this post was submitted on 28 Nov 2023
1 points (100.0% liked)

Emacs

310 readers
2 users here now

A community for the timeless and infinitely powerful editor. Want to see what Emacs is capable of?!

Get Emacs

Rules

  1. Posts should be emacs related
  2. Be kind please
  3. Yes, we already know: Google results for "emacs" and "vi" link to each other. We good.

Emacs Resources

Emacs Tutorials

Useful Emacs configuration files and distributions

Quick pain-saver tip

founded 1 year ago
MODERATORS
rglullis
raphael
1
It is recommended to not use lambdas in (add-hook) expressions. Is there a better way to do (setq)s for major modes without (add-hook) at all? (alien.top)
submitted 11 months ago by ragnese@alien.top to c/emacs
6 comments fedilink hide all child comments
 

For example, let's say I were to change backward-delete-char-untabify-method for prog-mode buffers. Naively, I'd write something like,

(add-hook 'prog-mode-hook (lambda ()
                       (setq-local backward-delete-char-untabify-method 'hungry)))

but the documentation recommends against using lambdas in add-hook calls (which makes sense). I can, of course, just make a named function instead of a lambda and pass that to add-hooks. But, rather than do that, is there any other option for setting variables automatically for modes besides a hook like this?

Also, as a bonus question, if I wanted to also do something like enable show-paren-mode for all prog-mode buffers, which of the following do you consider "better" (assume that this is not something that is likely to change frequently):

;; option 1
(defun my-prog-mode-settings ()
  (setq-local backward-delete-char-untabify-method 'hungry))

(add-hook 'prog-mode-hook #'my-prog-mode-settings)
(add-hook 'prog-mode-hook #'show-paren-mode)

;; option 2
(defun my-prog-mode-settings ()
  (setq-local backward-delete-char-untabify-method 'hungry)
  (show-paren-mode))

(add-hook 'prog-mode-hook #'my-prog-mode-settings)

Obviously, I realize that it's not really important, but I feel like bike-shedding this morning.

you are viewing a single comment's thread
view the rest of the comments
[–] JDRiverRun@alien.top 1 points 11 months ago

You can also use this approach:

(add-hook 'text-mode-hook
          (defalias 'my/fancy-mode-setup
            (let (some-closure-var)
              (lambda () ...))))

Advantage is that there can be only one alias, and it's added by name to the hook. So you can alter and re-run add-hook without duplication, and you can easily remove it by name. Best of all, you can create a closure (the let there) if you need that gives you "local storage in the function" that persists between runs (without cluttering the namespace with global variables).