I took a look at vt tonight and while vttest still just turns
up its nose at me, it looks like I've eliminated most of the
real problems I had with Mutt and vi.  There are mainly
three changes.

First, I finally think I've got scroll() right.  Lucio's
previous patch said
> /mnt/wrap/sys/src/cmd/vt/main.c:577 c /sys/src/cmd/vt/main.c:584
> < 	draw(screen, Rpt(pt(0, dy), pt(xmax+1, ly-sy)), screen, nil, pt(0, sy));
> ---
> > 	draw(screen, Rpt(pt(0, dy), pt(xmax+1, ly+1)), screen, nil, pt(0, sy));
but it should really have dy+ly-sy in there.

Second, I made the delete to end of line and delete to end of
screen stuff work like the vt100 user's guide says it should.

Last, I changed yscrmin and yscrmax so that they are always the
beginning and end of the scrolling region even when that region
is the whole screen.  That got rid of a bunch of lines that
looked like
	M = yscrmax ? yscrmax : ymax;
Maybe there was a good reason for doing it the other way, but
I don't see it.

Anyway, attached are my current in-progress versions of vt.c
and main.c from /sys/src/cmd/vt.  They do not include the
patch Lucio posted to this list a few weeks back.  I hope
this is helpful to somebody.

Micah