From Newsgroup: comp.lang.lisp

Frank Buss wrote:

For example, take a look at the telegram problem:

http://en.wikipedia.org/wiki/Flow-based_programming#.22Telegram_Problem.22

Your task is to write a function, which reformats a text for a specified
line width, e.g. this call:

(telegram "
Du bist am Ende- was du bist. Setz dir Pern++cken auf von Millionen Locken, Setz deinen Fun++ auf ellenhohe Socken, Du bleibst doch immer, was du bist." 30)

outputs these lines:

Du bist am Ende- was du bist.
Setz dir Pern++cken auf von
Millionen Locken, Setz deinen
Fun++ auf ellenhohe Socken, Du
bleibst doch immer, was du
bist.

Gauche Scheme

(use srfi-13) ;; string-tokenize
(use srfi-197) ;; chain

(define (string->words str)
(string-tokenize str))

(define (words->lines words width)
(let ((output '())
(tmp (if (null? words) "" (pop! words))))
(while (pair? words)
(let ((word (pop! words)))
(if (< (+ (string-length word) (string-length tmp)) width)
(set! tmp (string-append tmp " " word))
(begin
(push! output tmp)
(set! tmp word)))))
(when (not (equal? "" tmp)) (push! output tmp))
(reverse output)))

(define (telegram str width)
(chain
str
(string->words _)
(words->lines _ width)))

(for-each
print
(telegram "
Du bist am Ende- was du bist. Setz dir Pern++cken auf
von Millionen Locken,
Setz deinen Fun++ auf ellenhohe Socken, Du bleibst doch
immer, was du bist."
30))

Du bist am Ende- was du bist.
Setz dir Pern++cken auf von
Millionen Locken, Setz deinen
Fun++ auf ellenhohe Socken, Du
bleibst doch immer, was du
bist.
--
The good news is, it's not Lisp that sucks, but Common Lisp. --- Paul Graham --- Synchronet 3.21a-Linux NewsLink 1.2