X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Fghci%2FInteractiveUI.hs;h=e64323cda51614235d75592d6f5983e89caa1ef3;hb=ee43954806848ffbe78f7cb8cf6732c2d86306d2;hp=df05c6e6c22387b13fee35dc826d707aeb8756ea;hpb=acef71564746becef2c85c310ed57dc8fdd54581;p=ghc-hetmet.git

diff --git a/ghc/compiler/ghci/InteractiveUI.hs b/ghc/compiler/ghci/InteractiveUI.hs
index df05c6e..e64323c 100644
--- a/ghc/compiler/ghci/InteractiveUI.hs
+++ b/ghc/compiler/ghci/InteractiveUI.hs
@@ -1,5 +1,5 @@
 -----------------------------------------------------------------------------
--- $Id: InteractiveUI.hs,v 1.5 2000/11/20 16:28:29 simonmar Exp $
+-- $Id: InteractiveUI.hs,v 1.77 2001/06/18 09:09:28 simonmar Exp $
 --
 -- GHC Interactive User Interface
 --
@@ -7,154 +7,351 @@
 --
 -----------------------------------------------------------------------------
 
-module InteractiveUI (interactiveUI) where
+{-# OPTIONS -#include "Linker.h" #-}
+module InteractiveUI ( interactiveUI, ghciWelcomeMsg ) where
 
+#include "../includes/config.h"
 #include "HsVersions.h"
 
+import Packages
 import CompManager
-import CmStaticInfo
+import HscTypes		( GhciMode(..) )
+import ByteCodeLink
 import DriverFlags
-import DriverUtil
 import DriverState
+import DriverUtil
 import Linker
-import Module
-import Outputable
-import Panic
+import Finder		( flushPackageCache )
 import Util
+import Name		( Name )
+import Outputable
+import CmdLineOpts	( DynFlag(..), getDynFlags, saveDynFlags, restoreDynFlags, dopt_unset )
+import Panic		( GhcException(..) )
+import Config
+
+#ifndef mingw32_TARGET_OS
+import Posix
+#endif
 
 import Exception
-import Readline
+import Dynamic
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+import Readline 
+#endif
 import IOExts
 
+import Numeric
+import List
 import System
+import CPUTime
 import Directory
 import IO
 import Char
+import Monad 		( when )
+
+import PrelGHC 		( unsafeCoerce# )
+import Foreign		( nullPtr )
+import CString		( peekCString )
 
 -----------------------------------------------------------------------------
 
 ghciWelcomeMsg = "\ 
-\ _____  __   __  ____         _________________________________________________\n\ 
-\(|	 ||   || (|  |)        GHC Interactive, version 5.00   	                \n\ 
-\||  __  ||___|| ||     ()     For Haskell 98.                    		\n\ 
-\||   |) ||---|| ||     ||     http://www.haskell.org/ghc         		\n\ 
-\||   || ||   || ||     (|     Bug reports to: glasgow-haskell-bugs@haskell.org \n\ 
-\(|___|| ||   || (|__|) \\\\______________________________________________________\n"
-
-commands :: [(String, String -> GHCi ())]
-commands = [
-  ("cd",    	changeDirectory),
-  ("help",	help),
-  ("?",		help),
-  ("load",	loadModule),
-  ("reload",	reloadModule),
-  ("set",	setOptions),
-  ("type",	typeOfExpr),
+\   ___         ___ _\n\ 
+\  / _ \\ /\\  /\\/ __(_)\n\ 
+\ / /_\\// /_/ / /  | |      GHC Interactive, version " ++ cProjectVersion ++ ", for Haskell 98.\n\ 
+\/ /_\\\\/ __  / /___| |      http://www.haskell.org/ghc/\n\ 
+\\\____/\\/ /_/\\____/|_|      Type :? for help.\n"
+
+GLOBAL_VAR(commands, builtin_commands, [(String, String -> GHCi Bool)])
+
+builtin_commands :: [(String, String -> GHCi Bool)]
+builtin_commands = [
+  ("add",	keepGoing addModule),
+  ("cd",    	keepGoing changeDirectory),
+  ("def",	keepGoing defineMacro),
+  ("help",	keepGoing help),
+  ("?",		keepGoing help),
+  ("load",	keepGoing loadModule),
+  ("module",	keepGoing setContext),
+  ("reload",	keepGoing reloadModule),
+  ("set",	keepGoing setOptions),
+  ("type",	keepGoing typeOfExpr),
+  ("unset",	keepGoing unsetOptions),
+  ("undef",     keepGoing undefineMacro),
   ("quit",	quit)
   ]
 
+keepGoing :: (String -> GHCi ()) -> (String -> GHCi Bool)
+keepGoing a str = a str >> return False
+
 shortHelpText = "use :? for help.\n"
 
 helpText = "\ 
-\   <expr>		evaluate <expr>\n\ 
-\   :cd <dir>		change directory to <dir>\n\ 
-\   :help		display this list of commands\n\ 
-\   :?			display this list of commands\n\ 
-\   :load <filename>    load a module (and it dependents)\n\ 
-\   :reload		reload the current program\n\ 
-\   :set <opetion> ...	set options\n\ 
-\   :type <expr>	show the type of <expr>\n\ 
-\   :quit		exit GHCi\n\ 
-\   :!<command>		run the shell command <command>\n\ 
+\ Commands available from the prompt:\n\ 
+\\  
+\   <stmt>		   evaluate/run <stmt>\n\ 
+\   :cd <dir>		   change directory to <dir>\n\ 
+\   :def <cmd> <expr>      define a command :<cmd>\n\ 
+\   :help, :?		   display this list of commands\n\ 
+\   :load <filename>       load a module (and its dependents)\n\ 
+\   :module <mod>	   set the context for expression evaluation to <mod>\n\ 
+\   :reload		   reload the current module set\n\ 
+\   :set <option> ...	   set options\n\ 
+\   :undef <cmd> 	   undefine user-defined command :<cmd>\n\ 
+\   :type <expr>	   show the type of <expr>\n\ 
+\   :unset <option> ...	   unset options\n\ 
+\   :quit		   exit GHCi\n\ 
+\   :!<command>		   run the shell command <command>\n\ 
+\\ 
+\ Options for `:set' and `:unset':\n\ 
+\\ 
+\    +r			revert top-level expressions after each evaluation\n\ 
+\    +s                 print timing/memory stats after each evaluation\n\ 
+\    +t			print type after evaluation\n\ 
+\    -<flags>		most GHC command line flags can also be set here\n\ 
+\                         (eg. -v2, -fglasgow-exts, etc.)\n\ 
 \"
+ --ToDo   :add <filename>     add a module to the current set\n\ 
 
-interactiveUI :: CmState -> IO ()
-interactiveUI st = do
-   hPutStrLn stdout ghciWelcomeMsg
+interactiveUI :: CmState -> Maybe FilePath -> [LibrarySpec] -> IO ()
+interactiveUI cmstate mod cmdline_libs = do
    hFlush stdout
    hSetBuffering stdout NoBuffering
 
    -- link in the available packages
    pkgs <- getPackageInfo
-   linkPackages (reverse pkgs)
+   initLinker
+   linkPackages cmdline_libs pkgs
 
-#ifndef NO_READLINE
+   (cmstate, ok, mods) <-
+   	case mod of
+	     Nothing  -> return (cmstate, True, [])
+	     Just m -> cmLoadModule cmstate m
+
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
    Readline.initialize
 #endif
-   _ <- (unGHCi uiLoop) GHCiState{ modules = [],
-				   current_module = Nothing, 
-	  	                   target = Nothing,
-			           cmstate = st }
+
+   dflags <- getDynFlags
+
+   (cmstate, maybe_hval) 
+	<- cmCompileExpr cmstate dflags "IO.hFlush PrelHandle.stderr"
+   case maybe_hval of
+	Just hval -> writeIORef flush_stderr (unsafeCoerce# hval :: IO ())
+	_ -> panic "interactiveUI:stderr"
+
+   (cmstate, maybe_hval) 
+	<- cmCompileExpr cmstate dflags "IO.hFlush PrelHandle.stdout"
+   case maybe_hval of
+	Just hval -> writeIORef flush_stdout (unsafeCoerce# hval :: IO ())
+	_ -> panic "interactiveUI:stdout"
+
+   startGHCi runGHCi GHCiState{ target = mod,
+			        cmstate = cmstate,
+			        options = [] }
    return ()
 
-uiLoop :: GHCi ()
-uiLoop = do
-  st <- getGHCiState
-#ifndef NO_READLINE
-  l <- io (readline (mkPrompt (current_module st)  ++ "> "))
+
+runGHCi :: GHCi ()
+runGHCi = do
+  -- Read in ./.ghci.
+  let file = "./.ghci"
+  exists <- io (doesFileExist file)
+  when exists $ do
+     dir_ok  <- io (checkPerms ".")
+     file_ok <- io (checkPerms file)
+     when (dir_ok && file_ok) $ do
+   	either_hdl <- io (IO.try (openFile "./.ghci" ReadMode))
+   	case either_hdl of
+   	   Left e    -> return ()
+   	   Right hdl -> fileLoop hdl False
+  
+  -- Read in $HOME/.ghci
+  either_dir <- io (IO.try (getEnv "HOME"))
+  case either_dir of
+     Left e -> return ()
+     Right dir -> do
+	cwd <- io (getCurrentDirectory)
+    	when (dir /= cwd) $ do
+	   let file = dir ++ "/.ghci"
+	   ok <- io (checkPerms file)
+       	   either_hdl <- io (IO.try (openFile file ReadMode))
+	   case either_hdl of
+		Left e    -> return ()
+		Right hdl -> fileLoop hdl False
+
+  -- read commands from stdin
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+  readlineLoop
 #else
-  l <- io (hGetLine stdin)
+  fileLoop stdin True
 #endif
-  case l of
-    Nothing -> return ()
-    Just "" -> uiLoop
-    Just l  -> do
-#ifndef NO_READLINE
-          io (addHistory l)
+
+  -- and finally, exit
+  io $ do putStrLn "Leaving GHCi." 
+
+
+-- NOTE: We only read .ghci files if they are owned by the current user,
+-- and aren't world writable.  Otherwise, we could be accidentally 
+-- running code planted by a malicious third party.
+
+-- Furthermore, We only read ./.ghci if both . and ./.ghci are
+-- owned by the current user and aren't writable by anyone else.  I
+-- think this is sufficient: we don't need to check .. and
+-- ../.. etc. because "."  always refers to the same directory while a
+-- process is running.
+
+checkPerms :: String -> IO Bool
+checkPerms name =
+  handle (\_ -> return False) $ do
+#ifdef mingw32_TARGET_OS
+     doesFileExist name
+#else
+     st <- getFileStatus name
+     me <- getRealUserID
+     if fileOwner st /= me then do
+   	putStrLn $ "WARNING: " ++ name ++ " is owned by someone else, IGNORING!"
+   	return False
+      else do
+   	let mode =  fileMode st
+   	if (groupWriteMode == (mode `intersectFileModes` groupWriteMode))
+   	   || (otherWriteMode == (mode `intersectFileModes` otherWriteMode)) 
+   	   then do
+   	       putStrLn $ "*** WARNING: " ++ name ++ 
+   			  " is writable by someone else, IGNORING!"
+   	       return False
+   	  else return True
 #endif
-  	  runCommand l
-	  uiLoop  
 
-mkPrompt Nothing = "> "
-mkPrompt (Just mod_name) = moduleNameUserString mod_name
+fileLoop :: Handle -> Bool -> GHCi ()
+fileLoop hdl prompt = do
+   st <- getGHCiState
+   mod <- io (cmGetContext (cmstate st))
+   when prompt (io (putStr (mod ++ "> ")))
+   l <- io (IO.try (hGetLine hdl))
+   case l of
+	Left e | isEOFError e -> return ()
+	       | otherwise    -> throw e
+	Right l -> 
+	  case remove_spaces l of
+	    "" -> fileLoop hdl prompt
+	    l  -> do quit <- runCommand l
+          	     if quit then return () else fileLoop hdl prompt
+
+stringLoop :: [String] -> GHCi ()
+stringLoop [] = return ()
+stringLoop (s:ss) = do
+   st <- getGHCiState
+   case remove_spaces s of
+	"" -> stringLoop ss
+	l  -> do quit <- runCommand l
+                 if quit then return () else stringLoop ss
+
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+readlineLoop :: GHCi ()
+readlineLoop = do
+   st <- getGHCiState
+   mod <- io (cmGetContext (cmstate st))
+   l <- io (readline (mod ++ "> "))
+   case l of
+	Nothing -> return ()
+	Just l  ->
+	  case remove_spaces l of
+	    "" -> readlineLoop
+	    l  -> do
+        	  io (addHistory l)
+  	  	  quit <- runCommand l
+          	  if quit then return () else readlineLoop
+#endif
 
 -- Top level exception handler, just prints out the exception 
 -- and carries on.
+runCommand :: String -> GHCi Bool
 runCommand c = 
-  ghciHandle ( \other_exception ->io (putStrLn (show other_exception) )) $
-  ghciHandleDyn
-    (\dyn -> case dyn of
-		PhaseFailed phase code ->
-			io ( putStrLn ("Phase " ++ phase ++ " failed (code "
-				        ++ show code ++ ")"))
-		Interrupted -> io (putStrLn "Interrupted.")
-		_ -> io (putStrLn (show (dyn :: BarfKind)))
-    ) $
-   doCommand c
+  ghciHandle ( \exception -> do
+		flushEverything
+		showException exception
+		return False
+	     ) $
+  doCommand c
+
+showException (DynException dyn) =
+  case fromDynamic dyn of
+    Nothing -> 
+	io (putStrLn ("*** Exception: (unknown)"))
+    Just (PhaseFailed phase code) ->
+	io (putStrLn ("Phase " ++ phase ++ " failed (code "
+		       ++ show code ++ ")"))
+    Just Interrupted ->
+	io (putStrLn "Interrupted.")
+    Just (CmdLineError s) -> 
+	io (putStrLn s)	 -- omit the location for CmdLineError
+    Just other_ghc_ex ->
+	io (putStrLn (show other_ghc_ex))
+showException other_exception
+  = io (putStrLn ("*** Exception: " ++ show other_exception))
 
 doCommand (':' : command) = specialCommand command
-doCommand expr = do
-  st <- getGHCiState
-  case current_module st of
-	Nothing -> throwDyn (OtherError "no module context in which to run the expression")
-	Just mod -> do
-             dflags <- io (readIORef v_DynFlags)
-             (st, maybe_hvalue) <- 
-        	io (cmGetExpr (cmstate st) dflags mod expr)
-             case maybe_hvalue of
-        	Nothing -> return ()
-        	Just hv -> io (cmRunExpr hv)
-{-
-  let (mod,'.':str) = break (=='.') expr
-  case cmLookupSymbol (mkOrig varName (mkModuleName mod) (_PK_ str)) (cmstate st) of
-	Nothing -> io (putStrLn "nothing.")
-	Just e  -> io (
-  return ()
--}
-
+doCommand stmt
+   = do timeIt (do stuff <- runStmt stmt; finishEvalExpr stuff)
+        return False
+
+-- Returns True if the expr was successfully parsed, renamed and
+-- typechecked.
+runStmt :: String -> GHCi (Maybe [Name])
+runStmt stmt
+ | null (filter (not.isSpace) stmt)
+ = return Nothing
+ | otherwise
+ = do st <- getGHCiState
+      dflags <- io getDynFlags
+      let dflags' = dopt_unset dflags Opt_WarnUnusedBinds
+      (new_cmstate, names) <- io (cmRunStmt (cmstate st) dflags' stmt)
+      setGHCiState st{cmstate = new_cmstate}
+      return (Just names)
+
+-- possibly print the type and revert CAFs after evaluating an expression
+finishEvalExpr Nothing = return False
+finishEvalExpr (Just names)
+ = do b <- isOptionSet ShowType
+      st <- getGHCiState
+      when b (mapM_ (showTypeOfName (cmstate st)) names)
+
+      b <- isOptionSet RevertCAFs
+      io (when b revertCAFs)
+      flushEverything
+      return True
+
+showTypeOfName :: CmState -> Name -> GHCi ()
+showTypeOfName cmstate n
+   = do maybe_str <- io (cmTypeOfName cmstate n)
+	case maybe_str of
+	  Nothing  -> return ()
+	  Just str -> io (putStrLn (showSDoc (ppr n) ++ " :: " ++ str))
+
+flushEverything :: GHCi ()
+flushEverything
+   = io $ do flush_so <- readIORef flush_stdout
+     	     flush_so
+     	     flush_se <- readIORef flush_stdout
+     	     flush_se
+             return ()
+
+specialCommand :: String -> GHCi Bool
 specialCommand ('!':str) = shellEscape (dropWhile isSpace str)
 specialCommand str = do
   let (cmd,rest) = break isSpace str
-  case [ (s,f) | (s,f) <- commands, prefixMatch cmd s ] of
-     []      -> io $ hPutStr stdout ("uknown command `:" ++ cmd ++ "'\n" 
-				    ++ shortHelpText)
+  cmds <- io (readIORef commands)
+  case [ (s,f) | (s,f) <- cmds, prefixMatch cmd s ] of
+     []      -> io (hPutStr stdout ("unknown command `:" ++ cmd ++ "'\n" 
+		                    ++ shortHelpText) >> return False)
      [(_,f)] -> f (dropWhile isSpace rest)
-     cs      -> io $ hPutStrLn stdout ("prefix " ++ cmd ++ 
-			    	       " matches multiple commands (" ++ 
+     cs      -> io (hPutStrLn stdout ("prefix " ++ cmd ++ 
+			    	      " matches multiple commands (" ++ 
 	         	     	       foldr1 (\a b -> a ++ ',':b) (map fst cs)
-					 ++ ")")
+					 ++ ")") >> return False)
 
-noArgs c = io (hPutStrLn stdout ("command `:" ++ c ++ "' takes no arguments"))
+noArgs c = throwDyn (CmdLineError ("command `" ++ c ++ "' takes no arguments"))
 
 -----------------------------------------------------------------------------
 -- Commands
@@ -162,43 +359,128 @@ noArgs c = io (hPutStrLn stdout ("command `:" ++ c ++ "' takes no arguments"))
 help :: String -> GHCi ()
 help _ = io (putStr helpText)
 
+addModule :: String -> GHCi ()
+addModule _ = throwDyn (InstallationError ":add not implemented")
+
+setContext :: String -> GHCi ()
+setContext ""
+  = throwDyn (CmdLineError "syntax: `:m <module>'")
+setContext m | not (isUpper (head m)) || not (all isAlphaNumEx (tail m))
+  = throwDyn (CmdLineError ("strange looking module name: `" ++ m ++ "'"))
+    where
+       isAlphaNumEx c = isAlphaNum c || c == '_'
+setContext str
+  = do st <- getGHCiState
+       new_cmstate <- io (cmSetContext (cmstate st) str)
+       setGHCiState st{cmstate=new_cmstate}
+
 changeDirectory :: String -> GHCi ()
-changeDirectory = io . setCurrentDirectory
+changeDirectory ('~':d) = do
+   tilde <- io (getEnv "HOME")	-- will fail if HOME not defined
+   io (setCurrentDirectory (tilde ++ '/':d))
+changeDirectory d = io (setCurrentDirectory d)
+
+defineMacro :: String -> GHCi ()
+defineMacro s = do
+  let (macro_name, definition) = break isSpace s
+  cmds <- io (readIORef commands)
+  if (null macro_name) 
+	then throwDyn (CmdLineError "invalid macro name") 
+	else do
+  if (macro_name `elem` map fst cmds) 
+	then throwDyn (CmdLineError 
+		("command `" ++ macro_name ++ "' is already defined"))
+	else do
+
+  -- give the expression a type signature, so we can be sure we're getting
+  -- something of the right type.
+  let new_expr = '(' : definition ++ ") :: String -> IO String"
+
+  -- compile the expression
+  st <- getGHCiState
+  dflags <- io getDynFlags
+  (new_cmstate, maybe_hv) <- io (cmCompileExpr (cmstate st) dflags new_expr)
+  setGHCiState st{cmstate = new_cmstate}
+  case maybe_hv of
+     Nothing -> return ()
+     Just hv -> io (writeIORef commands --
+		    ((macro_name, keepGoing (runMacro hv)) : cmds))
+
+runMacro :: HValue{-String -> IO String-} -> String -> GHCi ()
+runMacro fun s = do
+  str <- io ((unsafeCoerce# fun :: String -> IO String) s)
+  stringLoop (lines str)
+
+undefineMacro :: String -> GHCi ()
+undefineMacro macro_name = do
+  cmds <- io (readIORef commands)
+  if (macro_name `elem` map fst builtin_commands) 
+	then throwDyn (CmdLineError
+		("command `" ++ macro_name ++ "' cannot be undefined"))
+	else do
+  if (macro_name `notElem` map fst cmds) 
+	then throwDyn (CmdLineError 
+		("command `" ++ macro_name ++ "' not defined"))
+	else do
+  io (writeIORef commands (filter ((/= macro_name) . fst) cmds))
 
 loadModule :: String -> GHCi ()
-loadModule path = do
+loadModule path = timeIt (loadModule' path)
+
+loadModule' path = do
+  state <- getGHCiState
+  dflags <- io getDynFlags
+  cmstate1 <- io (cmUnload (cmstate state) dflags)
+  setGHCiState state{ cmstate = cmstate1, target = Nothing }
+  io (revertCAFs)			-- always revert CAFs on load.
+  (cmstate2, ok, mods) <- io (cmLoadModule cmstate1 path)
+  setGHCiState state{ cmstate = cmstate2, target = Just path }
+  modulesLoadedMsg ok mods
+
+reloadModule :: String -> GHCi ()
+reloadModule "" = do
   state <- getGHCiState
-  (new_cmstate, ok, mods) <- io (cmLoadModule (cmstate state) path)
-
-  let new_state = GHCiState {
-  			cmstate = new_cmstate,
-			modules = mods,
-			current_module = case mods of 
-					   [] -> Nothing
-					   xs -> Just (last xs),
-			target = Just path
-		   }
-  setGHCiState new_state
+  case target state of
+   Nothing -> io (putStr "no current target\n")
+   Just path
+      -> do io (revertCAFs)		-- always revert CAFs on reload.
+	    (new_cmstate, ok, mods) <- io (cmLoadModule (cmstate state) path)
+            setGHCiState state{ cmstate=new_cmstate }
+	    modulesLoadedMsg ok mods
+
+reloadModule _ = noArgs ":reload"
 
+
+modulesLoadedMsg ok mods = do
   let mod_commas 
 	| null mods = text "none."
 	| otherwise = hsep (
-	    punctuate comma (map (text.moduleNameUserString) mods)) <> text "."
+	    punctuate comma (map text mods)) <> text "."
   case ok of
     False -> 
        io (putStrLn (showSDoc (text "Failed, modules loaded: " <> mod_commas)))
     True  -> 
        io (putStrLn (showSDoc (text "Ok, modules loaded: " <> mod_commas)))
 
-reloadModule :: String -> GHCi ()
-reloadModule "" = do
-  state <- getGHCiState
-  case target state of
-   Nothing -> io (putStr "no current target\n")
-   Just path -> do (new_cmstate, ok, mod) 
-			<- io (cmLoadModule (cmstate state) path)
-  		   setGHCiState state{cmstate=new_cmstate}  
-reloadModule _ = noArgs ":reload"
+
+typeOfExpr :: String -> GHCi ()
+typeOfExpr str 
+  = do st <- getGHCiState
+       dflags <- io getDynFlags
+       (new_cmstate, maybe_tystr) <- io (cmTypeOfExpr (cmstate st) dflags str)
+       setGHCiState st{cmstate = new_cmstate}
+       case maybe_tystr of
+	  Nothing    -> return ()
+	  Just tystr -> io (putStrLn tystr)
+
+quit :: String -> GHCi Bool
+quit _ = return True
+
+shellEscape :: String -> GHCi Bool
+shellEscape str = io (system str >> return False)
+
+----------------------------------------------------------------------------
+-- Code for `:set'
 
 -- set options in the interpreter.  Syntax is exactly the same as the
 -- ghc command line, except that certain options aren't available (-C,
@@ -206,80 +488,306 @@ reloadModule _ = noArgs ":reload"
 --
 -- This is pretty fragile: most options won't work as expected.  ToDo:
 -- figure out which ones & disallow them.
+
 setOptions :: String -> GHCi ()
-setOptions str =
-   io (do leftovers <- processArgs static_flags (words str) []
-	  dyn_flags <- readIORef v_InitDynFlags
-	  writeIORef v_DynFlags dyn_flags
-	  leftovers <- processArgs dynamic_flags leftovers []
-	  dyn_flags <- readIORef v_DynFlags
-	  writeIORef v_InitDynFlags dyn_flags
-          if (not (null leftovers))
-		then throwDyn (OtherError ("unrecognised flags: " ++ 
+setOptions ""
+  = do st <- getGHCiState
+       let opts = options st
+       io $ putStrLn (showSDoc (
+   	      text "options currently set: " <> 
+   	      if null opts
+   		   then text "none."
+   		   else hsep (map (\o -> char '+' <> text (optToStr o)) opts)
+   	   ))
+setOptions str
+  = do -- first, deal with the GHCi opts (+s, +t, etc.)
+      let (plus_opts, minus_opts)  = partition isPlus (words str)
+      mapM setOpt plus_opts
+
+      -- now, the GHC flags
+      pkgs_before <- io (readIORef v_Packages)
+      leftovers   <- io (processArgs static_flags minus_opts [])
+      pkgs_after  <- io (readIORef v_Packages)
+
+      -- update things if the users wants more packages
+      when (pkgs_before /= pkgs_after) $
+	 newPackages (pkgs_after \\ pkgs_before)
+
+      -- then, dynamic flags
+      io $ do 
+	restoreDynFlags
+        leftovers <- processArgs dynamic_flags leftovers []
+	saveDynFlags
+
+        if (not (null leftovers))
+		then throwDyn (CmdLineError ("unrecognised flags: " ++ 
 						unwords leftovers))
 		else return ()
-   )
 
-typeOfExpr :: String -> GHCi ()
-typeOfExpr = panic "typeOfExpr"
 
-quit :: String -> GHCi ()
-quit _ = return ()
+unsetOptions :: String -> GHCi ()
+unsetOptions str
+  = do -- first, deal with the GHCi opts (+s, +t, etc.)
+       let opts = words str
+	   (minus_opts, rest1) = partition isMinus opts
+	   (plus_opts, rest2)  = partition isPlus rest1
+
+       if (not (null rest2)) 
+	  then io (putStrLn ("unknown option: `" ++ head rest2 ++ "'"))
+	  else do
+
+       mapM unsetOpt plus_opts
+ 
+       -- can't do GHC flags for now
+       if (not (null minus_opts))
+	  then throwDyn (CmdLineError "can't unset GHC command-line flags")
+	  else return ()
+
+isMinus ('-':s) = True
+isMinus _ = False
+
+isPlus ('+':s) = True
+isPlus _ = False
+
+setOpt ('+':str)
+  = case strToGHCiOpt str of
+	Nothing -> io (putStrLn ("unknown option: `" ++ str ++ "'"))
+	Just o  -> setOption o
+
+unsetOpt ('+':str)
+  = case strToGHCiOpt str of
+	Nothing -> io (putStrLn ("unknown option: `" ++ str ++ "'"))
+	Just o  -> unsetOption o
+
+strToGHCiOpt :: String -> (Maybe GHCiOption)
+strToGHCiOpt "s" = Just ShowTiming
+strToGHCiOpt "t" = Just ShowType
+strToGHCiOpt "r" = Just RevertCAFs
+strToGHCiOpt _   = Nothing
+
+optToStr :: GHCiOption -> String
+optToStr ShowTiming = "s"
+optToStr ShowType   = "t"
+optToStr RevertCAFs = "r"
+
+newPackages new_pkgs = do
+  state <- getGHCiState
+  dflags <- io getDynFlags
+  cmstate1 <- io (cmUnload (cmstate state) dflags)
+  setGHCiState state{ cmstate = cmstate1, target = Nothing }
 
-shellEscape :: String -> GHCi ()
-shellEscape str = io (system str >> return ())
+  io $ do
+    pkgs <- getPackageInfo
+    flushPackageCache pkgs
+   
+    new_pkg_info <- getPackageDetails new_pkgs
+    mapM_ (linkPackage False) (reverse new_pkg_info)
 
 -----------------------------------------------------------------------------
 -- GHCi monad
 
 data GHCiState = GHCiState
      { 
-	modules	       :: [ModuleName],
-	current_module :: Maybe ModuleName,
 	target         :: Maybe FilePath,
-	cmstate        :: CmState
+	cmstate        :: CmState,
+	options        :: [GHCiOption]
      }
 
-newtype GHCi a = GHCi { unGHCi :: GHCiState -> IO (GHCiState, a) }
+data GHCiOption 
+	= ShowTiming		-- show time/allocs after evaluation
+	| ShowType		-- show the type of expressions
+	| RevertCAFs		-- revert CAFs after every evaluation
+	deriving Eq
+
+GLOBAL_VAR(flush_stdout, error "no flush_stdout", IO ())
+GLOBAL_VAR(flush_stderr, error "no flush_stdout", IO ())
+
+newtype GHCi a = GHCi { unGHCi :: IORef GHCiState -> IO a }
+
+startGHCi :: GHCi a -> GHCiState -> IO a
+startGHCi g state = do ref <- newIORef state; unGHCi g ref
 
 instance Monad GHCi where
-  (GHCi m) >>= k  =  GHCi $ \s -> m s >>= \(s,a) -> unGHCi (k a) s
-  return a  = GHCi $ \s -> return (s,a)
+  (GHCi m) >>= k  =  GHCi $ \s -> m s >>= \a -> unGHCi (k a) s
+  return a  = GHCi $ \s -> return a
+
+getGHCiState   = GHCi $ \r -> readIORef r
+setGHCiState s = GHCi $ \r -> writeIORef r s
+
+isOptionSet :: GHCiOption -> GHCi Bool
+isOptionSet opt
+ = do st <- getGHCiState
+      return (opt `elem` options st)
+
+setOption :: GHCiOption -> GHCi ()
+setOption opt
+ = do st <- getGHCiState
+      setGHCiState (st{ options = opt : filter (/= opt) (options st) })
+
+unsetOption :: GHCiOption -> GHCi ()
+unsetOption opt
+ = do st <- getGHCiState
+      setGHCiState (st{ options = filter (/= opt) (options st) })
 
-getGHCiState   = GHCi $ \s -> return (s,s)
-setGHCiState s = GHCi $ \_ -> return (s,())
+io m = GHCi $ \s -> m >>= \a -> return a
 
-io m = GHCi $ \s -> m >>= \a -> return (s,a)
+-----------------------------------------------------------------------------
+-- recursive exception handlers
+
+-- Don't forget to unblock async exceptions in the handler, or if we're
+-- in an exception loop (eg. let a = error a in a) the ^C exception
+-- may never be delivered.  Thanks to Marcin for pointing out the bug.
 
+ghciHandle :: (Exception -> GHCi a) -> GHCi a -> GHCi a
 ghciHandle h (GHCi m) = GHCi $ \s -> 
-   Exception.catch (m s) (\e -> unGHCi (h e) s)
-ghciHandleDyn h (GHCi m) = GHCi $ \s -> 
-   Exception.catchDyn (m s) (\e -> unGHCi (h e) s)
+   Exception.catch (m s) 
+	(\e -> unGHCi (ghciHandle h (ghciUnblock (h e))) s)
+
+ghciUnblock :: GHCi a -> GHCi a
+ghciUnblock (GHCi a) = GHCi $ \s -> Exception.unblock (a s)
 
 -----------------------------------------------------------------------------
 -- package loader
 
-linkPackages :: [Package] -> IO ()
-linkPackages pkgs = mapM_ linkPackage pkgs
-
-linkPackage :: Package -> IO ()
+-- Left: full path name of a .o file, including trailing .o
+-- Right: "unadorned" name of a .DLL/.so
+--        e.g.    On unix     "qt"  denotes "libqt.so"
+--                On WinDoze  "burble"  denotes "burble.DLL"
+--        addDLL is platform-specific and adds the lib/.so/.DLL
+--        suffixes platform-dependently; we don't do that here.
+-- 
+-- For dynamic objects only, try to find the object file in all the 
+-- directories specified in v_Library_Paths before giving up.
+
+type LibrarySpec
+   = Either FilePath String
+
+showLS (Left nm)  = "(static) " ++ nm
+showLS (Right nm) = "(dynamic) " ++ nm
+
+linkPackages :: [LibrarySpec] -> [PackageConfig] -> IO ()
+linkPackages cmdline_lib_specs pkgs
+   = do sequence_ [ linkPackage (name p `elem` loaded) p | p <- reverse pkgs ]
+        lib_paths <- readIORef v_Library_paths
+        mapM_ (preloadLib lib_paths) cmdline_lib_specs
+     where
+	-- packages that are already linked into GHCi
+	loaded = [ "gmp", "rts", "std", "concurrent", "posix", "text", "util" ]
+
+        preloadLib :: [String] -> LibrarySpec -> IO ()
+        preloadLib lib_paths lib_spec
+           = do putStr ("Loading object " ++ showLS lib_spec ++ " ... ")
+                case lib_spec of
+                   Left static_ish
+                      -> do b <- preload_static lib_paths static_ish
+                            putStrLn (if b then "done" else "not found")
+                   Right dll_unadorned
+                      -> -- We add "" to the set of paths to try, so that
+                         -- if none of the real paths match, we force addDLL
+                         -- to look in the default dynamic-link search paths.
+                         do b <- preload_dynamic (lib_paths++[""]) dll_unadorned
+                            when (not b) (cantFind lib_paths lib_spec)
+                            putStrLn "done"
+
+        cantFind :: [String] -> LibrarySpec -> IO ()
+        cantFind paths spec
+           = do putStr ("failed.\nCan't find " ++ showLS spec
+                        ++ " in directories:\n"
+                        ++ unlines (map ("   "++) paths) )
+                give_up
+
+        -- not interested in the paths in the static case.
+        preload_static paths name
+           = do b <- doesFileExist name
+                if not b then return False
+                         else loadObj name >> return True
+
+        preload_dynamic [] name
+           = return False
+        preload_dynamic (path:paths) rootname
+           = do maybe_errmsg <- addDLL path rootname
+                if    maybe_errmsg /= nullPtr
+                 then preload_dynamic paths rootname
+                 else return True
+
+        give_up 
+           = (throwDyn . CmdLineError)
+                "user specified .o/.so/.DLL could not be loaded."
+
+
+linkPackage :: Bool -> PackageConfig -> IO ()
 -- ignore rts and gmp for now (ToDo; better?)
-linkPackage pkg | name pkg `elem` ["rts", "gmp"] = return ()
-linkPackage pkg = do
-  putStr ("Loading package " ++ name pkg ++ " ... ")
-  let dirs = library_dirs pkg
-  let objs = map (++".o") (hs_libraries pkg ++ extra_libraries pkg)
-  mapM (linkOneObj dirs) objs
-  putStr "resolving ... "
-  resolveObjs
-  putStrLn "done."
-
-linkOneObj dirs obj = do
-  filename <- findFile dirs obj
-  loadObj filename
-
-findFile [] obj = throwDyn (OtherError ("can't find " ++ obj))
-findFile (d:ds) obj = do
-  let path = d ++ '/':obj
-  b <- doesFileExist path
-  if b then return path else findFile ds obj
+linkPackage loaded_in_ghci pkg
+   | name pkg `elem` ["rts", "gmp"] 
+   = return ()
+   | otherwise
+   = do putStr ("Loading package " ++ name pkg ++ " ... ")
+        -- For each obj, try obj.o and if that fails, obj.so.
+        -- Complication: all the .so's must be loaded before any of the .o's.  
+        let dirs      =  library_dirs pkg
+        let objs      =  hs_libraries pkg ++ extra_libraries pkg
+        classifieds   <- mapM (locateOneObj dirs) objs
+
+	-- Don't load the .so libs if this is a package GHCi is already
+	-- linked against, because we'll already have the .so linked in.
+	let (so_libs, obj_libs) = partition isRight classifieds
+        let sos_first | loaded_in_ghci = obj_libs
+		      | otherwise      = so_libs ++ obj_libs
+
+        mapM loadClassified sos_first
+        putStr "linking ... "
+        resolveObjs
+        putStrLn "done."
+     where
+        isRight (Right _) = True
+        isRight (Left _)  = False
+
+loadClassified :: LibrarySpec -> IO ()
+loadClassified (Left obj_absolute_filename)
+   = do loadObj obj_absolute_filename
+loadClassified (Right dll_unadorned)
+   = do maybe_errmsg <- addDLL "" dll_unadorned -- doesn't seem right to me
+        if    maybe_errmsg == nullPtr
+         then return ()
+         else do str <- peekCString maybe_errmsg
+                 throwDyn (CmdLineError ("can't find .o or .so/.DLL for: " 
+                                       ++ dll_unadorned ++ " (" ++ str ++ ")" ))
+
+locateOneObj :: [FilePath] -> String -> IO LibrarySpec
+locateOneObj []     obj 
+   = return (Right obj) -- we assume
+locateOneObj (d:ds) obj 
+   = do let path = d ++ '/':obj ++ ".o"
+        b <- doesFileExist path
+        if b then return (Left path) else locateOneObj ds obj
+
+-----------------------------------------------------------------------------
+-- timing & statistics
+
+timeIt :: GHCi a -> GHCi a
+timeIt action
+  = do b <- isOptionSet ShowTiming
+       if not b 
+	  then action 
+	  else do allocs1 <- io $ getAllocations
+		  time1   <- io $ getCPUTime
+		  a <- action
+		  allocs2 <- io $ getAllocations
+		  time2   <- io $ getCPUTime
+		  io $ printTimes (allocs2 - allocs1) (time2 - time1)
+		  return a
+
+foreign import "getAllocations" getAllocations :: IO Int
+
+printTimes :: Int -> Integer -> IO ()
+printTimes allocs psecs
+   = do let secs = (fromIntegral psecs / (10^12)) :: Float
+	    secs_str = showFFloat (Just 2) secs
+	putStrLn (showSDoc (
+		 parens (text (secs_str "") <+> text "secs" <> comma <+> 
+			 int allocs <+> text "bytes")))
+
+-----------------------------------------------------------------------------
+-- reverting CAFs
+	
+foreign import revertCAFs :: IO ()	-- make it "safe", just in case