Add function to cycle through auto-hscroll-mode settings

And set it to current-line by default; when I only have the odd line
poking out of the window, I prefer not jerking the whole buffer
horizontally.

Should make C-c d h repeatable, someday.

1 files changed, 19 insertions, 0 deletions

diff --git a/.config/emacs/init.el b/.config/emacs/init.el
index 3fe49c6..1d3f1e7 100644
--- a/.config/emacs/init.el
+++ b/.config/emacs/init.el
@@ -158,6 +158,20 @@
                               left-margin)))
       (set-window-margins window left-margin right-margin))))
 
+(defun my/auto-hscroll-toggle ()
+  (interactive)
+  ;; Use indices to avoid confusing `if-let*' with nil.
+  (if-let* ((values '(nil t current-line))
+            (prev (seq-position values auto-hscroll-mode))
+            (next (% (1+ prev) (length values))))
+      (progn
+        (message (concat
+                  (propertize (format "%s" (nth prev values)) 'face 'shadow)
+                  " → "
+                  (propertize (format "%s" (nth next values)) 'face 'bold)))
+        (setopt auto-hscroll-mode (nth next values)))
+    (error "Unknown value for auto-hscroll-mode: %s" auto-hscroll-mode)))
+
 (defun my/kill (stuff)
   (kill-new stuff)
   (message "%s" stuff))
@@ -280,6 +294,7 @@ list and require no escaping."
 (my/define-prefix-command my/display-map
   "Keymap for display-related commands."
   '(("c" my/centered-mode)
+    ("h" my/auto-hscroll-toggle)
     ("l" hl-line-mode)
     ("n" display-line-numbers-mode)
     ("t" toggle-truncate-lines)
@@ -751,6 +766,10 @@ UPSTREAMS is a list of fetch URLs."
   (my/setopt-update-list
    package-archives '(("melpa" . "https://melpa.org/packages/"))))
 
+(use-package emacs
+  :custom
+  (auto-hscroll-mode 'current-line))
+
 (use-package calendar
   :custom
   (calendar-intermonth-text '(my/calendar-iso-week year month day))