Return error when evaluation failed

main/Main.hs

@@ -309,7 +309,10 @@ replyTo _ interface req@ExecuteRequest { getCode = code } replyHeader state = do
   -- Run code and publish to the frontend as we go.
   let widgetMessageHandler = widgetHandler send replyHeader
       publish = publishResult send replyHeader displayed updateNeeded pOut (usePager state)
-  updatedState <- evaluate state (T.unpack code) publish widgetMessageHandler
+  (updatedState, errorOccurred) <- evaluate state (T.unpack code) publish widgetMessageHandler
+  let executeReplyStatus = case errorOccurred of
+        Success -> Ok
+        Failure -> Err
 
   -- Take pager output if we're using the pager.
   pager <- if usePager state
@@ -320,7 +323,7 @@ replyTo _ interface req@ExecuteRequest { getCode = code } replyHeader state = do
                      { header = replyHeader
                      , pagerOutput = pager
                      , executionCounter = execCount
-                     , status = Ok
+                     , status = executeReplyStatus
                      })
 
 -- Check for a trailing empty line. If it doesn't exist, we assume the code is incomplete,

src/IHaskell/Eval/Evaluate.hs

@@ -383,7 +383,7 @@ evaluate :: KernelState                  -- ^ The kernel state.
          -> String                       -- ^ Haskell code or other interpreter commands.
          -> Publisher                    -- ^ Function used to publish data outputs.
          -> (KernelState -> [WidgetMsg] -> IO KernelState) -- ^ Function to handle widget messages
-         -> Interpreter KernelState
+         -> Interpreter (KernelState, ErrorOccurred)
 evaluate kernelState code output widgetHandler = do
   cmds <- parseString (cleanString code)
   let execCount = getExecutionCounter kernelState
@@ -393,7 +393,7 @@ evaluate kernelState code output widgetHandler = do
       justError _ = Nothing
       errs = mapMaybe (justError . unloc) cmds
 
-  updated <- case errs of
+  (updated, errorOccurred) <- case errs of
                -- Only run things if there are no parse errors.
                [] -> do
 
@@ -412,16 +412,16 @@ evaluate kernelState code output widgetHandler = do
                    liftIO $ output
                      (FinalResult (evalResult out) [] [])
                      (evalStatus out)
-                 return kernelState
+                 return (kernelState, Failure)
 
-  return updated { getExecutionCounter = execCount + 1 }
+  return (updated { getExecutionCounter = execCount + 1 }, errorOccurred)
 
   where
     noResults (Display res) = null res
     noResults (ManyDisplay res) = all noResults res
 
-    runUntilFailure :: KernelState -> [CodeBlock] -> Interpreter KernelState
-    runUntilFailure state [] = return state
+    runUntilFailure :: KernelState -> [CodeBlock] -> Interpreter (KernelState, ErrorOccurred)
+    runUntilFailure state [] = return (state, Success)
     runUntilFailure state (cmd:rest) = do
       evalOut <- evalCommand output cmd state
 
@@ -458,7 +458,7 @@ evaluate kernelState code output widgetHandler = do
 
       case evalStatus evalOut of
         Success -> runUntilFailure newState rest
-        Failure -> return newState
+        Failure -> return (newState, Failure)
 
     storeItCommand execCount = Statement $ printf "let it%d = it" execCount