Fix up complete_reply messages (#8).

The reason that aavogt's complete_reply messages were not showing up is because the "Messagin in IPython" documentation is missing a field for the complete_reply messages. There needs to be a "matched_text" field which contains the part of the line on which completions were computed. I have added that field and it seems to work now.

FYI, I figured this out because tab completion on the notebook was raising javascript errors in the browser. For future reference, this could be a useful thing to check if something in the notebook is not working.

IHaskell/Completion.hs

@@ -15,7 +15,7 @@ module IHaskell.Completion (makeCompletions) where
 import Prelude
 import Data.List
 import IHaskell.Types
-import GhcMonad(liftIO)
+import GhcMonad(liftIO, GhcMonad)
 import qualified GHC
 import Outputable (showPpr)
 import Data.Char
@@ -26,6 +26,8 @@ import Data.Aeson
 import IHaskell.Message.Writer
 import qualified Data.ByteString.Lazy as L
 
+makeCompletions
+  :: GHC.GhcMonad m => MessageHeader -> Message -> m Message
 makeCompletions replyHeader (CompleteRequest hdr code line pos) = do
 
     ns <- GHC.getRdrNamesInScope
@@ -34,8 +36,9 @@ makeCompletions replyHeader (CompleteRequest hdr code line pos) = do
     let candidate = getWordAt (toString line) pos
         opts | Just cand <- candidate = filter (cand `isPrefixOf`) $ map (showPpr fs) ns
              | otherwise = []
+        matched_text = fromString $ maybe "" id candidate
 
-    let reply = CompleteReply replyHeader (map fromString opts) line True
+    let reply = CompleteReply replyHeader (map fromString opts) matched_text line True
     liftIO (L.putStrLn $ encode $ toJSON reply)
     return reply
 

IHaskell/Message/Writer.hs

@@ -56,8 +56,9 @@ instance ToJSON Message where
                              "execution_count" .= execCount,
                              "code" .= code
                            ]
-  toJSON (CompleteReply _ m t s) = object [
+  toJSON (CompleteReply _ m mt t s) = object [
                              "matches" .= m,
+                             "matched_text" .= mt,
                              "text" .= t,
                              "status" .= if s then "ok" :: String else "error"
                            ]

IHaskell/Types.hs

@@ -200,6 +200,7 @@ data Message
   | CompleteReply {
      header :: MessageHeader,
      completionMatches :: [ByteString],
+     completionMatchedText :: ByteString,
      completionText :: ByteString,
      completionStatus :: Bool
   }