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GoalVariable Statement (for backward chaining)

When the inference method is set to Backward, use this statement to identify the variable for which the inference engine is to solve.

The GoalVariable statement, when required, must appear immediately after the Variables(...) section of the ruleset.


    RuleSet <nameOfRuleSet> (

      <Processing Options Statement>*      // Zero or more statements

      Variables(
        <Variable Declaration Statement>+  // One or more statements
      )

      GoalVariable(...)

      .
      .
      .
    )
      

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GoalVariable

Specifies the variable for which the backward chaining inference engine is to solve. GoalVariable is a required statement when InferenceMethod(Backward) is specified. For other inference methods, the statement must not be used.

Syntax

   GoalVariable ( <variableName> )
      

Parameters

       <variableName>
Is an identifier that names a previously defined variable.

Example


    RuleSet <nameOfRuleSet> (

      InferenceMethod(Backward)

      Variables(
         Diagnosis string("unknown")
         ...
       )

       GoalVariable(Diagnosis) // The backward chaining inference engine
                               //   tries to determine the diagnosis.

      .
      .
      .
    )
      
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Last modified: Thu Mar 29 14:50:28 CST 2001