From cd31c3cb423baaaa9f7f3fa9eab274c09f2db1e9 Mon Sep 17 00:00:00 2001
From: James Thomas <jimjoe@gmx.net>
Date: Mon, 16 Jun 2025 01:20:31 +0530
Subject: [PATCH] Add 'other-window-backward' for a default binding (bug#78803)

This moves in the opposite direction to 'other-window' by
default, and is consistent with its repeat map.
* lisp/window.el (other-window-backward): New function bound to
'C-x O'.
(ctl-x-map): Update definition.
* doc/emacs/windows.texi (Other Window): Update docs.
* etc/NEWS: Annouce the new command.
---
 doc/emacs/windows.texi |  5 ++++-
 etc/NEWS               |  4 ++++
 lisp/window.el         | 14 ++++++++++----
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/doc/emacs/windows.texi b/doc/emacs/windows.texi
index 9473f189c25..4f04dc542eb 100644
--- a/doc/emacs/windows.texi
+++ b/doc/emacs/windows.texi
@@ -158,6 +158,8 @@ this option is @code{nil}.
 @table @kbd
 @item C-x o
 Select another window (@code{other-window}).
+@item C-x O
+Select another window, backwards (@code{other-window-backward}).
 @item C-M-v
 Scroll the next window upward (@code{scroll-other-window}).
 @item C-M-S-v
@@ -183,7 +185,8 @@ cycle in the opposite order.  When the minibuffer is active, the
 minibuffer window is the last window in the cycle; you can switch from
 the minibuffer window to one of the other windows, and later switch
 back and finish supplying the minibuffer argument that is requested.
-@xref{Minibuffer Edit}.
+@xref{Minibuffer Edit}. @kbd{C-x O} is similar, but defaults to the
+opposite order.
 
 @findex next-window-any-frame
 The @code{other-window} command will normally only switch to the next
diff --git a/etc/NEWS b/etc/NEWS
index 3b9e06f99d9..e12a9dcb127 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -333,6 +333,10 @@ helps to restore window buffers across Emacs sessions.
 You can use this in 'display-buffer-alist' to match buffers displayed
 during the execution of particular commands.
 
+*** New command 'other-window-backward' ('C-x O').
+This moves in the opposite direction of 'other-window' and is for its
+default keybinding consistent with 'repeat-mode'.
+
 ** Frames
 
 +++
diff --git a/lisp/window.el b/lisp/window.el
index 44cb682d6dd..512e85dc29a 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -4073,6 +4073,14 @@ nil, which considers all windows on the selected frame."
 	;; Always return nil.
 	nil))))
 
+(defun other-window-backward (count &optional all-frames interactive)
+  "Select another window in the reverse cyclic ordering of windows.
+COUNT specifies the number of windows to skip, (by default) backward,
+starting with the selected window, before making the selection.  Like
+`other-window', but moves in the opposite direction."
+  (interactive "p\ni\np")
+  (other-window (- (or count 1)) all-frames interactive))
+
 (defun other-window-prefix ()
   "Display the buffer of the next command in a new window.
 The next buffer is the buffer displayed by the next command invoked
@@ -11373,6 +11381,7 @@ found by the provided context."
 (define-key ctl-x-map "2" 'split-window-below)
 (define-key ctl-x-map "3" 'split-window-right)
 (define-key ctl-x-map "o" 'other-window)
+(define-key ctl-x-map "O" 'other-window-backward)
 (define-key ctl-x-map "^" 'enlarge-window)
 (define-key ctl-x-map "}" 'enlarge-window-horizontally)
 (define-key ctl-x-map "{" 'shrink-window-horizontally)
@@ -11386,10 +11395,7 @@ found by the provided context."
   :doc "Keymap to repeat `other-window'.  Used in `repeat-mode'."
   :repeat t
   "o" #'other-window
-  "O" (lambda ()
-        (interactive)
-        (setq repeat-map 'other-window-repeat-map)
-        (other-window -1)))
+  "O" #'other-window-backward)
 
 (defvar-keymap resize-window-repeat-map
   :doc "Keymap to repeat window resizing commands.