1 files changed, 50 insertions, 0 deletions
diff --git a/stdlib/source/library/lux/control/concurrency/behavioral.lux b/stdlib/source/library/lux/control/concurrency/behavioral.lux
new file mode 100644
index 000000000..1865558aa
--- /dev/null
+++ b/stdlib/source/library/lux/control/concurrency/behavioral.lux
@@ -0,0 +1,50 @@
+(.require
+ [library
+  [lux (.except)]]
+ [//
+  ["[0]" async (.only Async) (.use "[1]#[0]" monad)]
+  ["[0]" frp (.only Channel)]])
+
+(def <Event>
+  (template (_ Constructor data)
+    [[(Constructor data) data]]))
+
+(type .public (Constructor data)
+  (-> data (<Event> Constructor data)))
+
+(type .public Event
+  (Ex (_ data)
+    (<Event> Constructor data)))
+
+(def .public (event constructor)
+  (All (_ data)
+    (-> (-> data data)
+        (Constructor data)))
+  (exec
+    [] ... This was added to avoid having auto-currying to fuse the "event" and "self" functions.
+    ... Otherwise, the "same?" comparison done later would fail.
+    (function (self data)
+      [self (constructor data)])))
+
+(def .public (event? expected it)
+  (All (_ data)
+    (-> (Constructor data) Event
+        (Maybe data)))
+  (let [[actual data] it]
+    (if (same? expected actual)
+      {.#Some (as_expected data)}
+      {.#None})))
+
+(def .public (scenario events expected initial behavior)
+  (All (_ state data)
+    (-> (Channel Event) (Constructor data) state (-> data state (Async state))
+        (Async state)))
+  (frp.mix (function (_ event state)
+             (when (event? expected event)
+               {.#Some data}
+               (behavior data state)
+               
+               {.#None}
+               (async#in state)))
+           initial
+           events))