"C" Language Integrated Production System

 CLIPS 6.0 is an OPS-like forward chaining production system written
 in ANSI C by NASA. The CLIPS inference engine includes truth maintenance,
 dynamic rule addition, and customizable conflict resolution strategies.
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 CLIPS, including the runtime version, is easily embeddable in other
 applications. CLIPS includes an object-oriented language called COOL
 (CLIPS Object-Oriented Language) which is directly integrated with the
 inference engine.