though (I will refactor if anybody asks me!):

(defun ol/room-name-equal (room channel-room)
  "Check ROOM is equal to CHANNEL-ROOM."
   (s-downcase (s-trim room))
    (let ((trimmed (s-trim (s-chop-prefix " * " channel-room))))
      (if (> (length trimmed) (length room))
          (substring trimmed 0 (length room))

It seems that random spaces and characters appear in front and at the end of room names and I dealt with it by trial and error: so please report issues if for some reason does not work for you.

Also worth to know that there are 3 kinds of rooms: ims, groups and channel. I found way of distinguish them, but also open an issue on the repository if you find errors.


What a lovely deep dive in the code of Emacs Slack. Object orientation in Lisp: the language is just majestic and paradigm-inclusive. Please smile at my amusement when you store your first Emacs Slack link!

Happy Hacking!