More consistent naming (event -> message, etc)

simple-udp-service.rkt

@@ -8,7 +8,7 @@
 (require "dump-bytes.rkt")
 
 (provide (struct-out udp-packet)
-	 event-handlers
+	 message-handlers
 	 start-udp-service)
 
 ;; A UdpPacket is a (udp-packet Bytes String Uint16), and represents
@@ -17,12 +17,12 @@
 ;; be sent.
 (struct udp-packet (body host port) #:prefab)
 
-;; TODO: Should parse-packet be permitted to examine (or possibly
+;; TODO: Should packet->message be permitted to examine (or possibly
 ;; even transform!) the ServerState?
 
 ;; A Handler is a Message ServerState -> ListOf<Message> ServerState.
 
-(define-syntax event-handlers
+(define-syntax message-handlers
   (syntax-rules ()
     ((_ old-state-var (pattern body ...) ...)
      (list (cons (match-lambda (pattern #t) (_ #f))
@@ -34,48 +34,48 @@
 ;; Starts a generic request/reply UDP server on the given port.
 (define (start-udp-service
 	 port-number ;; Uint16
-	 parse-packet ;; UdpPacket -> Message
-	 ;--------------------------------------------------
-	 unparse-packet? ;; Message -> Boolean
-	 unparse-packet ;; Message -> UdpPacket
-	 ;--------------------------------------------------
-	 event-handlers ;; ListOf<Pair<Message -> Boolean, Handler>>
+	 packet->message ;; UdpPacket -> Message
+	 ;;--------------------------------------------------
+	 outbound-message? ;; Message -> Boolean
+	 message->packet ;; Message -> UdpPacket
+	 ;;--------------------------------------------------
+	 message-handlers ;; ListOf<Pair<Message -> Boolean, Handler>>
 	 default-handler ;; Handler
 	 initial-state ;; ServerState
 	 #:packet-size-limit
-	   [packet-size-limit 65536])
+	 [packet-size-limit 65536])
   (define s (udp-open-socket #f #f)) ;; the server socket
   (udp-bind! s #f port-number) ;; bind it to the port we were given
 
-  (set! event-handlers ;; TEMPORARY while I figure out I/O
-	(cons (cons unparse-packet?
-		    (lambda (event state)
-		      (define p (unparse-packet event))
+  (set! message-handlers ;; TEMPORARY while I figure out I/O
+	(cons (cons outbound-message?
+		    (lambda (message state)
+		      (define p (message->packet message))
 		      (match-define (udp-packet body host port) p)
 		      (printf "<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<~n~v~n" body)
 		      (dump-bytes! body (bytes-length body))
 		      (flush-output)
 		      (udp-send-to s host port body)
 		      (values '() state)))
-	      event-handlers))
+	      message-handlers))
 
-  (define (dispatch-events events next-events-rev old-state)
-    (if (null? events)
-	(check-for-io (reverse next-events-rev) old-state)
-	(let ((event (car events)))
-	  (define-values (new-events new-state)
-	    (let search ((handlers event-handlers))
+  (define (dispatch-messages messages next-messages-rev old-state)
+    (if (null? messages)
+	(check-for-io (reverse next-messages-rev) old-state)
+	(let ((message (car messages)))
+	  (define-values (new-messages new-state)
+	    (let search ((handlers message-handlers))
 	      (cond
-	       [(null? handlers) (default-handler event old-state)]
-	       [((caar handlers) event) ((cdar handlers) event old-state)]
+	       [(null? handlers) (default-handler message old-state)]
+	       [((caar handlers) message) ((cdar handlers) message old-state)]
 	       [else (search (cdr handlers))])))
-	  (dispatch-events (cdr events)
-			   (append-reverse new-events next-events-rev)
-			   new-state))))
+	  (dispatch-messages (cdr messages)
+			     (append-reverse new-messages next-messages-rev)
+			     new-state))))
 
-  (define (check-for-io pending-events old-state)
+  (define (check-for-io pending-messages old-state)
     (define buffer (make-bytes packet-size-limit))
-    (define new-events
+    (define new-messages
       (sync (handle-evt (udp-receive!-evt s buffer)
 			(match-lambda
 			 [(list packet-length source-hostname source-port)
@@ -86,12 +86,12 @@
 
 			  (define packet-and-source
 			    (udp-packet packet source-hostname source-port))
-			  (define event (parse-packet packet-and-source))
-			  (list event)]))
-	    (if (null? pending-events)
+			  (define message (packet->message packet-and-source))
+			  (list message)]))
+	    (if (null? pending-messages)
 		never-evt ;; Nothing waiting to be done, don't wake up until sth external arrives
 		(handle-evt (system-idle-evt)
 			    (lambda (dummy) '())))))
-    (dispatch-events (append new-events pending-events) '() old-state))
+    (dispatch-messages (append new-messages pending-messages) '() old-state))
 
   (check-for-io '() initial-state))

simplified-driver.rkt

@@ -72,21 +72,21 @@
 
   (start-udp-service
    port-number
-   parse-dns-event
+   udp-packet->dns-message
    dns-reply?
-   unparse-dns-event
-   (event-handlers old-state
-		   [(? bad-dns-packet? p)
-		    (pretty-print p)
-		    (values '() old-state)]
-		   [(? dns-request? r)
-		    (values (handle-request soa-rr zone r) old-state)])
+   dns-reply->udp-packet
+   (message-handlers old-state
+		     [(? bad-dns-packet? p)
+		      (pretty-print p)
+		      (values '() old-state)]
+		     [(? dns-request? r)
+		      (values (handle-request soa-rr zone r) old-state)])
    (lambda (unhandled state)
      (error 'dns-server "Unhandled packet ~v" unhandled))
    #f
    #:packet-size-limit 512))
 
-(define (parse-dns-event packet)
+(define (udp-packet->dns-message packet)
   (match-define (udp-packet body host port) packet)
   (with-handlers ((exn? (lambda (e) (bad-dns-packet body host port 'unparseable))))
     (define message (packet->dns-message body))
@@ -94,8 +94,8 @@
       ((request) (dns-request message host port))
       ((response) (bad-dns-packet message host port 'unexpected-dns-response)))))
 
-(define (unparse-dns-event event)
-  (match-define (dns-reply message host port) event)
+(define (dns-reply->udp-packet r)
+  (match-define (dns-reply message host port) r)
   (udp-packet (dns-message->packet message) host port))
 
 (define (handle-request soa-rr zone request)