A Note On X Where X = "adding jump state to command."

“Adding jump state to command.” implies that position ((point)) that the added command is evaluated is added to jump state. In the other word, you can get back to (point) that you executed the command by using (better-jumper-jump-forward).

I was trying to add “jump state” to (+spell/previous-error) and +spell/next-error.

Note that +spell prefix means this command is provided by a Doom’s module. From a quick glance into the code, it is clear that — just like other Doom’s module — it implements branching condition to allow fallback behavior based on context such as current mode or available packages.

As of <2022-11-22 Tue>, I understand that better jumper is an Emacs’s package whose job is to provide “jumping back and forward functionality”. Vanilla Emacs has its own implementation, but, in my opinion, vim’s implementation is better – it is provided by evil-mode.

Trying to add “evil’s jump state to command” in Doom Emacs is confusing to me because better-jumper doesn’t provide function that allow command to remember where it “jumped” from – lets call this behavior “adding jump state to command.” Still, I found that I can simulate this behavior by evaluating <2258328192>.

(progn
  (better-jumper--push)
  (+spell/previous-error))

This finding was a deadline. I expected it because it was expecting such obvious usage to be provided by the package itself. I was right. Since I use evil-mode, the package that provides this support function is evil-mode. This fact was not clear until after I found the solution.

I wasn’t familiar with macro and structure in Elisp, so I didn’t know what information to focus on when reading code in evil package. By searching for keys words like jump and tinkering with functions that have “jump state”. I was able to figure out that “jump state” is provided by keyword :jump t. Copied and Pasted code from functions with desired behavior, I added :jump t to (evil-next-flyspell-error), see <2519460702>. Still, this didn’t work. I stuck again.

(evil-define-motion evil-next-flyspell-error (count)
  "Go to the COUNT'th spelling mistake after point."
  :jump t
  (interactive "p")
  (dotimes (_ count)
    (evil--next-flyspell-error t)))

Now, since I learned about keywords and have a metal framework of how evil-mode works, I was able to find this Reddit’s thread titled “evil-mode - jump back to last position.", and found the correct answer by RuleAndLine. He commented that

Like others are saying, you want C-o. For commands that don’t set a jump by default, you want to add something like this to your init file:

(evil-add-command-properties #‘foo :jump t)

Edit: this works for any emacs command, not just the ones defined by evil. So, like, I use (evil-add-command-properties #‘org-goto :jump t) so I can go to a random org heading then jump back to where I was before.

Hence, the correct answer is

(evil-add-command-properties #'+spell/next-error :jump t)
(evil-add-command-properties #'+spell/previous-error :jump t)

As of <2022-11-22 Tue>, I still don’t know how evil use properties to selectively produce behavior based on keyword, but, at this point, this seems like a trivial work, so I omitted it here.

That’s it.

Peace.

~milfex-lostex

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