#| Common code between the client and server

 WARNING: requests cannot contain invalid read characters.
e.g. don't try to send procedure objects or other objects that
STk prints as #[...]

Example misuse:
  (send-request (make-request 'dummy1 'dummy2 'send-msg car))
|#


;; REQUEST ADT
(define (make-request src dst action data)
  (list src dst action data))

(define (request-src req) (list-ref req 0))
(define (request-dst req) (list-ref req 1))
(define (request-action req) (list-ref req 2))
(define (request-data req) (list-ref req 3))


;; SEND/GET Request from ports
(define (send-request req write-port)
  (if (and (not (null? write-port)) (not (port-closed? write-port)))
      (begin (format write-port "~S" req)
	     (flush write-port)
	     'okay)
      (begin (format #t "Could not send request to port.~%")
	     #f)))


(define (get-request read-port)
  (if (and (not (null? read-port)) (not (port-closed? read-port)))
      (let ((raw-msg (read read-port)))
	(if (eof-object? raw-msg)
	    (begin (format #t "Could not get request from port (EOF)~%")
		   #f)
	    raw-msg))
      (begin (format #t "Could not get request from port (EOF)~%")
	     #f)))