literate-programming/example.org

(define member? (λ (a lat) (cond [(null? lat) #f] [else (or (eq? a (car lat)) (member? a (cdr lat)))])))

Lets test it:

<>

(display (simple-format #f "(member? 1 '(3 2 1)) -> ~a\n" (member? 1 '(3 2 1))))

(display (simple-format #f "(member? 1 '(3 2 4)) -> ~a\n" (member? 1 '(3 2 4))))