gistfile1.scm

(define (remains lst key)
  (cond ((null? lst) -1)
        ((eq? (car lst) key) (length (cdr lst)))
        (else (remains (cdr lst) key))))


(define sample-list '(World is not enough))
(remains sample-list 'World)   ;; =>  3
(remains sample-list 'is)      ;; =>  2
(remains sample-list 'enough)  ;; =>  0
(remains sample-list 'nothing) ;; => -1


;; see also http://kaitenn.blogspot.com/2010/01/scala-list.html
;;          http://d.hatena.ne.jp/yuroyoro/20100205/1265363784