(define some-list '("hello" "world"))

(let loop
   ((todo some-list))
   (unless (null? todo)
      (write (string-length (car todo)))
      (newline)
      (loop (cdr todo))))

(define (string-lengths some-list)
   (unless (null? some-list)
      (write (string-length (car some-list)))
      (newline)
      (string-lengths (cdr some-list))))

(string-lengths '("hello" "world"))

(define some-list '("hello" "world"))

(for-each
  (lambda (str)
    (write (string-length str))
    (newline))
  some-list) 

;; Now let's start moving away from the imperative model

(define some-list '("hello" "world"))

(write (map string-length some-list))

;; Wasn't THAT simpler? :-)

(define (string-lengths some-list #!optional (lengths '()))
  ; some-list - the list of strings.
  ; lengths - the length of the strings we've calc'd so far : initially '().
  (if (null? somelist)
    (begin ; "base case" - we're at the end of some-list.
      (display "Got empty list: ending")
      (newline)
      (reverse lengths))
    (begin ; take the first element in the list and work out the length.
      (display (string-length (car some-list)))
      (newline)
      (string-lengths ; pass on the rest of the list and the list of lengths.
        (cdr some-list) ; the tail of some-list
        (cons - place the string-length of list list at the head of the list of lengths.
          (string-length (car some-list))
          lengths)))))