indicate-buffer-boundaries

[Richard Stallman]

The interface for indicate-buffer-boundaries is really kludgy.
I cleaned up the doc for it, but I would really rather make
it simpler.

A good way to make it simpler is to use an alist.  Pick four suitable
symbols, one for each of these icons.  I suggest `top', `bottom', `up'
and `down'.  t can serve as a default for all four.  In the alist,
associate these symbols with either `left', `right' or `nil'.

Instead of current (t .  right), we would use ((top . left) (t . right))
or ((top . left) (bottom . right) (up . right) (down . right))
Instead of current (left . nil), we would use ((top . left) (bottom . left)).

Isn't that clearer?  It is much less ad-hoc.