Data commit

Task/Synchronous-concurrency/EchoLisp/synchronous-concurrency.l

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+(require 'sequences)
+(require 'tasks)
+
+;; inter-tasks message : (op-code . data)
+(define (is-message? op message)
+	(and message (equal? op (first message))))
+
+;; reader task
+(define (reader infile )
+	(wait S)
+	(define message (semaphore-pop S))
+	(when (is-message? 'count message ) (writeln 'reader-> message) (task-stop-all))
+	
+	(if (first infile) ;; not EOF
+	(set! message (cons 'write (next infile)))
+	(set! message (list 'reader-count-please)))
+	
+	(semaphore-push S message)
+	(signal S)
+	infile)
+	
+(define (writer count)
+	(wait S)
+	(define message (semaphore-pop S))
+	(when  (is-message? 'write message )
+			(writeln (rest message))
+			(set! count (1+ count))
+			(set! message (cons 'ack count)))
+	
+	(when  (is-message? 'reader-count-please message )
+		 (set! message (cons 'count count)))
+	(semaphore-push S message)
+	(signal S)
+	count)