嵌套多个如果是else语句

Question

我正在尝试制定一个剪辑程序，以吸收患者和捐助者的血型，并在医生输血前进是否返回。当我加载程序时，我在最后会得到一个错误的标志。有其他方法可以嵌套在当时的语句中吗？

; define template
    
(deftemplate blood-type
   (slot blood))
    
(deftemplate patients
   (slot receiver)
   (slot donor))
        
; reading input
    
(defrule reading-input    
   => 
   (printout t "Enter the receiver/patient blood type: ")  
   (assert (receiver (read))) 
   (printout t "Enter the donor's blood type: ") 
   (assert (donor (read))))
        
; checking for valid input
    
(defrule checking-input    
   (receiver ?receiver)
   (donor ?donor) 
   => 
   (if (and (eq ?receiver O) (eq ?donor O)) 
      then     
      if (and (eq ?receiver A) (eq ?donor A))
        then
        (if (and (eq ?receiver A)(eq ?donor O))
           then
           (if (and (eq ?receiver B) (eq ?donor B))
              then
              (if (and (eq ?receiver B) (eq ?donor O))
                 then
                 (if (and (eq ?receiver AB) (eq ?donor AB))
                    then
                    (if (and (eq ?receiver AB) (eq ?donor A))
                       then
                       (if (and (eq ?receiver AB) (eq ?donor B))   
                          then
                          (if (and (eq ?receiver AB) (eq ?donor O))
                             then (printout t "Continue with Transfusion" crlf)
                             else (printout t "Stop transfusion" crlf))))))))))

Answer 1

您的条件筑巢非常复杂。您可以在没有任何嵌套的情况下获得正确的结果：

         CLIPS (6.4 2/9/21)
CLIPS>
(defrule read-and-check-input    
   => 
   (printout t "Enter the receiver/patient blood type: ")  
   (bind ?receiver (read)) 
   (printout t "Enter the donor's blood type: ") 
   (bind ?donor (read))
   (if (or (and (eq ?receiver O) (eq ?donor O)) 
           (and (eq ?receiver A) (eq ?donor A))
           (and (eq ?receiver A)(eq ?donor O))
           (and (eq ?receiver B) (eq ?donor B))
           (and (eq ?receiver B) (eq ?donor O))
           (and (eq ?receiver AB) (eq ?donor AB))
           (and (eq ?receiver AB) (eq ?donor A))
           (and (eq ?receiver AB) (eq ?donor B))   
           (and (eq ?receiver AB) (eq ?donor O)))
      then (printout t "Continue with Transfusion" crlf)
      else (printout t "Stop transfusion" crlf)))
CLIPS> (reset)
CLIPS> (run)
Enter the receiver/patient blood type: A
Enter the donor's blood type: O
Continue with Transfusion
CLIPS> (reset)
CLIPS> (run)
Enter the receiver/patient blood type: B
Enter the donor's blood type: AB
Stop transfusion
CLIPS>

如果这是用于课堂分配的，则可能会使用不使用有意义的方式使用模式匹配的方法获得失败的成绩。