coord-based recap?

[Huibai]

the java lib as we have it is a good point to branch off
into separate creations.  that is, my esteemed partner
now wants to experiment with a coordinate-based system
while i do some research/remediation work on the room-
based version :)

anyway, is there an archive of the "Coord-based system"
thread from a couple months back?  i only skimmed that
one, since i wasn't interested in it at the time.

quick q:  do you coord-basers define walls and holes as
objects or terrain types?  or how else do you implement
them?  he's working off zero knowledge on the subject
(all of that zero which i gave him ;) having zero myself),
and just maybe i can persuade him to post and stop
lurking on here if he can see some ideas other than his
bounced around.

-John G.
 (for Dan!)