c3 41-43

seckcoder · seckcoder · commit 8455126cb04e · 2013-08-03T00:53:38.000+08:00
diff --git a/src/c3_41.scm b/src/c3_41.scm
@@ -0,0 +1,2 @@
+; another stupid question.
+; The chapter is awful
diff --git a/src/c3_42.scm b/src/c3_42.scm
@@ -0,0 +1,2 @@
+; this seems like an implementation dependent problem
+; what will happend may depend on the implementation of serializer.
diff --git a/src/c3_43.scm b/src/c3_43.scm
@@ -0,0 +1 @@
+; My answer is on http://sicp.readthedocs.org/en/latest/chp3/43.html
diff --git a/src/lib/concurrency.scm b/src/lib/concurrency.scm
@@ -5,4 +5,14 @@
 
   (define (parallel-execute . args)
     (for-each fork-thread args))
+
+  (define (make-serializer)
+    (let ((mutex (make-mutex)))
+      (lambda (p)
+        (define (serialized-p . args)
+          (mutex 'acquire)
+          (let ((val (apply p args)))
+            (mutex 'release)
+            val))
+        serialized-p)))
   )

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+; this seems like an implementation dependent problem`
	`2`	`+; what will happend may depend on the implementation of serializer.`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+; My answer is on http://sicp.readthedocs.org/en/latest/chp3/43.html`