September Morn Update

Task/Synchronous-concurrency/Racket/synchronous-concurrency-1.rkt

@@ -0,0 +1,17 @@
+(define (reader)
+  (for ([line (in-lines (open-input-file "input.txt"))])
+    (thread-send printer-thread line))
+  (thread-send printer-thread eof)
+  (printf "Number of lines: ~a\n" (thread-receive)))
+
+(define (printer)
+  (thread-send reader-thread
+               (for/sum ([line (in-producer thread-receive eof)])
+                 (displayln line)
+                 1)))
+
+(define printer-thread (thread printer))
+(define reader-thread  (thread reader))
+
+(for-each thread-wait
+          (list printer-thread reader-thread))

Task/Synchronous-concurrency/Racket/synchronous-concurrency-2.rkt

@@ -0,0 +1,19 @@
+(define (reader out-ch result-ch)
+  (for ([line (in-lines (open-input-file "input.txt"))])
+    (channel-put out-ch line))
+  (channel-put out-ch eof)
+  (printf "Number of lines: ~a\n" (channel-get result-ch)))
+
+(define (printer in-ch result-ch)
+  (channel-put result-ch
+               (for/sum ([line (in-producer channel-get eof in-ch)])
+                 (displayln line)
+                 1)))
+
+(define lines-ch (make-channel))
+(define result-ch (make-channel))
+(define printer-thread (thread (lambda () (printer lines-ch result-ch))))
+(define reader-thread  (thread (lambda () (reader lines-ch result-ch))))
+
+(for-each thread-wait
+          (list printer-thread reader-thread))

Task/Synchronous-concurrency/Racket/synchronous-concurrency.rkt

@@ -1,29 +0,0 @@
-(define reader->printer-channel (make-channel))
-(define printer->reader-channel (make-channel))
-
-(define (sync-line-counter filename)
-  (define (reader)
-    (define file-port (open-input-file filename))
-    (let loop ([line (read-line file-port)])
-      (when (not (eof-object? line))
-        (begin
-          (channel-put reader->printer-channel line)
-          (loop (read-line file-port)))))
-    (channel-put reader->printer-channel eof)
-    (let ([num-lines (channel-get printer->reader-channel)])
-      (printf "Number of lines printed = ~a~%" num-lines)))
-
-  (define (printer)
-    (define count 0)
-    (let loop ([line (channel-get reader->printer-channel)])
-      (when (not (eof-object? line))
-        (begin
-          (printf "~a~%" line)
-          (set! count (add1 count))
-          (loop (channel-get reader->printer-channel)))))
-    (channel-put printer->reader-channel count))
-
-  (thread reader)
-  (thread printer))
-
-(sync-line-counter "input.txt")