How to sort people in JESS? - jess

Question

This is the code of my program to sort people gender wise and age wise. I am getting the output but not as expected.
(deffacts initial-phase
(phase choose-gender)
(phase choose-age)
(phase choose-name))
(deffacts person (gender) (age) (name))
(deffunction ask-start-again ()
(printout t "Enter another person? (y/n) ")
(if (eq (read) y) then
(assert (phase choose-gender)
(phase choose-age)
(phase choose-name))))
(deffunction comparePerson(?pa ?pb $?comp)
(if (< ((nth$ 1 $?comp) ?pa ?pb) 0) then (return -1))
(if (> ((nth$ 1 $?comp) ?pa ?pb) 0) then (return 1))
(if (= (length$ $?comp) 1) then (return 0))
(return (comparePerson ?pa ?pb (rest$ $?comp))))
;RULES
(defrule gender-select
(phase choose-gender)
=>
(printout t "what is your gender (Male: m "
"Female: f)? ")
(assert (gender-select (read))))
(defrule good-gender-choice
?phase <- (phase choose-gender)
?choice <- (gender-select ?gender&:(or (eq ?gender m) (eq ?gender f)))
=>
(retract ?phase ?choice)
(assert (gender ?gender))
(assert (phase select-age)))
(defrule bad-gender-choice
?phase <- (phase choose-gender)
?choice <- (gender-select ?player&~m&~f)
=>
(retract ?phase ?choice)
(assert (phase choose-gender))
(printout t "Choose m or f." crlf))
(defrule age-select
(phase select-age)
=>
(printout t "What is your age? ")
(assert (age-select (read))))
(defrule good-age-choice
?phase <- (phase select-age)
?choice <- (age-select ?age&:(integerp ?age)
&:(> ?age 0))
=>
(retract ?phase ?choice)
(assert (age ?age))
(assert (phase select-name)))
(defrule bad-age-choice
?phase <- (phase select-age)
?choice <- (age-select ?age&:(or (not (integerp ?age))
(<= ?age 0)))
=>
(retract ?phase ?choice)
(assert (phase select-age))
(printout t "Choose an integer greater than zero."
crlf))
(defrule name-select
(phase select-name)
=>
(printout t "What is your name? ")
(assert (name-select (read))))
(defrule good-name-choice
?phase <- (phase select-name)
?choice <- (name-select ?name&:(or (not (integerp ?name))))
=>
(retract ?phase ?choice)
(assert (name ?name)))
(defrule bad-name-choice
?phase <- (phase select-name)
?choice <- (name-select ?name&:(integerp ?name))
=>
(retract ?phase ?choice)
(assert (phase select-name))
(printout t "Please enter a name."
crlf))
(defrule person-old-female
?gender <- (gender f)
?age <- (age ?b&:(> ?b 35))
=>
(printout t "Person is female & older. This Person must go first!" crlf)
(retract ?gender)
(retract ?age)
(ask-start-again))
(defrule person-young-female
?gender <- (gender f)
?age <- (age ?age&:(<= ?age 35))
=>
(printout t "Person is female & younger. This Person must go after older males!" crlf)
(retract ?gender)
(retract ?age)
(ask-start-again))
(defrule person-old-male
?gender <- (gender m)
?age <- (age ?a&:(> ?a 35))
=>
(printout t "Person is male & older. This Person must go after older females!" crlf)
(retract ?gender)
(retract ?age)
(ask-start-again))
(defrule person-young-male
?gender <- (gender m)
?age <- (age ?age&:(<= ?age 35))
=>
(printout t "Person is male & younger. This Person must go after younger females!" crlf)
(retract ?gender)
(retract ?age)
(ask-start-again))
(defrule print-solution
=>
(printout t "Name Age Gender" crlf)
(printout t "--------------------------------------" crlf))
(defrule print-all-persons
(declare (salience -1000))
(person (name ?name) (age ?age) (gender ?gender))
=>
(printout t ?name ?age ?gender crlf))
(defrule findFirst
?p1 <- (person)
(not (and ?p2 <- (person)
(test (< (comparePerson ?p2 ?p1) 0))))
=>
(retract ?p1))
(defrule findFirst
?phase <- (phase sort-persons)
?p1 <- (person)
(not (and ?p2 <- (person)
(test (< (comparePerson ?p2 ?p1 ?*compAge* ?*compGender*) 0))))
=>
(printout t (fact-slot-value ?p1 name) " selected" crlf)
(retract ?p1))
(defglobal ?*compAge* =
(lambda (?pa ?pb)
(- (fact-slot-value ?pb age) (fact-slot-value ?pa age) )))
(defglobal ?*compGender* =
(lambda (?pa ?pb)
(- (asc (fact-slot-value ?pa gender))
(asc (fact-slot-value ?pb gender)))))
(reset)
(run)
And this is the output It does not display the output as a list of persons. I don't know what i am missing.
Is it possible to get the output like
"male 30 a
male 40 b
female 25 c
female 50 d"
What changes do I have to make to get the output as a list and sort it? thank you.

Answer 1

Assert one phase at a time:
(deffacts initial-phase (phase choose-gender))
and make sure to assert the sort phase after all input:
(deffunction ask-start-again ()
(printout t "Enter another person? (y/n) ")
(if (eq (read) y) then
(assert (phase choose-gender))
else
(assert (phase sort-persons))))
Use correct syntax for defining a template:
(deftemplate person (slot gender) (slot age) (slot name))
Asserting a person ("deffacts person") doesn't make sense.
Remove the first defrule findFirst - there is another one with the same name.
You need a rule to define a person:
(defrule define-person
?gf
(retract ?gf ?af ?nf)
(assert (person (age ?age)(name ?name)(gender ?gender)))
(ask-start-again))
Rules person-old/yound-male/female aren't useful - they just retract the data collected earlier. Also, print-all-persons doesn't help with printing the sorted facts; add a similar printout function call in rule findFirst (second version).