2009/4/19 Deniz Dogan <deniz.a.m.dogan@gmail.com>:
> Hi
>
> I recently found out about the M-r keybinding, which by default is
> bound to move-to-window-line. Already knowing about the C-l keybinding
> (recenter-top-bottom) I was a bit thrown off when I found out that M-r
> doesn't behave in the same way. This got me thinking that the behavior
> of M-r should be changed to behave somewhat like C-l. So I basically
> stole the code for recenter-top-bottom and modified it to work with
> move-to-window-line instead.
>
> This is the result:
>
> (defvar move-to-window-line-last-op nil
>  "Indicates the last move-to-window-line operation performed.
> Possible values: `top', `middle', `bottom'.")
>
> (defun move-to-window-line-top-bottom (&optional arg)
>  (interactive "P")
>  (cond
>   (arg (move-to-window-line arg))                      ; Always respect ARG.
>   ((or (not (eq this-command last-command))            ; If this is
> not a repetition
>        (eq move-to-window-line-last-op 'bottom))       ; or if the last one
> put us at the bottom
>    (setq move-to-window-line-last-op 'middle)          ; then move it
> to the middle
>    (call-interactively 'move-to-window-line))
>   (t
>    (let ((this-scroll-margin
>           (min (max 0 scroll-margin)
>                (truncate (/ (window-body-height) 4.0)))))
>      (cond ((eq move-to-window-line-last-op 'middle)   ; If we're at the middle
>             (setq move-to-window-line-last-op 'top)    ; then move to the top
>             (move-to-window-line this-scroll-margin))
>            ((eq move-to-window-line-last-op 'top)      ; If we're at the top
>             (setq move-to-window-line-last-op 'bottom) ; then move to the bottom
>             (move-to-window-line (- -1 this-scroll-margin))))))))
>
> Please, do consider changing the behavior of M-r, of course not
> necessarily using the code above. If the code became a bit obfuscated
> on its way to the mailing list, I pasted it on lisp.org as well:
> http://paste.lisp.org/display/78841
>
> Thanks,
> Deniz Dogan
>

I'm guessing that no one is interested after all, but for convenience
I tried compiling a couple of patches for this change: one which adds
this functionality to lisp/window.el (and also binds it to M-r) and
one which updates etc/NEWS if it needs to be documented there.

-- 
Deniz Dogan