Пример 9.9. Правила determine-low-output и determine-point-surface-state

(defrule determine-low-output " "

(working-state engine unsatisfactory)

(not (symptom engine low-output | not-low-output))

(not (repair?))

=>

(if (yes-or-no-p " Is the output of the engine low (yes/no)? ")

then

(assert (symptom engine low-output))

else

(assert (symptom engine not-low-output)))

)

(defrule determine-point-surface-state " "

(or (and (working-state engine does-not-start)

(spark-state engine irregular-spark))

(symptom engine low-output))

(not (repair?))

=>

(bind? response (ask-question " What is the surface state of the

points (normal /burned /contaminated)? "

normal burned contaminated))

(if (eq? response burned)

then

(assert (repair " Replace the points."))

else

(if (eq? response contaminated)

then

(assert (repair " Clean the points."))))

)

Правило determine-low-output определяет, имеет ли место низкая мощность двигателя или нет. Правило determine-point-surface-state адекватно реаги­рует на условия, заданные в правилах 7 и 12. Обратите внимание на исполь­зование условных элементов or и and, которые обеспечивают одинаковое поведение правила в двух абсолютно разных ситуациях. Кроме того, прави­ло determine-point-surface-state отличается от приведенных ранее тем, что непосредственно использует функцию ask-question, вместо yes-or-no-p, т. к. в данный момент пользователю задается вопрос, подразумевающий три варианта ответа.

Реализация оставшихся диагностических правил (8—11) также не должна вызвать у вас затруднений.

Пример 9.10. Оставшиеся диагностические правила

(defrule determine-conductivity-test " "

(working-state engine does-not-start)

(spark-state engine does-not-spark)

(charge-state battery charged)

(not (repair?))

=>

(if (yes-or-no-p " Is the conductivity test for the ignition coil positive(yes/no)? ")

then

(assert (repair " Repair the distributor lead wire."))

else

(assert (repair " Replace the ignition coil.")))

)

(defrule determine-sluggishness " "

(working-state engine unsatisfactory)

(not (repair?))

=>

(if (yes-or-no-p " Is the engine sluggish (yes/no)? ") then

(assert (repair " Clean the fuel line.")))) (defrule determine-misfiring " "

(working-state engine unsatisfactory) (not (repair?))

(if (yes-or-no-p " Does the engine misfire (yes/no)? ")

then

(assert (repair " Point gap adjustment."))

(assert (spark-state engine irregular-spark)))

)

(defrule determine-knocking " "

(working-state engine unsatisfactory)

(not (repair?))

=>

(if (yes-or-no-p " Does the engine knock (yes/no)? ")

then

(assert (repair " Timing adjustment.")))

)