Org-roam selective link insertion

This article does not cover how to use org-roam. It is simply a step by step analysis of a potentially sketchy solution to overcome a niche problem.

If anyone wants to write their own org-roam configuration, I would suggest that they visit Jethro’s dotfiles.

While most mortals are still learning how to use it efficiently, occasionally falling in the trap of overthinking stuff, while trying to practice Zettelkasten as a means to get better in our pursuits, he seems to have all this figured out. After all he is the creator of the package.

If there is something I always wanted to tackle in org-roam, is that I quite often, when revisiting older nodes, encounter phrases and/or topics I have built on since then. Manually fixing these missing links has been quite a burden.

That functionality, was not very difficult to achieve.

The solution consists of two parts:

• The function that does everything
• The keybinding to use :P

Focusing on the hard stuff first: the function. Since I am an evil user, I use visual mode quite a lot, and it feels like the perfect tool for this job. Whenever I find a snippet I want to replace with a link to the related node, I can easily press v, select the appropriate text and then call the function.

Upon selection of text in emacs the text’s starting and ending points are marked with (region-beginning) and (region-end), respectively. Knowing just those two we can easily select the desired string:

(buffer-substring-no-properties (region-beginning) (region-end))

Normally, that would be all, but to make my life a little bit easier, due to my bad (?) habit of using solely the w and not the e motion, I wanted to automatically strip the selected string of any undesired whitespace. This step improves the accuracy of the subsequent processing

(string-trim-whitespace (buffer-substring-no-properties (region-beginning) (region-end)))

Having the selected text in the proper form, we then want to search our org-roam database for the proper node. If such a node exists, we want to get it’s id so that we can then insert the link in our starting file.

(progn
  ;; Open a node-find prompt with the selected-text as initial input
  ;; If a node is found/created open it on a different window
  (org-roam-node-find t selected-text)
  ;; If the previous part runs as it is supposed
  ;; get the id of the file we want to link to
  (org-roam-node-id (org-roam-node-at-point)))

We’re getting there. So far, we have both selected the text, properly formatted it, and then found/created the node we want the text to point to. The only thing left here is to replace the plain text with a link to our target node.

(with-current-buffer current-buffer
            (progn
              (goto-char re-start)
              (delete-region re-start (search-forward selected-text))
              (insert (concat "\[\[ID:" id "\]\[" selected-text "\]\]"))
              (evil-force-normal-state)
              ))

Now, let’s put it all together.

(defun my-org-roam-node-find-selected-text ()
  "Open org-roam-node-find with selected text as initial input
and replace with org-roam link if node is selected or created."
  (interactive)
    (let* ((re-start (region-beginning))
           (selected-text (string-trim-whitespace (buffer-substring-no-properties re-start (region-end))))
           (current-buffer (current-buffer))
           (id (progn
                 (org-roam-node-find t selected-text)
                 (org-roam-node-id (org-roam-node-at-point)))))
      (if  (not (eq current-buffer (current-buffer)))
          (with-current-buffer current-buffer
            (progn
              (goto-char re-start)
              (delete-region re-start (search-forward selected-text))
              (insert (concat "\[\[ID:" id "\]\[" selected-text "\]\]"))
              (evil-force-normal-state)
              ))
      )
    )
  )

Now as far as the keybinding itself is concerned, there is no reason to analyze it. R (for Roam) in visual mode points to a command I do not remember myself ever using (and frankly, of little use I suppose), so I can safely change it to something much more helpful.

(define-key evil-visual-state-map (kbd "R") 'my-org-roam-node-find-selected-text)