#lang scheme/base

;; This is a redesign of the emacs<->mzscheme communication in snot,
;; using a simpler architecture where mzscheme does most of the logic.

;; Previous design had the following problems:

;;  * repl not intelligent enough to understand the different languages used.
;;  * differences in elisp <-> scheme syntax
;;  * problematic multiplexing of data over a single channel

;; The core idea now is: keep the emacs side dumb. All significant
;; processing should be done in the scheme side, possibly also
;; providing the emacs side with code initializations.


(require
 scheme/system
 (planet "socket.ss" ("vyzo" "socket.plt" 1 2)))

 


;; Use emacsclient: it provides message atomicity.
(define (elisp str)
  (system* "/usr/bin/emacsclient"
           "-e"
           (format "~s" str)))



;; Scheme message handler. 

(define (handle in)
  (display in))

;; I get errno 71 EPROTO

;; Start server.
(define (message-server addr [handler handle])
  (let ((sock (socket PF_UNIX SOCK_STREAM 0)))
    (socket-bind sock addr)
    (socket-listen sock 5)
    (let next ()
      (let-values (((clisock cliaddr) (socket-accept sock)))
        (thread
         (lambda ()
           (let ((out (open-output-string)))
             
             (with-handlers
                 ((void (lambda (ex)
                          (printf "errr: ~a\n"
                                  (exn:socket-errno ex)))))
               (socket-recv/port sock out))
             
             (socket-close sock)
             (handle
              (get-output-string out)))))) 
      (next))))