bug#3366: 23.0.94; doc of split-window-preferred-function, display-buffer, etc.

[martin rudalics]

> It seems (but I'm not sure this works for all cases) that what is
> needed, to ensure that the same window as before is split, is to bind
> `split-window-preferred-function' to something like this around calls
> to `display-buffer':
>
> (lambda (w) (eq w (get-lru-window)))

The function you want might be

(defun split-window-22 (window)
  (let ((frame (window-frame window)))
    (or (and (setq window (get-largest-window frame t))
             (window-full-width-p window)
             (window-splittable-p window)
             (split-window window))
        (and (setq window (get-lru-window frame t))
             (window-splittable-p window)
             (split-window window)))))

but I wouldn't rely on it.

> Even if this function is not an exact recipe for all cases, something
> like it should be mentioned, to help users get back the behavior that
> existed before the new "smarter" behavior was introduced.  Preferably,
> Emacs would itself provide a function that users could use here - a
> function that would give precisely the pre-23 behavior in all cases.
>
> We should also make it clear that if you want the pre-23 behavior then
> you will need to wrap not only explicit calls to `display-buffer' with
> a `let' binding this way, but also calls to things such as
> `with-output-to-temp-buffer'.

All people have to do is customize `split-window-preferred-function' to
that function.

martin