;;;;A sample source file
;;The fak function, n!
   
(define (fak n) (if (= n 0) ; 1 ; (* n (fak (- n 1))) ; ) ) ;;Return the list of the first n elements of lst. ;; If n < (length lst) just return lst
(define (list-prefix lst n) (if (< (length lst) n) lst (list-prefix-1 lst n)))
(define (list-prefix-1 lst n) (if (= n 0) '() (cons (car lst) (list-prefix-1 (cdr lst) (- n 1)))))