🚀 go-pugleaf

In article <GARY.89Jan24170950@milo.mcs.clarkson.edu> gary@milo.mcs.clarkson.edu (Gary Levin) writes:
>Does anyone have access to source for IC-Prolog or any of its
>descendants?  What machines will it run on?

The answer is probably NO. I asked Frank McCabe, the author, last
year if he had the sources and he said he hadn't. So I haven't
included it my list of live Prolog systems ever since. Although
Imperial College doesn't appear to have a copy, it was distributed to
various people and it's quite possible that some people on the net
have copies stacked away on old mag tapes.  Any offers?

It was written in fairly standard Pascal--at the time it mainly ran on the
college Cyber machines. If it'll run on them it'll run on anything!
The main reason it was abandoned was the slowness and inconvenience of the 
pure system. For instance, to do i/o you had to construct a difference list
(without even DCG's) and associate this with a channel. Multimode 
arithmetic is simple in comparison: sum(X,Y,Z) always gives solutions.
The problem is that if it is non-deterministic you have to generate solutions
in a preconceived order, and this is nearly always useless.
(MicroProlog was a sort of descendent which has this feature minus the
nondeterminism and is cheaply available.)

The only approach I've seen which handles those issues sensibly so far is
Trilogy, and that simply keeps predicates and functions pure of side effects
while allowing you to code up those things in dirty "subr"s; that has its
advantages. You can debug predicates knowing they are pure. It doesn't help
with debugging the subr's. Arithmetic is handled via constraints.

Chris Moss.