Misunderstood the schema

.gitignore

@@ -26,4 +26,5 @@ stack.yaml.lock
 result
 default.nix
 dist-*/
-cabal.project.local
\ No newline at end of file
+cabal.project.local
+cabal.config
\ No newline at end of file

ihaskell-display/ihaskell-widgets/MsgSpec.md

@@ -39,9 +39,12 @@ the kernel.
 ## Displaying widgets
 
 The creation of a widget does not display it. To display a widget, the kernel sends a display
-message to the frontend on the widget's iopub, with a custom mimetype instead of text/plain.
-You can also send the ViewModuleVersion in the two fields `version_major` and `verison_minor`.
-Only the `model_id` is required.
+message to the frontend on the widget's iopub, with a custom mimetype instead of text/plain. Since 5.0, all custom json metadata should be encoded as a json object, instead of as a serialized string.
+
+The `version_major` and `version_minor` fields are the version number of the schema of this specific message
+(currently in sync with the WMP version). However, only the `model_id` field is required to display the widget.
+
+[Source](https://github.com/jupyter-widgets/ipywidgets/issues/3220)
 
 ```json
 method = "display_data",

ihaskell-display/ihaskell-widgets/ihaskell-widgets.cabal

@@ -110,7 +110,7 @@ library
 
 					 -- The singletons package version is locked to the compiler
 					 -- so let cabal choose the right one.
-                     , singletons -any
+                     , singletons < 3.0.0
 
   -- Directories containing source files.
   hs-source-dirs:      src

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

@@ -918,16 +918,13 @@ triggerDisplay = triggerEvent DisplayHandler
 -- | Every IHaskellWidget widget has the same IHaskellDisplay instance, for this
 -- reason we need to use FlexibleContexts. The display implementation can still
 -- be overriden per widget
-instance ('S.ViewModuleVersion ∈ WidgetFields w, IHaskellWidget (IPythonWidget w)) => IHaskellDisplay (IPythonWidget w) where
+instance IHaskellWidget (IPythonWidget w) => IHaskellDisplay (IPythonWidget w) where
   display b = do
     widgetSendView b -- Keeping compatibility with classic notebook
-    (version_major,version_minor) <- versionToInteger <$> getField b ViewModuleVersion
     return $ Display [ widgetdisplay $ unpack $ decodeUtf8 $ encode $ object [
       "model_id" .= getCommUUID b, 
-      "version_major" .= version_major, 
+      "version_major" .= version_major,
       "version_minor" .= version_minor] ]
     where
-      versionToInteger :: Text -> (Int,Int)
-      versionToInteger str = toTuple (fmap (val.decimal) (splitOn "." str))
-      toTuple (x:y:_) = (x,y)
-      val (Right (v,_)) = v             
+      version_major = 2 :: Int
+      version_minor = 0 :: Int