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What is CLIPS?

CLIPS (C Language Integrated Production System) is a forward-chaining rule-based programming language designed for building expert systems. It was developed at NASA’s Johnson Space Center and is particularly well-suited for implementing AI game logic. The Mouse and Cats game leverages CLIPS’ pattern matching and rule-based inference engine to create intelligent cat AI that can trap the mouse player.

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Version Requirement

This game requires CLIPS 6.4 to run properly. Make sure you have the correct version installed.

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Basic CLIPS Syntax

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Comments

; Single line comment starts with semicolon

; Multi-line documentation comments
; are just multiple single-line comments

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Facts and Templates

Facts are the basic data units in CLIPS. Templates define the structure of facts: 
(deftemplate person
  "Defines a person"
  (slot name (type STRING))
  (slot age (type NUMBER))
)

; Creating a fact
(assert (person (name "John") (age 30)))

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Rules

Rules define conditional logic that fires when patterns match: 
(defrule example-rule
  "Rule documentation"
  ?fact <- (condition-pattern)
  =>
  (printout t "Action executed" crlf)
  (retract ?fact)
)

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Functions

Functions encapsulate reusable logic: 
(deffunction my-function (?param1 ?param2)
  "Function documentation"
  (+ ?param1 ?param2)
)

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Running CLIPS Commands

Once you have CLIPS 6.4 installed and the game loaded:

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Starting the Game

; View instructions first
(instrucciones)

; Or jump straight into playing
(jugar)

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Common CLIPS Commands

; Load the game file
(load "raton_y_gatos.clp")

; Reset the environment
(reset)

; Run all activated rules
(run)

; View all facts
(facts)

; View all rules
(rules)

; Clear the screen
(clear-window)

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Interactive Game Commands

During gameplay:
  • Enter row number (1-8) when prompted for mouse movement
  • Enter column number (1-8) to complete the move
  • The cats will automatically respond with AI-calculated moves

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Official CLIPS Documentation

For comprehensive CLIPS language reference:

CLIPS Documentation

Official CLIPS 6.4 documentation, user guide, and reference manual

CLIPS Expert System

Main CLIPS website with downloads and resources

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Key CLIPS Features Used in This Game

  • Pattern Matching: Matching board states to trigger appropriate AI moves
  • Forward Chaining: Rules automatically fire when conditions are met
  • Salience: Priority levels for rules (e.g., endgame detection has highest priority)
  • Fact Modification: Updating board state by modifying casilla facts
  • Procedural Functions: Game setup and instruction display functions

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