(define (find? ?target lst)
  (cond ((null? lst) #f)
        ((eq? ?target (car lst)) 0)
        ((not (eq? (find? ?target (cdr lst)) #f))
         (+ 1 (find? ?target (cdr lst))))
        (else #f)))

(find? 4 (list 1 2 3 4 5 6))
(find? 1 (list 1 2 3 4 5 6))

(find? 4 (list 1 2 3))

(define name 'Joe)

(find? name (list 1 4 6 'Joe' 5 4/3 3+7i))