Re: Q: How can I swap buffers in two windows?

[Lennart Borgman]

Eric Pement wrote:

> This request has appeared several times on this newsgroup, worded in
> different ways, but has never been answered. I have already checked the
> FAQ, M-x apropos, and the Emacs info pages. Can someone please give
> help or direction here?
>
> I have an Emacs frame split into two windows, which may be split
> vertically or horizontally. I would like a single command to swap or
> exchange both windows, i.e., put buffer A into window B, and put buffer
> B into window A. If there are not exactly two windows in the frame,
> issue an error message.
>
> I know that I can do "C-x b", {B}, <RET>, "C-x o", "C-x b", {A}, <RET>,
> but I want to execute it with a single command without typing out the
> buffer names at all. Emacs already knows the names of the buffers in
> each window, so why should I have to type them?
>
> My elisp skills are not well-developed, so I'm asking for help. I have
> GNU Emacs version 21.3.50.8. Thanks in advance.
>  
Something like this perhaps:

(defun rotate-window-buffers()
 (interactive)
 (let* ((windows (window-list))
        (buffers (mapcar (lambda(w)
                           (window-buffer w))
                         windows))
        (wpoints (mapcar (lambda(w)
                           (window-point w))
                         windows))
        (w (pop windows))
        )
   (setq windows (reverse windows))
   (push w windows)
   (setq windows (reverse windows))
   (mapc (lambda(w)
           (let ((b (pop buffers))
                 (p (pop wpoints)))
             (set-window-buffer w b)
             (set-window-point w p)))
         windows)))