Re: Better handling of window margins

[Eli Zaretskii <eliz@gnu.org>]

> From: Joost Kremers <joostkremers@fastmail.fm>
> Cc: martin rudalics <rudalics@gmx.at>, emacs-devel@gnu.org
> Date: Wed, 02 Dec 2015 20:52:51 +0100
> 
> > In any case, the same problem exists if this is somehow guessed.  The
> > infrastructure cannot know enough about the modes to make a decision.
> 
> Speaking as a minor-mode author, I would expect Emacs to provide a
> default that handles the known cases in a reasonable manner, the known
> cases IMHO being those I described.

If we are fairly sure these 2 use cases cover most of the ground,
perhaps.  Are we sure?  If we aren't, then building non-trivial
infrastructure tailored to just 2 use cases doesn't sound like a good
design strategy to me.

> >>  >   . for splitting the window as result of some command calling
> >>  >     display-buffer, we could expect the modes to customize the
> >>  >     display-buffer-* variables to control how the window is split (if
> >>  >     there are currently no features/variables to that effect, we should
> >>  >     add them)
> >> 
> >> When two modes simultaneously use the margins, which buffer display
> >> function would be chosen?
> >
> > The same problem exists with the proposed solution, doesn't it?
> 
> If the value of `set-window-margins-function' is a single function, then
> probably the function provided by the last mode to be activated in a
> buffer.
> 
> Isn't that a potential problem?

Yes, that's exactly what I meant -- the problem with choosing between
several potentially conflicting requests exists, and should somehow be
solved.