(define (get-one-word start)
(let loop ((chars #null) (end start))
   (let ((char (car end)))
      (if (has? (list #\space #\newline) char)
         (values (reverse chars) (force (cdr end)))
         (loop (cons char chars) (force (cdr end)))))))

(define (get-all-words string)
(let loop ((words #null) (start (str-iter string)))
   (let* ((word next (get-one-word start)))
      (if (null? next)
         (reverse words)
         (loop (cons (runes->string word) words) next)))))

(define (get-one-line words n)
(let loop ((line #null) (words words) (i 0))
   (let*((word (car words))
         (len (string-length word)))
      (if (null? (cdr words))
         (values (reverse (cons word line)) #null)
         (if (> (+ i len) n 1)
            (values (reverse line) words)
            (loop (cons word line) (cdr words) (+ i len 1)))))))

(define (get-all-lines words n)
(let loop ((lines #null) (words words))
   (let* ((line words (get-one-line words n)))
      (if (null? words)
         (reverse (cons line lines))
         (loop (cons line lines) words)))))

(define (hyphenation width string)
(let*((words (get-all-words string))
      (lines (get-all-lines words width)))
   lines))