Re: default-indicate-buffer-boundaries

[Luc Teirlinck]

Kim Storm wrote:

   We could put the indicator on the next line in those case.

Would be confusing for the end-of-buffer indicator.  Also the entire
buffer could be one single continued line.

   Or we could combine those two bitmaps (there is already code
   which allows two bitmaps to be shown at the same time, like
   a breakpoint icon and the overlay arrow.)

The indicate-buffer-boundary bitmaps already "combine" with the
overlay arrow right now, although the result does not really look that
great.  I did not test how they interact with breakpoint bitmaps.

One should not concentrate too exclusively on the testcases I
provided.  There is a general problem here.  Both fringes are used for
continuation/truncation.  The left fringe is also used for the overlay
arrow and breakpoints.  The fringes are probably still used for
additional stuff I can not think of right now.

Whenever one wants to show something to the user without hiding any
part of the buffer, the "obvious" solution is to put a bitmap in one
of the two fringes, if fringe mode is enabled.  But the problem is
that there is not that much space in the fringe, so conflicts result.

There is a lot that the fringes potentially _could_ be useful for, but
they can not _actually_ be used for a lot.  Hence, I believe that one
should be very reluctant to put any bitmaps other than the
continuation/truncation and overlay/breakpoint bitmaps (and
occasionally point) in the fringes _by default_.  It is OK for
non-default features to put icons in the fringe, since the user who
enables the feature explicitly indicates that the feature is important
enough to him to be willing to live with the potential conflicts.

The indicate-empty-lines bitmaps do not conflict with anything else in
the fringe, because they only are put on empty lines.  They indicate
end of buffer whitespace more clearly than the
indicate-buffer-boundaries icons.  (In practice, I personally still
needed them, _even_ with indicate-buffer-boundaries enabled.)  I
believe to remember that Miles, the only person complaining about them
being "too much in your face" uses a non-default fringe background color.

So I believe that enabling `indicate-empty-lines' by default would be
more useful, without creating any problems.  I believe that the extra
info provided by `indicate-buffer boundaries' (showing _beginning_ of
buffer) is not sufficiently important to sufficiently many people to
put all these bitmaps in the fringe _by default_.

Sincerely,

Luc.