问CLIPS程序测试字符串

EN

(deftemplate star
   (slot name)
   (slot spectral)
   (slot magnitude)
   (slot distance))

(deffacts stars
   (star (name "Sirius") (spectral "A") (magnitude 1) (distance 8.8))
   (star (name "Canopus") (spectral "F") (magnitude -3) (distance 98)) 
   (star (name "Arcturus") (spectral "K") (magnitude 0) (distance 36)) 
   (star (name "Vega") (spectral "A") (magnitude 1) (distance 26)) 
   (star (name "Capella") (spectral "G") (magnitude -1) (distance 46)) 
   (star (name "Rigel") (spectral "B") (magnitude -7) (distance 880)) 
   (star (name "Procyon") (spectral "F") (magnitude 3) (distance 11)) 
   (star (name "Betelgeuse") (spectral "M") (magnitude -5) (distance 490)) 
   (star (name "Altair") (spectral "A") (magnitude 2) (distance 16)) 
   (star (name "Aldebaran") (spectral "K") (magnitude -1) (distance 68)) 
   (star (name "Spica") (spectral "B") (magnitude -3) (distance 300)) 
   (star (name "Antares") (spectral "M") (magnitude -4) (distance 250))
   (star (name "Pollux") (spectral "K") (magnitude 1) (distance 35))
   (star (name "Deneb") (spectral "A") (magnitude -7) (distance 1630)) )

(defrule start-up 
   ?i <- (initial-fact) 
   => 
   (printout t "Stars spectral class?: ") 
   (bind ?y (read)) 
   (assert (spectral ?y)) 
   (retract ?i))

(defrule P1
   ?char <- (star (name ?n) (spectral ?s) (magnitude ?m) (distance ?d))
   (spectral ?y)
   (test (eq ?s ?y)
   => 
   (printout t ?n ", " ?s ", " ?m ", " ?d crlf)
   (retract ?char)
   (assert (found)))

Defining deftemplate: star
Defining deffacts: stars
Defining defrule: start-up +j+j
Defining defrule: P1
[PRNTUTIL2] Syntax Error:  Check appropriate syntax for test conditional element.

ERROR:
(defrule MAIN::P1
   ?char <- (star (name ?n) (spectral ?s) (magnitude ?m) (distance ?d))
   (spectral ?y)
   (test (eq ?s ?y)=>
FALSE
CLIPS>