; Numara cate mere sunt in sacosa

(deffacts grup1

  (sacosa mar1 mar2 mar3 mar4)
  (contor 0)
)

(defrule numara-mere
; conditii  
  ?idx <- (sacosa $?beg ?x $?rest)
  ?ctr <- (contor ?y)
  =>
; actiuni
  (retract ?idx ?ctr)
  (assert (sacosa $?beg $?rest)
          (contor =(+ ?y 1)))
)