The home for this should be:

http://www.dcs.ed.ac.uk/home/cprolog/

unfortunately the above is empty!

See old usenet post http://groups.google.com/groups?q=%2Bemas+%2Bimp+%2Bedinburgh&hl=en&selm=1991Oct21.155810.1079%40shark.uucp&rnum=3

Note it was originally written in Imp by Luis Damas.  Would be nice to
find that version.