剪辑：避免连接约束

Question

假设我们有以下CLIPS模板和规则：

;; The queue sequence starts at 0.
;; -1 is a placeholder value to identify a newly inserted element.
;; The idea is to put a newly inserted element at the end of the queue.
(deftemplate queue-element
    (slot order (type INTEGER) (default -1))

(deftemplate put-at-the-end
    ?e1 <- (queue-element (order -1))
    ?e2 <- (queue-element (order ?o1))
    (not (queue-element (order ?o2&:(> ?o2 ?o1))))
  =>
    (modify ?e1 (order (+ ?o1 + 1))))

有没有办法将“连接约束”(> ?o2 ?o1)移出模式并将其移动到类似于(test (> ?o2 ?o1))构造的东西？

我们的想法是完全避免这些在线条件。

Answer 1

您可以使用和条件元素在非条件元素中放置多个条件元素。

CLIPS> 
(deftemplate queue-element
    (slot order (type INTEGER) (default -1)))
CLIPS> 
(defrule put-at-the-end
    ?e1 <- (queue-element (order -1))
    ?e2 <- (queue-element (order ?o1))
    (not (and (queue-element (order ?o2))
              (test (> ?o2 ?o1))))
  =>
    (modify ?e1 (order (+ ?o1 1))))
CLIPS>