callback.scm

;;; callback hellを限定継続でなんとかしようとしたログ

;; callbackなファイルAPI
(use gauche.partcont)
(use file.util)

(define (read-dir dir callback)
  (callback (filter (compose not file-is-directory?) (directory-list dir))))

(define (read-file path callback)
  (callback (file->string path)))

;; 普通にcallbackで書く
(read-dir "./" (lambda (files) 
		(read-file (car files) (lambda (data)
                                         (display data)))))

;; shift/resetで書く
(reset 
 (display
  (shift cont1
         (reset (read-file
                 (shift cont2 
                        (read-dir "./" (compose cont2 car)))
                 cont1)))))

;; letで名前を付ける
(let [(data 
       (shift cont1
              (reset (let [(file (shift cont2
                                        (read-dir "./" (compose cont2 car))))]
                       (read-file file cont1)))))]
  (reset (display data)))

;; let*で更に書き直す
(let* [(file (shift cont1 (read-dir "./" (compose cont1 car))))
       (data (shift cont2 (reset (read-file file cont2))))]
  (reset (display data)))