CODEWITHSUNDEEP
clips
Pewis
Pewis

Reputation: 67

Clips Expert System

I'm trying to create an expert system that decides whether or not you can buy a house. I want to know how to word a rule that allows the person to buy a house if they're over a certain age. For Example, if you type in that you're over 40 years old the system would come back and tell you that you're not allowed to buy a home. I have tried this code below but it doesn't work

(defrule age-over-forty
    (student yes)
    (income low)
    (credit excellent)
    (age 40>)
    =>
    (printout t "You can not buy a house" crlf))

EDIT: What I mean by "it doesn't work" ; When I run it, you type in a age, lets just say I typed in 46. It would add it to the facts but it is supposed to print out "You can not buy a house" so it doesn't satisfy the (age 40>) part of the code.

Upvotes: 1

Views: 826

Answers (1)

Gary Riley
Gary Riley

Reputation: 10757

Use the predicate constraint (section 5.4.1.5 of the CLIPS 6.3 Basic Programming Guide) or alternatively the test conditional element to perform a numeric comparison.

         CLIPS (6.31 6/12/19)
CLIPS> 
(defrule age-over-forty
   (student yes)
   (income low)
   (credit excellent)
   (age ?age&:(> ?age 40))
   =>
   (printout t "You can not buy a house" crlf))
CLIPS> 
(assert (student yes)
        (income low)
        (credit excellent)
        (age 46))
<Fact-4>
CLIPS> (agenda)
0      age-over-forty: f-1,f-2,f-3,f-4
For a total of 1 activation.
CLIPS> (run)
You can not buy a house
CLIPS>

Upvotes: 1

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