run a state machine

consume an input to get an output and a new machine

src/CRM/BaseMachine.hs

@@ -116,3 +116,24 @@ identity =
     { initialState = InitialState STuple0
     , action = ActionResult
     }
+
+-- ** Run a machine
+
+-- | Given an `input`, run the machine to get an output and a new version of
+-- the machine
+runBaseMachine
+  :: BaseMachine topology input output
+  -> input
+  -> (output, BaseMachine topology input output)
+runBaseMachine (BaseMachine (InitialState initialState) action) input =
+  let
+    actionResult = action initialState input
+   in
+    case actionResult of
+      (ActionResult finalState output) ->
+        ( output
+        , BaseMachine
+            { initialState = InitialState finalState
+            , action = action
+            }
+        )

src/CRM/StateMachine.hs

@@ -67,3 +67,16 @@ instance Choice StateMachine where
   right' :: StateMachine a b -> StateMachine (Either c a) (Either c b)
   right' (Basic baseMachine) = Basic $ right' baseMachine
   right' (Compose machine1 machine2) = Compose (right' machine1) (right' machine2)
+
+-- * Run a state machine
+
+-- | Given an `input`, run the machine to get an output and a new version of
+-- the machine
+run :: StateMachine a b -> a -> (b, StateMachine a b)
+run (Basic baseMachine) a = Basic <$> runBaseMachine baseMachine a
+run (Compose machine1 machine2) a =
+  let
+    (output1, machine1') = run machine1 a
+    (output2, machine2') = run machine2 output1
+   in
+    (output2, Compose machine1' machine2')