;;
;;  Type classes and transformer functions for input streams used by
;;  lexgen/abnf and related libraries.
;;
;;  Copyright 2010 Ivan Raikov and the Okinawa Institute of
;;  Science and Technology.
;;
;;
;; This program is free software: you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
;; published by the Free Software Foundation, either version 3 of the
;; License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; General Public License for more details.
;;
;; A full copy of the GPL license can be found at
;; <http://www.gnu.org/licenses/>.


(module input-classes

  ( 
    make-<Input> <Input>
    make-<Input+> <Input+>
    make-<EntityData> <EntityData>
    entity-data->input-port
    )

  (import scheme chicken ports)
  (require-extension typeclass)

;; input stream type class

(define-class <Input> 
  empty? 
  head 
  tail)

;; extended input stream type class

(define-class <Input+> (<Input> input) 
  find
  string->input-stream
  file->input-stream)

;; entity data type class (for MIME)

(define-class <EntityData> (<Input+> input)
  data->list list->data
  take drop append )



(define=> (entity-data->input-port <EntityData>)
  (lambda (d)
    (make-input-port
     ;; read
     (lambda () (let ((v (head d)))
		  (set! d (tail d))
		  v))
     ;; ready?
     (lambda () (and d (not (empty? d))))
     ;; close
     (lambda  () (set! d #f))
     ;; peek
     (lambda () (head d)))))


)