Prevent kernel death on introspection

ipython-kernel/src/IHaskell/IPython/EasyKernel.hs

@@ -90,7 +90,7 @@ data KernelConfig m output result =
          , completion :: T.Text -> T.Text -> Int -> Maybe ([T.Text], T.Text, T.Text)
          -- | Return the information or documentation for its argument. The returned tuple consists of the
          -- name, the documentation, and the type, respectively.
-         , objectInfo :: T.Text -> Maybe (T.Text, T.Text, T.Text)
+         , inspectInfo :: T.Text -> Maybe (T.Text, T.Text, T.Text)
          -- | Execute a cell. The arguments are the contents of the cell, an IO action that will clear the
          -- current intermediate output, and an IO action that will add a new item to the intermediate
          -- output. The result consists of the actual result, the status to be sent to IPython, and the
@@ -228,25 +228,10 @@ replyTo config execCount interface req@ExecuteRequest { getCode = code } replyHe
 
 replyTo config _ _ req@CompleteRequest{} replyHeader =
   -- TODO: FIX
-  error "Unimplemented in IPython 3.0"
+  error "Completion: Unimplemented for IPython 3.0"
 
-replyTo config _ _ ObjectInfoRequest { objectName = obj } replyHeader =
-  return $
-    case objectInfo config obj of
-      Just (name, docs, ty) -> ObjectInfoReply
-        { header = replyHeader
-        , objectName = obj
-        , objectFound = True
-        , objectTypeString = ty
-        , objectDocString = docs
-        }
-      Nothing -> ObjectInfoReply
-        { header = replyHeader
-        , objectName = obj
-        , objectFound = False
-        , objectTypeString = ""
-        , objectDocString = ""
-        }
+replyTo _ _ _ InspectRequest{} _ = do
+  error $ "Inspection: Unimplemented for IPython 3.0"
 
 replyTo _ _ _ msg _ = do
   liftIO $ putStrLn "Unknown message: "

ipython-kernel/src/IHaskell/IPython/Message/Parser.hs

@@ -74,7 +74,7 @@ parser :: MessageType            -- ^ The message type being parsed.
 parser KernelInfoRequestMessage = kernelInfoRequestParser
 parser ExecuteRequestMessage = executeRequestParser
 parser CompleteRequestMessage = completeRequestParser
-parser ObjectInfoRequestMessage = objectInfoRequestParser
+parser InspectRequestMessage = inspectRequestParser
 parser ShutdownRequestMessage = shutdownRequestParser
 parser InputReplyMessage = inputReplyParser
 parser CommOpenMessage = commOpenParser
@@ -139,11 +139,12 @@ completeRequestParser = requestParser $ \obj -> do
   pos <- obj .: "cursor_pos"
   return $ CompleteRequest noHeader code pos
 
-objectInfoRequestParser :: LByteString -> Message
-objectInfoRequestParser = requestParser $ \obj -> do
-  oname <- obj .: "oname"
+inspectRequestParser :: LByteString -> Message
+inspectRequestParser = requestParser $ \obj -> do
+  code <- obj .: "code"
+  pos <- obj .: "cursor_pos"
   dlevel <- obj .: "detail_level"
-  return $ ObjectInfoRequest noHeader oname dlevel
+  return $ InspectRequest noHeader code pos dlevel
 
 shutdownRequestParser :: LByteString -> Message
 shutdownRequestParser = requestParser $ \obj -> do

ipython-kernel/src/IHaskell/IPython/Message/Writer.hs

@@ -65,15 +65,13 @@ instance ToJSON Message where
                       then string "ok"
                       else "error"
       ]
-  toJSON o@ObjectInfoReply{} =
+  toJSON i@InspectReply{} =
     object
-      [ "oname" .=
-        objectName o
-      , "found" .= objectFound o
-      , "ismagic" .= False
-      , "isalias" .= False
-      , "type_name" .= objectTypeString o
-      , "docstring" .= objectDocString o
+      [ "status" .= if inspectStatus i
+                      then string "ok"
+                      else "error"
+      , "data" .= object (map displayDataToJson . inspectData $ i)
+      , "metadata" .= object []
       ]
 
   toJSON ShutdownReply { restartPending = restart } =

ipython-kernel/src/IHaskell/IPython/Types.hs

@@ -176,8 +176,8 @@ data MessageType = KernelInfoReplyMessage
                  | InputMessage
                  | CompleteRequestMessage
                  | CompleteReplyMessage
-                 | ObjectInfoRequestMessage
-                 | ObjectInfoReplyMessage
+                 | InspectRequestMessage
+                 | InspectReplyMessage
                  | ShutdownRequestMessage
                  | ShutdownReplyMessage
                  | ClearOutputMessage
@@ -202,8 +202,8 @@ showMessageType OutputMessage = "pyout"
 showMessageType InputMessage = "pyin"
 showMessageType CompleteRequestMessage = "complete_request"
 showMessageType CompleteReplyMessage = "complete_reply"
-showMessageType ObjectInfoRequestMessage = "object_info_request"
-showMessageType ObjectInfoReplyMessage = "object_info_reply"
+showMessageType InspectRequestMessage = "inspect_request"
+showMessageType InspectReplyMessage = "inspect_reply"
 showMessageType ShutdownRequestMessage = "shutdown_request"
 showMessageType ShutdownReplyMessage = "shutdown_reply"
 showMessageType ClearOutputMessage = "clear_output"
@@ -229,8 +229,8 @@ instance FromJSON MessageType where
       "pyin"                -> return InputMessage
       "complete_request"    -> return CompleteRequestMessage
       "complete_reply"      -> return CompleteReplyMessage
-      "object_info_request" -> return ObjectInfoRequestMessage
-      "object_info_reply"   -> return ObjectInfoReplyMessage
+      "inspect_request"     -> return InspectRequestMessage
+      "inspect_reply"       -> return InspectReplyMessage
       "shutdown_request"    -> return ShutdownRequestMessage
       "shutdown_reply"      -> return ShutdownReplyMessage
       "clear_output"        -> return ClearOutputMessage
@@ -326,20 +326,22 @@ data Message =
                  , completionStatus :: Bool
                  }
              |
-               ObjectInfoRequest
+               InspectRequest
                  { header :: MessageHeader
-                 -- | Name of object being searched for.
-                 , objectName :: Text
+                 -- | The code context in which introspection is requested
+                 , inspectCode :: Text
+                 -- | Position of the cursor in unicode characters. json field @cursor_pos@
+                 , inspectCursorPos :: Int
                  -- | Level of detail desired (defaults to 0). 0 is equivalent to foo?, 1 is equivalent to foo??.
                  , detailLevel :: Int
                  }
              |
-               ObjectInfoReply
+               InspectReply
                  { header :: MessageHeader
-                 , objectName :: Text           -- ^ Name of object which was searched for.
-                 , objectFound :: Bool          -- ^ Whether the object was found.
-                 , objectTypeString :: Text     -- ^ Object type.
-                 , objectDocString :: Text
+                 -- | whether the request succeeded or failed
+                 , inspectStatus :: Bool
+                 -- | @inspectData@ can be empty if nothing is found
+                 , inspectData :: [DisplayData]
                  }
              |
                ShutdownRequest
@@ -422,7 +424,7 @@ replyType :: MessageType -> Maybe MessageType
 replyType KernelInfoRequestMessage = Just KernelInfoReplyMessage
 replyType ExecuteRequestMessage = Just ExecuteReplyMessage
 replyType CompleteRequestMessage = Just CompleteReplyMessage
-replyType ObjectInfoRequestMessage = Just ObjectInfoReplyMessage
+replyType InspectRequestMessage = Just InspectReplyMessage
 replyType ShutdownRequestMessage = Just ShutdownReplyMessage
 replyType HistoryRequestMessage = Just HistoryReplyMessage
 replyType _ = Nothing

src/Main.hs

@@ -19,6 +19,7 @@ import           Text.Printf
 import           System.Posix.Signals
 import qualified Data.Map as Map
 import           Data.String.Here (hereFile)
+import qualified Data.Text as T
 
 -- IHaskell imports.
 import           IHaskell.Convert (convert)
@@ -334,17 +335,10 @@ replyTo _ req@CompleteRequest{} replyHeader state = do
       reply = CompleteReply replyHeader (map pack completions) start end Map.empty True
   return (state, reply)
 
--- Reply to the object_info_request message. Given an object name, return the associated type
--- calculated by GHC.
-replyTo _ ObjectInfoRequest { objectName = oname } replyHeader state = do
-  docs <- pack <$> info (unpack oname)
-  let reply = ObjectInfoReply
-        { header = replyHeader
-        , objectName = oname
-        , objectFound = strip docs /= ""
-        , objectTypeString = docs
-        , objectDocString = docs
-        }
+-- TODO: Implement inspect_reply
+replyTo _ InspectRequest{} replyHeader state = do
+  -- FIXME
+  let reply = InspectReply { header = replyHeader, inspectStatus = False, inspectData = [] }
   return (state, reply)
 
 -- TODO: Implement history_reply.