;; this is map
(define (map1 f l)
  (if (null? l)
      ()
      (cons (f (car l))
            (map1 f (cdr l)))))

;; this version uses list instead of cons
;; (it doesn't work right)
(define (map1-bad f l)
  (if (null? l)
      ()
      (list (f (car l))
            (map1 f (cdr l)))))


Welcome to DrScheme, version 205.
Language: Standard (R5RS).
> (map1 abs '(3 -7 9 1 -17))
(3 7 9 1 17)

> (map1-bad abs '(3 -7 9 1 -17))
(3 (7 (9 (1 (17 ())))))

> (cons 3 '(5))
(3 5)
> (list 3 '(5))
(3 (5))

;; built-in scheme takes multiple lists
> (map + '(1 5 7) '(3 4 5))
(4 9 12)

;; you need to pass a function that takes the right
;; number of args to map -- we see that abs doesn't take
;; two args, and what follows if we pass it to map
;; with two lists...
> (abs 3 5)
. abs: expects 1 argument, given 2: 3 5
> (map abs '(1 5 7) '(3 4 5))
. map: arity mismatch for abs: expects 1 argument, given 2