🚀 go-pugleaf

There are a lot of backward chaining production systems implemented in
Prolog, because they match the nature of Prolog and it's quite easy to
implement them.  On the other hand, as far as I know, there are rather
few implementation of forward chaining production systems such as OPS5
implemented in Prolog.  The following are the examples.

Coelho, H., and Cotta, J. C.: Prolog by Example, Problem 97, Springer-
Verlag, 1988.

Shintani, T.: A Fast Prolog-Based Production System KORE/IE, Proc. of
the Fifth International Conference and Symposium on Logic Programming,
pp.26-42, 1988.

I know some other references written in Japanese.  Most of them are
naiive implementation.  The second paper above is the only one that
uses RETE-like network, so it's the only one practical.  Do you know
other references?  Thanks in advance.

-Yasusi Kanada
 yk@a.nl.cs.cmu.edu
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