1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
|
(defrule push-value
?push-value <- (push-value ?name ?value)
?stack <- (stack ?name $?rest)
=>
(retract ?push-value ?stack)
(assert (stack ?name ?value $?rest))
(printout t "Pushing value " ?value " from stack " ?name crlf))
(defrule pop-value-valid
?pop-value <- (pop-value ?name)
?stack <- (stack ?name ?value $?rest)
=>
(retract ?pop-value ?stack)
(assert (stack ?name $?rest))
(printout t "Popping value " ?value " from stack " ?name crlf))
(defrule pop-value-invalid
?pop-value <- (pop-value ?name)
(stack ?name)
=>
(retract ?pop-value)
(printout t "Attempting to pop an empty stack: " ?name crlf))
(deffacts initial-setup
(stack letters a b c) ; initial stacks
(stack numbers 1 2)
(push-value letters d) ; initial actions on stacks
(pop-value numbers)
)
|
