CLIPS 6.4.1专家系统程序问题：双“no”输入未触发预期输出

我编写了一段用于构建专家系统的CLIPS代码，运行代码并对两个问题均回答“no”时，未得到任何输出，但预期程序应打印“You are likely a teen.”。使用的CLIPS版本为6.4.1。

原代码 #

(defrule ask-question-1
  =>
  (printout t "Do you have a full-time job or go to school full-time? (yes/no): ")
  (assert (full-time-occupation (read)))
)

(defrule ask-question-2
  =>
  (printout t "Do you have a driver's license? (yes/no): ")
  (assert (has-drivers-license (read)))
)

(defrule determine-age
  (and (full-time-occupation yes) (has-drivers-license yes))
  =>
  (printout t "You are likely an adult." crlf)
)

(defrule determine-age
  (and (full-time-occupation no) (has-drivers-license no))
  =>
  (printout t "You are likely a teen." crlf)
)

(defrule determine-age
  (and (full-time-occupation no) (has-drivers-license yes))
  =>
  (printout t "You are likely a teen." crlf)
)

(defrule determine-age
  (and (full-time-occupation yes) (has-drivers-license no))
  =>
  (printout t "You are likely an adult." crlf)
)

问题原因 #

问题出在重复定义了同名规则determine-age。在CLIPS中，多次定义同名规则时，后续的规则会直接覆盖之前的同名规则。最终只有最后一个determine-age规则（匹配full-time-occupation yes且has-drivers-license no的情况）会被保留，前面三个规则都被替换掉了。当你对两个问题都回答“no”时，没有匹配的规则触发，因此不会输出预期内容。

修复方案 #

有两种可行的修复方式：

方式1：给每个规则设置唯一名称

(defrule determine-age-adult-both-yes
  (and (full-time-occupation yes) (has-drivers-license yes))
  =>
  (printout t "You are likely an adult." crlf)
)

(defrule determine-age-teen-both-no
  (and (full-time-occupation no) (has-drivers-license no))
  =>
  (printout t "You are likely a teen." crlf)
)

(defrule determine-age-teen-license-yes
  (and (full-time-occupation no) (has-drivers-license yes))
  =>
  (printout t "You are likely a teen." crlf)
)

(defrule determine-age-adult-license-no
  (and (full-time-occupation yes) (has-drivers-license no))
  =>
  (printout t "You are likely an adult." crlf)
)

方式2：合并条件简化规则

将同类结果的条件合并到一个规则中，用or逻辑减少冗余：

(defrule determine-age-adult
  (or
    (and (full-time-occupation yes) (has-drivers-license yes))
    (and (full-time-occupation yes) (has-drivers-license no))
  )
  =>
  (printout t "You are likely an adult." crlf)
)

(defrule determine-age-teen
  (or
    (and (full-time-occupation no) (has-drivers-license no))
    (and (full-time-occupation no) (has-drivers-license yes))
  )
  =>
  (printout t "You are likely a teen." crlf)
)

内容的提问来源于stack exchange，提问作者Fatima A