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A programming language for rule-based production systems. A rule consists of pre-condition(s) and a resulting action.

The system checks its working memory to see if there are rules whose pre-conditions are satisfied, if so, the action in one selected satisfied rule is executed.

There is a public domain implementation of an OPS5 interpreter written by Charles L. Forgy <forgy@cs.cmu.edu> in 1977. It was first implemented in Lisp and later in BLISS. It was also ported to Common Lisp by George Wood and Jim Kowalski.

CLIPS is a language for writing expert systems, with some of the capabilities of OPS5.

See also C5, OPS83, OPS4, OPS5+, OPS83.

Inference Engine Tech, Cambridge MA.

An OPS5 interpreter in Common LISP.

A version by Mark Kantrowitz. <mkant+@cs.cmu.edu>.

["Programming Expert Systems in OPS5", L. Brownston et al, A-W 1985].

["An OPS5 Primer", Sherman et al, comes with OPS5 for DOS].

["Rule-Based Programming in the Unix System", G.T. Vesonder, AT&T Tech J 67(1), 1988].
References in periodicals archive ?
Like OPS5, they all provide the benefits of a is many times as fast and much smaller than the Lisp version but is quite expensive and available only for DEC
As a result, ART supports a much richer pattern matching syntax than does OPS5 and supports free access to external routines within both the conditions and actions of rules.
Many AI practitioners were quite surprised that ART was able to compete with Bliss OPS5 in terms of performance.
After benchmarking many expert system shells and rule-based programming languages, NASA standardized on Rete Algorithm-based production systems and selected ART over OPS5, presumably because ART is more expressive and more functional.
CLIPS rules language, and its Java version, JESS, are based on the early work of Haley System's founder, Paul Haley, who worked on OPS5 and ART rules languages, the basis for NASA's CLIPS.
DEC OPS5, an expert system development environment for constructing rule-based applications, available in May.