Create rules in CLIPS to move from unknown to known person facts

Question

Assume that you are given a set of 'person' facts that are defined according to the following construct:

(deftemplate person (slot name) (slot sex) (allowed-values male female) (multislot children))

Write rules to do the following:

Create a fact of the form (unknown-person ) for each name that appears in the children multislot of a person fact but not in the name slot of any person fact (it is assumed that no two people have the same name)
For each fact of the form (unknown-person ) ask the user for the sex of the person, retract the fact and assert a new fact of the form (unknown-person ).
For each fact of the form (unknown-person ), retract the fact and create a new person fact for the person (it is assumed that the person has no children).

Your rules should do data validation to ensure that only an allowed value for is supplied by the user

Irwin Irwin · Accepted Answer · 2013-05-15T14:34:18

Define the template in CLIPS:

(deftemplate person 
    (slot name) 
    (slot sex) 
    (slot gender (allowed-values male female)) 
    (multislot children))

Start with the unknown-person creation (caveat: this may not be completely correct as it still creates a person without checking to see if they exist).

(defrule childrencataloguer "First layer of unknown person resolution"
    (person (children $?ch))
    =>
    (progn$ (?term ?ch)
        (assert (unknown-person ?term))
    ))

Deal with the caveat above

(defrule removeunknownswithpersonsalready
    (person (name ?n))
    ?up <-(unknown-person ?n)
    =>
    (retract ?up))

Now, get the gender:

(defrule getgender 
    ?up-nogen <-(unknown-person ?n)
    =>
    (retract ?up-nogen)
    (printout t crlf "Please enter male or female to indicate " ?n "'s gender" crlf )
    (assert (unknown-person ?n (read)))
)

There are other ways you can do the gender confirmation, I would have liked to use the deftemplate itself, so that the allowed-values would have fed into the validation. But I don't know how yet.

(assert (gender male))
(assert (gender female))

Now, do validation:

(defrule checkgender
    ?p <- (unknown-person ?n ?s)
    (not (gender ?s))
    =>
    (retract ?p)
    (assert (unknown-person ?n))
)

Finally, graduate from unknown

(defrule graduatefromunknown
    (declare (salience -10))
    ?up <- (unknown-person ?n ?s)
    =>
    (retract ?up)
    (assert (person (name ?n) (sex ?s)))
)

Create rules in CLIPS to move from unknown to known person facts

1 Answers