Conform to the messaging spec

Still no visible outputs.

ihaskell-display/ihaskell-widgets/src/IHaskell/Display/Widgets/Button.hs

@@ -44,19 +44,13 @@ mkButton = do
   let b = Button uuid desc ttip dis sty
 
   -- Open a comm for this widget, and store it in the kernel state
-  widgetSendOpen b $ toJSON ButtonInitData
-
-  -- Initial state update
-  widgetSendUpdate b . toJSON . UpdateState . toJSON $ b
-
-  -- DEBUG: Try to display it too
-  widgetSendView b
+  widgetSendOpen b (toJSON ButtonInitData) (toJSON b)
 
   -- Return the button widget
   return b
 
 update :: Button -> [Pair] -> IO ()
-update b v = widgetSendUpdate b . toJSON . UpdateState . object $ v
+update b v = widgetSendUpdate b . toJSON . object $ v
 
 -- | Set the button style
 setButtonStyle :: ButtonStyle -> Button -> IO ()

main/Main.hs

@@ -294,7 +294,7 @@ replyTo interface req@ExecuteRequest { getCode = code } replyHeader state = do
               else sendOutput $ Display pager
 
       handleMessage :: KernelState -> WidgetMsg -> IO KernelState
-      handleMessage state (Open widget value) = do
+      handleMessage state (Open widget initVal stateVal) = do
         -- Check whether the widget is already present in the state
         let oldComms = openComms state
             uuid     = getCommUUID widget
@@ -305,15 +305,18 @@ replyTo interface req@ExecuteRequest { getCode = code } replyHeader state = do
 
             target   = targetName widget
 
-            communicate value = do
+            communicate val = do
               head <- dupHeader replyHeader CommDataMessage
-              writeChan (iopubChannel interface) $ CommData head uuid value
+              writeChan (iopubChannel interface) $ CommData head uuid val
 
         if present
           then return state
           else do -- Send the comm open
                   header <- dupHeader replyHeader CommOpenMessage
-                  send $ CommOpen header target uuid value
+                  send $ CommOpen header target uuid initVal
+
+                  -- Initial state update
+                  communicate . toJSON $ UpdateState stateVal
 
                   -- Send anything else the widget requires.
                   open widget communicate

src/IHaskell/Eval/Evaluate.hs

@@ -918,7 +918,7 @@ evalCommand output (Expression expr) state = do
                   uuid = getCommUUID widget
               case Map.lookup uuid oldComms of
                Nothing -> error "Unregistered widget"
-               Just w  -> do
+               Just _  -> do
                  liftIO $ widgetSendView widget
                  return evalOut
 

src/IHaskell/Eval/Widgets.hs

@@ -41,8 +41,9 @@ widgetSend :: IHaskellWidget a
               -> a -> Value -> IO ()
 widgetSend msgType widget value = queue $ msgType (Widget widget) value
 
-widgetSendOpen :: IHaskellWidget a => a -> Value -> IO ()
-widgetSendOpen = widgetSend Open
+widgetSendOpen :: IHaskellWidget a => a -> Value -> Value -> IO ()
+widgetSendOpen widget initVal stateVal =
+  queue $ Open (Widget widget) initVal stateVal
 
 widgetSendUpdate :: IHaskellWidget a => a -> Value -> IO ()
 widgetSendUpdate = widgetSend Update

src/IHaskell/Types.hs

@@ -182,10 +182,11 @@ data LintStatus = LintOn
                 | LintOff
   deriving (Eq, Show)
 
-data WidgetMsg = Open Widget Value
+data WidgetMsg = Open Widget Value Value
                  -- ^ Cause the interpreter to open a new comm, and
                  -- register the associated widget in the
-                 -- kernelState.
+                 -- kernelState. Also sends a Value with comm_open,
+                 -- and then sends an initial state update Value.
                | Update Widget Value
                  -- ^ Cause the interpreter to send a comm_msg
                  -- containing a state update for the widget.