From 51ab2921c2f7102004b8edce5ae0f1e10b126c85 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonygarnockjones@gmail.com>
Date: Thu, 28 Sep 2017 16:26:01 +0100
Subject: [PATCH] New examples

---
 .../syndicate/examples/actor/mutable-cell.rkt | 39 +++++++++++++++++++
 .../examples/actor/simple-cross-layer.rkt     | 13 ++++---
 2 files changed, 46 insertions(+), 6 deletions(-)
 create mode 100644 racket/syndicate/examples/actor/mutable-cell.rkt

diff --git a/racket/syndicate/examples/actor/mutable-cell.rkt b/racket/syndicate/examples/actor/mutable-cell.rkt
new file mode 100644
index 0000000..9675487
--- /dev/null
+++ b/racket/syndicate/examples/actor/mutable-cell.rkt
@@ -0,0 +1,39 @@
+#lang syndicate
+
+(assertion-struct cell (id value))
+(message-struct create-cell (id value))
+(message-struct update-cell (id value))
+(message-struct delete-cell (id))
+
+(define (spawn-cell initial-value)
+  (define id (gensym 'cell))
+  (send! (create-cell id initial-value))
+  id)
+
+(spawn #:name 'cell-factory
+  (on (message (create-cell $id $initial-value))
+      (spawn #:name (list 'cell id)
+        (field [value initial-value])
+        (assert (cell id (value)))
+        (on (message (update-cell id $new-value)) (value new-value))
+        (stop-when (message (delete-cell id))))))
+
+(define (spawn-cell-monitor id)
+  (spawn #:name (list 'cell-monitor id)
+    (on (asserted (cell id $value))
+        (printf "Cell ~a updated to: ~a\n" id value))
+    (on (retracted (cell id _))
+        (printf "Cell ~a deleted\n" id))))
+
+(define (read-cell id)
+  (flush!) ;; this is important! else previous writes remain buffered after the first read
+  (react/suspend (k)
+                 (stop-when (asserted (cell id $value)) (k value))))
+
+(spawn* #:name 'main-actor
+        (define id (spawn-cell 123))
+        (spawn-cell-monitor id)
+        (send! (update-cell id (+ (read-cell id) 1)))
+        (send! (update-cell id (+ (read-cell id) 1)))
+        (send! (update-cell id (+ (read-cell id) 1)))
+        (send! (delete-cell id)))
diff --git a/racket/syndicate/examples/actor/simple-cross-layer.rkt b/racket/syndicate/examples/actor/simple-cross-layer.rkt
index 402b50f..4399bd2 100644
--- a/racket/syndicate/examples/actor/simple-cross-layer.rkt
+++ b/racket/syndicate/examples/actor/simple-cross-layer.rkt
@@ -2,10 +2,11 @@
 
 (assertion-struct greeting (text))
 
-(spawn (assert (greeting "Hello from an outer dataspace actor!")))
-(spawn (on (asserted (greeting $t))
-           (printf "Outer dataspace: ~a\n" t)))
+(spawn #:name "A" (assert (greeting "Hi from outer space!")))
+(spawn #:name "B" (on (asserted (greeting $t))
+                      (printf "Outer dataspace: ~a\n" t)))
 
-(dataspace (spawn (assert (outbound (greeting "Hello from an inner dataspace actor!"))))
-           (spawn (on (asserted (inbound (greeting $t)))
-                      (printf "Inner dataspace: ~a\n" t))))
+(dataspace #:name "C"
+  (spawn #:name "D" (assert (outbound (greeting "Hi from inner!"))))
+  (spawn #:name "E" (on (asserted (inbound (greeting $t)))
+                        (printf "Inner dataspace: ~a\n" t))))