Controlling Production Firing: The FCL Language

Abstract

While implementing a diagnostic expert system, FAITH, we have developed a new language, FCL, for controlling the firing of productions. FCL greatly simplifies the task of the user to direct this firing in a coherent and purposeful way without sacrificing some of the main advantages enjoyed by production systems. One of the interesting features of the language is the use of declarative forms to direct the firing of proper production sequences in a diagnostic expert system. Declarative forms which represent circuit diagrams and problem families control goal-directed processes like tracing through circuits and searching for symptoms to confirm or deny closely related problems. Because we have the FCL facility at our disposal, we have been able to incorporate a larger than usual number of diagnostic strategies in FAITH, with the assurance that they will be employed under the right circumstances.