규칙은 질의 하나를 더 작은 목표들의 수열로 바꾼다.

(begin
  (define facts
    '((parent ada ben)
      (parent ben cy)
      (parent ada dia)
      (parent dia eli)))
  (define query '(parent ada (var child)))
  (define (match-assertion query assertion)
    (if (and (eq? (car query) (car assertion))
             (eq? (cadr query) (cadr assertion)))
        (list (cons (cadr (caddr query)) (caddr assertion)))
        #f))
  (define (scan-assertions remaining answers)
    (if (null? remaining)
        (reverse answers)
        (let ((frame (match-assertion query (car remaining))))
          (scan-assertions (cdr remaining)
                           (if frame (cons frame answers) answers)))))
  (scan-assertions facts '()))