Making highlight-sexp follow modus-themes-toggle

Posted: Jan 26, 2023 - Modified: Jun 18, 2026| elisp, emacs

[2026-06-18 Thu]: I think I'll stop using highlight-sexp for now. It's a little finicky when I change themes.
[2023-01-27 Fri] Prot just added a modus-themes-get-color-value

function. Yay! Also, it turns out that I need to update the overlay in all the buffers.

I'm experimenting with using the highlight-sexp minor mode to highlight my current s-expression, since I sometimes get confused about what I'm modifying with smartparens. The highlight-sexp background colour is hardcoded in the variable hl-sexp-background-color, and will probably look terrible if you use a light background. I wanted it to adapt when I use modus-themes-toggle. Here's how that works:

(defun sacha-hl-sexp-update-overlay ()
  (when (overlayp hl-sexp-overlay)
    (overlay-put
     hl-sexp-overlay
     'face
     `(:background
       ,(modus-themes-get-color-value 'bg-inactive)))))
(defun sacha-hl-sexp-update-all-overlays (&rest args)
  (interactive)
  (dolist (buf (buffer-list))
    (with-current-buffer buf
      (when highlight-sexp-mode
        (sacha-hl-sexp-update-overlay)))))

  (use-package highlight-sexp
    :vc (:url "https://github.com/daimrod/highlight-sexp")
    :after modus-themes
    :hook
    ((emacs-lisp-mode . highlight-sexp-mode)
     (modus-themes-after-load-theme . sacha-hl-sexp-update-all-overlays))
    :config
    (advice-add 'hl-sexp-create-overlay :after 'sacha-hl-sexp-update-overlay))