Switched to non-lazy IO for reading.

IHaskell.cabal

@@ -74,4 +74,6 @@ executable IHaskell
                        ghc-paths ==0.1.*,
                        knob ==0.1.*,
                        directory ==1.2.*,
-                       deepseq ==1.3.*
+                       deepseq ==1.3.*,
+                       random ==1.0.*,
+                       strict ==0.3.*

IHaskell/Eval/Evaluate.hs

@@ -8,8 +8,10 @@ module IHaskell.Eval.Evaluate (
 import ClassyPrelude hiding (liftIO, hGetContents)
 import Prelude(putChar, tail, init)
 import Data.List.Utils
+import Data.List(findIndex)
 import Data.String.Utils
 import Text.Printf
+import System.Random
 
 import Language.Haskell.Exts.Parser
 import Language.Haskell.Exts.Pretty
@@ -22,10 +24,15 @@ import GHC hiding (Stmt)
 import GHC.Paths
 import Exception hiding (evaluate)
 
+import qualified System.IO.Strict as StrictIO
+
 import IHaskell.Types
 
+debug :: Bool
+debug = False
+
 write :: GhcMonad m => String -> m ()
-write x = liftIO $ hPutStrLn stderr x
+write x = when debug $ liftIO $ hPutStrLn stderr x
 
 type LineNumber = Int
 type ColumnNumber = Int
@@ -89,19 +96,27 @@ parseCommands code = concatMap makeCommands pieces
     -- Pieces can be declarations, statement lists, or directives.
     -- We distinguish declarations from statements via the first line an
     -- indentation, and directives based on the first character.
-    samePiece x y = not (isDirective x || isDirective y) && indentLevel x <= indentLevel y
     indentLevel (' ':str) = 1 + indentLevel str
     indentLevel _ = 0 :: Int
 
-    pieces = groupBy samePiece $ lines code
+    makePieces :: [String] -> [String]
+    makePieces [] = []
+    makePieces (first:rest)
+      | isDirective first = first : makePieces rest
+      | otherwise = unlines (first:take endOfBlock rest) : makePieces (drop endOfBlock rest)
+          where
+            endOfBlock = fromMaybe (length rest) $ findIndex (\x -> indentLevel x <= indentLevel first) rest
+
+
+    pieces = trace (show $ makePieces $ lines code ) $ makePieces $ lines code
     makeCommands lines
-      | any isDirective lines = map createDirective lines
-      | any isDeclaration lines =
-          case parseDecl $ unlines lines of
+      | isDirective lines = [createDirective lines]
+      | isDeclaration lines =
+          case parseDecl $ trace ("Decl<" ++ lines ++ "<>>>") lines of
             ParseOk declaration -> [Declaration $ prettyPrint declaration]
             ParseFailed srcLoc errMsg -> [ParseError (srcLine srcLoc) (srcColumn srcLoc) errMsg]
       | otherwise = 
-          case parseStmts $ trace (show $ unlines lines) $ unlines lines of
+          case parseStmts $ trace ("STMT<" ++ lines ++ "<s>>") lines of
             Left (srcLine, srcColumn, errMsg) -> [ParseError srcLine srcColumn errMsg]
             Right stmts -> map (Statement . prettyPrint) $ init stmts
     isDeclaration line = any (`isInfixOf` line) ["type", "newtype", "data"]
@@ -127,7 +142,6 @@ evalCommand (Directive directive) = do
 evalCommand (Statement stmt) = do
   write $ "Statement: " ++ stmt
   ghandle handler $ do
-
     (printed, result) <- capturedStatement stmt
     case result of
       RunOk _ ->
@@ -156,10 +170,13 @@ evalCommand (ParseError line col err) =
   return [Display MimeHtml $ makeError $ printf "Error (line %d, column %d): %s" line col err]
 
 capturedStatement :: String -> Interpreter (String, RunResult)
-capturedStatement stmt = 
-  let fileVariable = "ridiculous" :: String
-      fileName = ".capture" :: String
-      oldVariable = fileVariable ++ "'" :: String
+capturedStatement stmt = do
+  -- Generate random variable names to use so that we cannot accidentally
+  -- override the variables by using the right names in the terminal.
+  randStr <- liftIO $ show . abs <$> (randomIO :: IO Int)
+  let fileVariable = "file_var_" ++ randStr :: String
+      fileName = ".ihaskell_capture" :: String
+      oldVariable = fileVariable ++ "_old" :: String
       initStmts :: [String]
       initStmts = [
         printf "%s <- openFile \"%s\" WriteMode" fileVariable fileName,
@@ -170,14 +187,16 @@ capturedStatement stmt =
                "hFlush stdout",
         printf "hDuplicateTo %s stdout" oldVariable,
         printf "hClose %s" fileVariable]
-      goStmt s = runStmt s RunToCompletion in do
+      goStmt s = runStmt s RunToCompletion
 
   forM_ initStmts goStmt
   result <- goStmt stmt
   forM_ postStmts goStmt
 
-    printedOutput <- liftIO $ readFile $ fpFromString fileName
-    liftIO $ print printedOutput
+  -- We must use strict IO, because we write to that file again if we
+  -- execute more statements. If we read lazily, we may cause errors when
+  -- trying to open the file for writing later.
+  printedOutput <- liftIO $ StrictIO.readFile fileName
 
   return (printedOutput, result)
 

IHaskell/ZeroMQ.hs

 -- | The "ZeroMQ" module abstracts away the low-level 0MQ based interface with IPython,
--- | replacing it instead with a Haskell Channel based interface. The `serveProfile` function
--- | takes a IPython profile specification and returns the channel interface to use.
+-- replacing it instead with a Haskell Channel based interface. The `serveProfile` function
+-- takes a IPython profile specification and returns the channel interface to use.
 module IHaskell.ZeroMQ (
   ZeroMQInterface (..),
   serveProfile
@@ -17,7 +17,7 @@ import IHaskell.Types
 import IHaskell.Message.Parser
 import IHaskell.Message.Writer
 
--- The channel interface to the ZeroMQ sockets. All communication is done via
+-- | The channel interface to the ZeroMQ sockets. All communication is done via
 -- Messages, which are encoded and decoded into a lower level form before being
 -- transmitted to IPython. These channels should functionally serve as
 -- high-level sockets which speak Messages instead of ByteStrings.