Re: Windows' "split status"

[Chong Yidong <cyd@gnu.org>]

martin rudalics <rudalics@gmx.at> writes:

> The problem with window parameters is that I currently do save them
> together with a window configuration and restore them when restoring
> the configuration.  Earlier, Stefan didn't want to do that and I'd
> like to revert the current behavior at any time when problems arise.
> This would mean, however, that when you have a nested window, dissolve
> it within a window excursion, and restore the initial configuration,
> the nesting would get lost.  So I'd rather be on the safe side in this
> regard.

Not a problem; if we do revert the behavior, we can bring back the
special slot and the old code.  I'd rather we try to DTRT now.

> OTOH, it's not entirely trivial to handle `window-max-children' during
> recombination.  Suppose you have a configuration like
>
>  -------------------
> |    |    | W3 | W4 |
> | W1 | W2 |---------|
> |    |    |    W5   |
>  -------------------
>
> the user has set `window-max-children' to 3 and deletes W5.  How should
> recombine_windows proceed?

If I understand your example, this corresponds to the window tree

       root (internal)
        |
   ----------
  |     |    |
  W1    W2   W6 (internal)
             |
         ---------
         |       |
        W5     --W7 (internal)
               |    |
              W3    W4

On deleting W5 with `window-max-children' of 3, the tree becomes

       root (internal)
        |
   ----------
  |     |    |
  W1    W2   W7 (internal)
             |
          ------
          |    |
         W3    W4

which is reasonable.

As for the case where `window-max-children' has been set to 2 (e.g. by
changing the option midway through an Emacs session), that can be
handled by treating it as a soft limit: Emacs will not *add* children to
an internal window past the number specified by `window-max-children'
(or the window parameter), but if an internal window winds up with
excess children for any reason, Emacs does not try to prune it or
rearrange the window tree.

Does that make sense?