+2012-10-10 Martin Rudalics <rudalics@gmx.at>
+
+ * window.el (switch-to-buffer-preserve-window-point): New option.
+ (switch-to-buffer): Obey
+ `switch-to-buffer-preserve-window-point' (Bug#4041).
+
2012-10-09 Stefan Monnier <monnier@iro.umontreal.ca>
* newcomment.el (comment-start-skip, comment-end-skip, comment-end):
buffer))
(other-buffer)))
+(defcustom switch-to-buffer-preserve-window-point nil
+ "If non-nil, `switch-to-buffer' tries to preserve `window-point'.
+If this is nil, `switch-to-buffer' displays the buffer at that
+buffer's `point'. If this is `already-displayed', it tries to
+display the buffer at its pevious position in the selected
+window, provided the buffer is currently displayed in some other
+window on any visible or iconified frame. If this is t, it
+unconditionally tries to display the buffer at its previous
+position in the selected window.
+
+This variable is ignored if the the buffer is already displayed
+in the selected window or never appeared in it before, or if
+`switch-to-buffer' calls `pop-to-buffer' to display the buffer."
+ :type '(choice
+ (const :tag "Never" nil)
+ (const :tag "If already displayed elsewhere" already-displayed)
+ (const :tag "Always" t))
+ :group 'windows
+ :version "24.3")
+
(defun switch-to-buffer (buffer-or-name &optional norecord force-same-window)
"Switch to buffer BUFFER-OR-NAME in the selected window.
If the selected window cannot display the specified
must be displayed in the selected window; if that is impossible,
signal an error rather than calling `pop-to-buffer'.
+The option `switch-to-buffer-preserve-window-point' can be used
+to make the buffer appear at its last position in the selected
+window.
+
Return the buffer switched to."
(interactive
(list (read-buffer-to-switch "Switch to buffer: ") nil 'force-same-window))
(if force-same-window
(user-error "Cannot switch buffers in a dedicated window")
(pop-to-buffer buffer norecord)))
- (t (set-window-buffer nil buffer)))
+ (t
+ (let* ((entry (assq buffer (window-prev-buffers)))
+ (displayed (and (eq switch-to-buffer-preserve-window-point
+ 'already-displayed)
+ (get-buffer-window buffer 0))))
+ (set-window-buffer nil buffer)
+ (when (and entry
+ (or (eq switch-to-buffer-preserve-window-point t)
+ displayed))
+ ;; Try to restore start and point of buffer in the selected
+ ;; window (Bug#4041).
+ (set-window-start (selected-window) (nth 1 entry) t)
+ (set-window-point nil (nth 2 entry))))))
(unless norecord
(select-window (selected-window)))