In my system the user inputs a Y or N to answer simple questions. I call this rule after every question to increment a counter. There are some general problems with my code but i can't see where
(defrule QPain
(initial-fact)
=>
(printout t "Are You In Pain? " crlf)
(bind ?*Answer* (read))
)
(defrule IncSym
(test(=(str-compare (?*Answer*) "y")0))
=>
(bind ?*symcount* (+ ?*symcount* 1))
)
Thanks
The syntactic errors can be corrected as follows:
CLIPS> (clear)
CLIPS> (defglobal ?*Answer* = nil)
CLIPS> (defglobal ?*symcount* = 0)
CLIPS>
(defrule QPain
=>
(printout t "Are you in pain? ")
(bind ?*Answer* (read)))
CLIPS>
(defrule IncSym
(test (eq ?*Answer* y))
=>
(bind ?*symcount* (+ ?*symcount* 1)))
CLIPS> (reset)
CLIPS> (run)
Are you in pain? y
CLIPS> (show-defglobals)
?*Answer* = y
?*symcount* = 0
CLIPS>
This won't produce the behavior you're expecting, however, since ?*symcount* will not be incremented. The behavior of global variables and why you should not be using them in the manner you're attempting has been discussed previously:
How exactly (refresh) works in the clips?
CLIPS: forcing a rule to re-evaluate the value of a global variable?
Number equality test fails in CLIPS pattern matching?
CLIPS constant compiler directive
How can I run the clips with out reset the fact when using CLIPS
Instead of using global variables to track responses and symptoms, you should use facts or instances. Here's one approach:
CLIPS> (clear)
CLIPS>
(deftemplate symptom
(slot id)
(slot response))
CLIPS>
(deftemplate symptom-list
(multislot values))
CLIPS>
(deffacts initial
(symptom-list))
CLIPS>
(defrule QPain
=>
(printout t "Are you in pain? ")
(assert (symptom (id in-pain) (response (read)))))
CLIPS>
(defrule IncSym
(symptom (id ?id) (response y))
?f <- (symptom-list (values $?list))
(test (not (member$ ?id ?list)))
=>
(modify ?f (values ?list ?id)))
CLIPS>
(defrule symptoms-found
(declare (salience -10))
(symptom-list (values $?list))
=>
(printout t "Symptom count: " (length$ ?list) crlf))
CLIPS> (reset)
CLIPS> (run)
Are you in pain? y
Symptom count: 1
CLIPS> (reset)
CLIPS> (run)
Are you in pain? n
Symptom count: 0
CLIPS>
And another:
CLIPS> (clear)
CLIPS>
(deftemplate symptom
(slot id)
(slot response))
CLIPS>
(defrule QPain
=>
(printout t "Are you in pain? ")
(assert (symptom (id in-pain) (response (read)))))
CLIPS>
(defrule symptoms-found
(declare (salience -10))
=>
(bind ?count (find-all-facts ((?f symptom)) (eq ?f:response y)))
(printout t "Symptom count: " (length$ ?count) crlf))
CLIPS> (reset)
CLIPS> (run)
Are you in pain? y
Symptom count: 1
CLIPS> (reset)
CLIPS> (run)
Are you in pain? n
Symptom count: 0
CLIPS>