CODEWITHSUNDEEP
stringsyntaxcompareconditional-statementsclips
Khanit Santiprayoon
Khanit Santiprayoon

Reputation: 13

clips use string to make a compare condition

I'm very very new to Clips expert system I'm looking for what is a syntax to use for compare a text from previous rules

like this

(defrule GetGender
(declare (salience 100))
(printout t "What's your gender ? (Male/Female): ")
(bind ?response (read))
(assert (Gender (gender ?response))))

and when I get answer from above like "Male" I want the rule below active.

(defrule GetShirt
(declare (salience 99))
(Gender (gender ?l))
(test (= ?l Male))
=>
(printout t "What's your shirt color ? (Blue/Black): ")
(bind ?response (read))
(assert (Shirt (shirt ?response))))

But seem (test and =) is not a syntax for string compare, and my English is not good enough, I don't even know about what "?l" in the code means

could somebody help me to fix this out please ?

Thank you.

Upvotes: 1

Views: 2306

Answers (2)

Gary Riley
Gary Riley

Reputation: 10757

Use = for comparing numbers and eq for comparing values of any type. In your GetShirt rule, the token ?l is a variable that is bound to the value of the gender slot so that it can be used in the expression (= ?l Male). When making simple comparisons to constants, it's not necessary to use the test conditional element. You can simply use the constant within the pattern:

CLIPS> 
(deftemplate response
   (slot attribute)
   (slot value))
CLIPS> 
(defrule GetGender
   =>
   (printout t "What's your gender ? (Male/Female): ")
   (bind ?response (read))
   (assert (response (attribute gender) (value ?response))))
CLIPS> 
(defrule GetShirt
   (response (attribute gender) (value Male))
   =>
   (printout t "What's your shirt color ? (Blue/Black): ")
   (bind ?response (read))
   (assert (response (attribute shirt) (value ?response))))
CLIPS> (reset)
CLIPS> (run)
What's your gender ? (Male/Female): Male
What's your shirt color ? (Blue/Black): Blue
CLIPS>

Upvotes: 1

noxdafox
noxdafox

Reputation: 15060

= is for comparing numbers.

For strings, you need to use the eq function.

In [1]: (eq "foo" "bar")
FALSE
In [2]: (eq "foo" "foo")
TRUE

Upvotes: 1

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