Q: How can I swap buffers in two windows?

Q: How can I swap buffers in two windows?

[Eric Pement]

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.

--
Eric Pement

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

[Sebastian Luque]

"Eric Pement" <pemente@northpark.edu> 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?

Perhaps not exactly what you want, but this might help:

http://www.emacswiki.org/cgi-bin/wiki/buffer-move.el


Cheers,

-- 
Sebastian P. Luque

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)))

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

[Eric Pement]

Lennart Borgman wrote:
> Eric Pement wrote:
>
> > [ ... ] 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.

> Something like this perhaps:
>
> (defun rotate-window-buffers()
[ ... ]

Great! No error message, but it seems to work in the brief testing that
I've done. Thanks, you've been a great help!!

--
Eric Pement