Question

说我已经定义了一个模板和一些事实，如下所示：

(deftemplate student
    (slot name (type SYMBOL) (default ?NONE))
    (slot grade (type SYMBOL) (default C) (allowed-symbols A B C D))
    (slot graduated (type SYMBOL) (default no) (allowed-symbols yes no))
)

(deffacts insert-facts
    (student (name George) (grade A))
    (student (name Nick) (grade C))
    (student (name Bob))
    (student (name Mary) (grade B))
)

假设我想创建一个规则来检查每个学生的成绩将相应的分级变量设置为符号“是”＆＃39;。我怎么能这样做？

Answer 1

这是您为解决问题而提出的规则略微冗长的版本：

CLIPS> 
(deftemplate student
    (slot name (type SYMBOL) (default ?NONE))
    (slot grade (type SYMBOL) (default C) (allowed-symbols A B C D))
    (slot graduated (type SYMBOL) (default no) (allowed-symbols yes no)))
CLIPS> 
(deffacts insert-facts
    (student (name George) (grade A))
    (student (name Nick) (grade C))
    (student (name Bob))
    (student (name Mary) (grade B)))
CLIPS> 
(defrule rule-1
   ?s <- (student (grade A|B) (name ?n) (graduated ~yes))
   =>
   (modify ?s (graduated yes))
   (printout t "Congratulations " ?n "!" crlf))
CLIPS> (reset)
CLIPS> (run)
Congratulations Mary!
Congratulations George!
CLIPS>

Answer 2

我已经解决了这个问题。我把它留在这里以防其他人需要它。

我已按以下方式创建规则

(defrule rule-1
    ?s <- (student (grade ?g&A|B) (name ?n) (graduated ?gr) (classified ?c&no))
=>
    (retract ?s)
    (assert (student (name ?n)(grade ?g) (graduated yes) (classified yes)))
    (printout t "Congratulations " ?n "!" crlf)
)

并以下列方式修改了学生模板，以防止程序陷入无限循环。

(deftemplate student
    (slot name (type SYMBOL) (default ?NONE))
    (slot grade (type SYMBOL) (default C) (allowed-symbols A B C D))
    (slot graduated (type SYMBOL) (default no) (allowed-symbols yes no))
    (slot classified (type SYMBOL) (default no) (allowed-symbols yes no))
)

修改触发规则的当前事实

2 个答案: