How to debug this very simple Jess code? - jess

Question

(deftemplate bikelife
(slot name)
(slot type))
(deffacts bike
(bikelife (name Strida) (type low_lifestyle))
(bikelife (name Brompton) (type med_lifestyle))
(bikelife (name Molton) (type high_lifestyle))
(bikelife (name Specialized_AlleComp) (type low_sport))
(bikelife (name Specialized_Tarmac) (type medium_sport))
(bikelife (name Pinarello_DOGMA_F8) (type high_sport)))
(defrule rule-1
(budget ?x)
(test (< ?x 300))
(use_for lifestyle)
=>
(assert (recommend low_lifestyle)))
(defrule rule-2
(budget ?x)
(test (< ?x 300))
(use_for sport)
=>
(assert (recommend low_sport)))
(defrule rule-3
(budget ?x)
(test (and (> ?x 300) (< ?x <500)))
(use_for lifestyle)
=>
(assert (recommend med_lifestyle)))
(defrule rule-4
(budget ?x)
(test (and (> ?x 300) (< ?x <500)))
(use_for sport)
=>
(assert (recommend med_sport)))
(defrule rule-5
(budget ?x)
(test (> ?x 500))
(use_for lifestyle)
=>
(assert (recommend high_lifestyle)))
(defrule rule-6
(budget ?x)
(test (and (> ?x 300) (< ?x <500)))
(use_for sport)
=>
(assert (recommend med_sport)))
(defrule rule-7
(budget ?x)
(test (> ?x 500))
(use_for sport)
=>
(assert (recommend high_sport)))
(defrule recommend-rule
(recommend ?type)
(bikelife (name ?x) (type ?type))
=>
(printout t crlf "I recommend " ?x " for you." crlf crlf))
(defrule ask-1
=>
(printout t crlf "================================ ")
(printout t crlf " testing testing testing. ")
(printout t crlf "================================ " crlf crlf)
(printout t "* How much are you going to spend on bike? ")
(assert (budget (read)))
(printout t "* what purpose? ( lifestyle, sport )")
(assert (use_for (read))))
(reset)
(run)
This is my Jess code for recommending bikes. I don't see anything wrong in the code. I have tried hundreds of times and came to Stack Overflow to get some
help on it.
The code operates as I get budget value and evaluate it by 300, 500 and if the budget range matches I check the purpose of the bike the user is buying. After that using facts I want to send the recommendation message. How can I solve this problem?

Answer 1

This should more or less work except for the typos. I see a number of them, like “tyle” instead of “type”, “user_for” instead of “use_for”, and a stray “<“ before most instances of the number 500. At least the first of these three errors should be reported by Jess when you run this code.
Most of the documentation that exists is available on the Jess website, www.jessrules.com . There are a few YouTube videos if you search for them, and there’s the book “Jess in Action”; it is out of print but it’s not hard to find used copies.