Re: [newbie] I need a function for read user input.

B. Pym wrote:

B. Pym wrote:
 

Gareth McCaughan wrote:
 

    (loop for word = (read input nil) while word collect word)
 
which even the strictest LOOP-hater would have to agree
is clearer.

 
It's shorter in Gauche Scheme:
 
(use gauche.generator)
 
(generator->list (cut  read input))
 
 
Another way:
 
(use srfi-42) ; list-ec
 
(list-ec (:port word input) word)

 
Using the old-fashioned and primitive "do":
 
(do ((r () (cons x r))
     (x 0 (read)))
  ((eof-object? x) (cdr (reverse r))))

Using a slightly enhanced do:

(call-with-input-file "data.bak"
  (lambda(input)
    (do. ((word (read input) <>)
          (r () (cons word r)))
      ((? word) @ r))))

It's not too much longer than the LOOP:

(loop for word = (read input nil) while word collect word)
(do. ((word (read input) <>) (r () (cons word r))) ((? word) @ r))


Explanation:

  (call-with-input-file "data.bak"
    (lambda(input)
      (do. ((word (read input) <>)

The "<>" means repeat the preceding expression.

            (r () (cons word r)))
        ((? word) @ r))))

The "?" means test word to see if it is an empty list
or the eof-object.

If the value being returned is preceded by "@", then
it is reversed.


Another example:

(do. ((r () (cons (pop! xs) r))
      (xs '(a b c)))
  ((? xs) @ r))

  ===>
(a b c)