I thought about this once before, but the recent discussion about
viper/vimpact reminded me.  Has anyone made an ed-mode, as in an
emulator for ed, THE STANDARD TEXT EDITOR
(http://www.gnu.org/fun/jokes/ed.msg.html).  I just thought it might be
a fun way to learn some emacs lisp.

Does anyone know if this has been done?

So far, I intend to show the file/buffer being edited in one window, and
the ed "interface" in the other window.  A couple other things I'm
wondering:

How do I locally override ALL keys, like a wildcard?  I need to reject
all invalid keys with ? in command mode, so I thought it would best to
reject all, then selectively allow valid keys.  I think this will also
keep them from trying to manipulate the interface manually?

Is there some mode/function that's really worth overriding?  I thought
about it, but I figured it would be best done from scratch, (as a minor
mode?).  I'm still kind of vague on this, though.

Any other ideas welcome. :)

Matthew Flaschen