X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Fghci%2FInteractiveUI.hs;h=5205d716012237935bdd456b2af5ea7d96421eb3;hb=3de6e40ef77ee8f620eb9388725290c0e83b774a;hp=3f4ec2ae421e7747f3e0cf6a99dafd20b42ef91c;hpb=bd915098b155d5797ab768f9880b4051626cb038;p=ghc-hetmet.git

diff --git a/ghc/compiler/ghci/InteractiveUI.hs b/ghc/compiler/ghci/InteractiveUI.hs
index 3f4ec2a..5205d71 100644
--- a/ghc/compiler/ghci/InteractiveUI.hs
+++ b/ghc/compiler/ghci/InteractiveUI.hs
@@ -1,39 +1,62 @@
+{-# OPTIONS -#include "Linker.h" -#include "SchedAPI.h" #-}
 -----------------------------------------------------------------------------
--- $Id: InteractiveUI.hs,v 1.49 2001/02/13 18:37:53 qrczak Exp $
+-- $Id: InteractiveUI.hs,v 1.116 2002/02/28 10:15:47 simonmar Exp $
 --
 -- GHC Interactive User Interface
 --
 -- (c) The GHC Team 2000
 --
 -----------------------------------------------------------------------------
-
-{-# OPTIONS -#include "Linker.h" #-}
 module InteractiveUI ( interactiveUI, ghciWelcomeMsg ) where
 
+#include "../includes/config.h"
 #include "HsVersions.h"
 
+import Packages
+
 import CompManager
-import CmStaticInfo
-import ByteCodeLink
+import CmTypes		( Linkable, isObjectLinkable, ModSummary(..) )
+import CmLink		( findModuleLinkable_maybe )
+
+import HscTypes		( TyThing(..), showModMsg, InteractiveContext(..) )
+import HsSyn		( TyClDecl(..), ConDecl(..), Sig(..) )
+import MkIface		( ifaceTyThing )
 import DriverFlags
 import DriverState
-import DriverUtil
-import Type
+import DriverUtil	( handle, remove_spaces )
 import Linker
-import Finder
-import Module
-import Outputable
+import Finder		( flushPackageCache )
 import Util
-import PprType		{- instance Outputable Type; do not delete -}
-import Panic		( GhcException(..) )
+import Id		( isRecordSelector, recordSelectorFieldLabel, 
+			  isDataConWrapId, isDataConId, idName )
+import Class		( className )
+import TyCon		( tyConName, tyConClass_maybe, isPrimTyCon, DataConDetails(..) )
+import FieldLabel	( fieldLabelTyCon )
+import SrcLoc		( isGoodSrcLoc )
+import Module		( moduleName )
+import NameEnv		( nameEnvElts )
+import Name		( Name, isHomePackageName, nameSrcLoc, nameOccName,
+			  NamedThing(..) )
+import OccName		( isSymOcc )
+import BasicTypes	( defaultFixity )
+import Outputable
+import CmdLineOpts	( DynFlag(..), DynFlags(..), getDynFlags, saveDynFlags,
+			  restoreDynFlags, dopt_unset )
+import Panic		( GhcException(..), showGhcException )
 import Config
 
+#ifndef mingw32_TARGET_OS
+import Posix
+#endif
+
 import Exception
 import Dynamic
-#ifndef NO_READLINE
-import Readline
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+import Readline 
 #endif
+import Concurrent
 import IOExts
+import SystemExts
 
 import Numeric
 import List
@@ -42,19 +65,19 @@ import CPUTime
 import Directory
 import IO
 import Char
-import Monad 		( when )
+import Monad
+
+import GlaExts		( unsafeCoerce# )
 
-import PrelGHC 		( unsafeCoerce# )
-import PrelPack 	( packString )
-import PrelByteArr
-import Foreign		( Ptr, nullPtr )
+import Foreign		( nullPtr )
+import CString		( peekCString )
 
 -----------------------------------------------------------------------------
 
 ghciWelcomeMsg = "\ 
 \   ___         ___ _\n\ 
 \  / _ \\ /\\  /\\/ __(_)\n\ 
-\ / /_\\// /_/ / /  | |      GHC Interactive, version " ++ cProjectVersion ++ ", For Haskell 98.\n\ 
+\ / /_\\// /_/ / /  | |      GHC Interactive, version " ++ cProjectVersion ++ ", for Haskell 98.\n\ 
 \/ /_\\\\/ __  / /___| |      http://www.haskell.org/ghc/\n\ 
 \\\____/\\/ /_/\\____/|_|      Type :? for help.\n"
 
@@ -63,14 +86,17 @@ GLOBAL_VAR(commands, builtin_commands, [(String, String -> GHCi Bool)])
 builtin_commands :: [(String, String -> GHCi Bool)]
 builtin_commands = [
   ("add",	keepGoing addModule),
+  ("browse",    keepGoing browseCmd),
   ("cd",    	keepGoing changeDirectory),
   ("def",	keepGoing defineMacro),
   ("help",	keepGoing help),
   ("?",		keepGoing help),
+  ("info",      keepGoing info),
   ("load",	keepGoing loadModule),
   ("module",	keepGoing setContext),
   ("reload",	keepGoing reloadModule),
-  ("set",	keepGoing setOptions),
+  ("set",	keepGoing setCmd),
+  ("show",	keepGoing showCmd),
   ("type",	keepGoing typeOfExpr),
   ("unset",	keepGoing unsetOptions),
   ("undef",     keepGoing undefineMacro),
@@ -84,111 +110,193 @@ shortHelpText = "use :? for help.\n"
 
 helpText = "\ 
 \ Commands available from the prompt:\n\ 
-\\  
-\   <expr>		evaluate <expr>\n\ 
-\   :add <filename>     add a module to the current set\n\ 
-\   :cd <dir>		change directory to <dir>\n\ 
-\   :help, :?		display this list of commands\n\ 
-\   :load <filename>    load a module (and it 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\ 
-\   :unset <option> ...	unset options\n\ 
-\   :type <expr>	show the type of <expr>\n\ 
-\   :quit		exit GHCi\n\ 
-\   :!<command>		run the shell command <command>\n\ 
+\\
+\   <stmt>		   evaluate/run <stmt>\n\ 
+\   :add <filename> ...    add module(s) to the current target set\n\ 
+\   :browse [*]<module>	   display the names defined by <module>\n\ 
+\   :cd <dir>		   change directory to <dir>\n\ 
+\   :def <cmd> <expr>      define a command :<cmd>\n\ 
+\   :help, :?		   display this list of commands\n\ 
+\   :info [<name> ...]     display information about the given names\n\ 
+\   :load <filename> ...   load module(s) and their dependents\n\ 
+\   :module <mod>	   set the context for expression evaluation to <mod>\n\ 
+\   :reload		   reload the current module set\n\ 
+\\n\ 
+\   :set <option> ...	   set options\n\ 
+\   :set args <arg> ...	   set the arguments returned by System.getArgs\n\ 
+\   :set prog <progname>   set the value returned by System.getProgName\n\ 
+\\n\ 
+\   :show modules	   show the currently loaded modules\n\ 
+\   :show bindings	   show the current bindings made at the prompt\n\ 
+\\n\ 
+\   :type <expr>	   show the type of <expr>\n\ 
+\   :undef <cmd> 	   undefine user-defined command :<cmd>\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\ 
-\    +r			revert top-level expressions after each evaluation\n\ 
 \    -<flags>		most GHC command line flags can also be set here\n\ 
 \                         (eg. -v2, -fglasgow-exts, etc.)\n\ 
 \"
 
-interactiveUI :: CmState -> Maybe FilePath -> [String] -> IO ()
-interactiveUI cmstate mod cmdline_libs = do
+interactiveUI :: CmState -> [FilePath] -> [LibrarySpec] -> IO ()
+interactiveUI cmstate paths cmdline_libs = do
    hFlush stdout
    hSetBuffering stdout NoBuffering
 
+   dflags <- getDynFlags
+
    -- link in the available packages
    pkgs <- getPackageInfo
    initLinker
-   linkPackages cmdline_libs (reverse pkgs)
-
-   (cmstate, ok, mods) <-
-   	case mod of
-	     Nothing  -> return (cmstate, True, [])
-	     Just m -> cmLoadModule cmstate m
-
-#ifndef NO_READLINE
+   linkPackages dflags cmdline_libs pkgs
+
+   (cmstate, maybe_hval) 
+	<- cmCompileExpr cmstate dflags "IO.hSetBuffering IO.stdout IO.NoBuffering Prelude.>> IO.hSetBuffering IO.stderr IO.NoBuffering"
+   case maybe_hval of
+	Just hval -> unsafeCoerce# hval :: IO ()
+	_ -> panic "interactiveUI:buffering"
+
+   (cmstate, maybe_hval)
+	<- cmCompileExpr cmstate dflags "IO.hFlush IO.stderr"
+   case maybe_hval of
+	Just hval -> writeIORef flush_stderr (unsafeCoerce# hval :: IO ())
+	_ -> panic "interactiveUI:stderr"
+
+   (cmstate, maybe_hval) 
+	<- cmCompileExpr cmstate dflags "IO.hFlush IO.stdout"
+   case maybe_hval of
+	Just hval -> writeIORef flush_stdout (unsafeCoerce# hval :: IO ())
+	_ -> panic "interactiveUI:stdout"
+
+	-- We don't want the cmd line to buffer any input that might be
+	-- intended for the program, so unbuffer stdin.
+   hSetBuffering stdin  NoBuffering
+
+	-- initial context is just the Prelude
+   cmstate <- cmSetContext cmstate dflags [] ["Prelude"]
+
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
    Readline.initialize
 #endif
 
-   prel <- moduleNameToModule defaultCurrentModuleName
-   writeIORef defaultCurrentModule prel
+   startGHCi (runGHCi paths dflags) 
+	GHCiState{ progname = "<interactive>",
+		   args = [],
+		   targets = paths,
+		   cmstate = cmstate,
+		   options = [] }
 
-   dflags <- getDynFlags
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+   Readline.resetTerminal Nothing
+#endif
 
-   (cmstate, maybe_stuff) <- cmGetExpr cmstate dflags False prel 
-		  		"PrelHandle.hFlush PrelHandle.stdout"
-   case maybe_stuff of
-	Nothing -> return ()
-	Just (hv,_,_) -> writeIORef flush_stdout hv
-   
-   (cmstate, maybe_stuff) <- cmGetExpr cmstate dflags False prel 
-		  		"PrelHandle.hFlush PrelHandle.stdout"
-   case maybe_stuff of
-	Nothing -> return ()
-	Just (hv,_,_) -> writeIORef flush_stderr hv
-   
-   let this_mod = case mods of 
-	  	      []   -> prel
-  	  	      m:ms -> m
-
-   (unGHCi runGHCi) GHCiState{ modules = mods,
-			      current_module = this_mod,
-	  	              target = mod,
-			      cmstate = cmstate,
-			      options = [ShowTiming],
-                              last_expr = Nothing}
    return ()
 
 
-runGHCi :: GHCi ()
-runGHCi = do
-  -- read in ./.ghci
-  dot_ghci <- io (IO.try (openFile "./.ghci" ReadMode))
-  case dot_ghci of
-	Left e -> return ()
-	Right hdl -> fileLoop hdl False
-  
-  -- read in ~/.ghci
-  home <- io (IO.try (getEnv "HOME"))
-  case home of
-   Left e  -> return ()
-   Right dir -> do
-  	dot_ghci <- io (IO.try (openFile (dir ++ "/.ghci") ReadMode))
-	case dot_ghci of
-	   Left e -> return ()
-	   Right hdl -> fileLoop hdl False
+runGHCi :: [FilePath] -> DynFlags -> GHCi ()
+runGHCi paths dflags = do
+  read_dot_files <- io (readIORef v_Read_DotGHCi)
+
+  when (read_dot_files) $ 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
+    
+  when (read_dot_files) $ do
+    -- 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)
+  	     when ok $ do
+  	       either_hdl <- io (IO.try (openFile file ReadMode))
+  	       case either_hdl of
+  		  Left e    -> return ()
+  		  Right hdl -> fileLoop hdl False
+
+  -- perform a :load for files given on the GHCi command line
+  when (not (null paths)) $
+     ghciHandle showException $
+	loadModule (unwords paths)
+
+  -- enter the interactive loop
+  is_tty <- io (hIsTerminalDevice stdin)
+  interactiveLoop is_tty
+
+  -- and finally, exit
+  io $ do when (verbosity dflags > 0) $ putStrLn "Leaving GHCi."
+
+
+interactiveLoop is_tty = do
+  -- ignore ^C exceptions caught here
+  ghciHandleDyn (\e -> case e of 
+			Interrupted -> ghciUnblock (interactiveLoop is_tty)
+			_other      -> return ()) $ do
 
   -- read commands from stdin
-#ifndef NO_READLINE
-  readlineLoop
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+  if (is_tty) 
+	then readlineLoop
+	else fileLoop stdin False  -- turn off prompt for non-TTY input
 #else
   fileLoop stdin True
 #endif
 
-  -- 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 . is owned by the current user
+-- and isn'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 =
+  DriverUtil.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
 
 fileLoop :: Handle -> Bool -> GHCi ()
 fileLoop hdl prompt = do
-   st <- getGHCiState
-   when prompt (io (hPutStr hdl (moduleUserString (current_module st) ++ "> ")))
+   cmstate <- getCmState
+   (mod,imports) <- io (cmGetContext cmstate)
+   when prompt (io (putStr (mkPrompt mod imports)))
    l <- io (IO.try (hGetLine hdl))
    case l of
 	Left e | isEOFError e -> return ()
@@ -202,17 +310,21 @@ fileLoop hdl prompt = do
 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
 
-#ifndef NO_READLINE
+mkPrompt toplevs exports
+   = concat (intersperse " " (toplevs ++ map ('*':) exports)) ++ "> "
+
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
 readlineLoop :: GHCi ()
 readlineLoop = do
-   st <- getGHCiState
-   l <- io (readline (moduleUserString (current_module st) ++ "> "))
+   cmstate <- getCmState
+   (mod,imports) <- io (cmGetContext cmstate)
+   io yield
+   l <- io (readline (mkPrompt mod imports))
    case l of
 	Nothing -> return ()
 	Just l  ->
@@ -228,71 +340,68 @@ readlineLoop = do
 -- and carries on.
 runCommand :: String -> GHCi Bool
 runCommand c = 
-  ghciHandle ( \exception -> 
-	(case exception of
-	   DynException dyn -> 
-	      case fromDynamic dyn of
-		Nothing -> io (putStrLn ("*** Exception: (unknown)"))
-		Just ghc_ex -> 
-		  case ghc_ex of
-		    PhaseFailed phase code ->
-			io ( putStrLn ("Phase " ++ phase ++ " failed (code "
-				        ++ show code ++ ")"))
-		    Interrupted -> io (putStrLn "Interrupted.")
-		    other -> io (putStrLn (show (ghc_ex :: GhcException)))
-
-	   other -> io (putStrLn ("*** Exception: " ++ show exception))
-
-	) >> return False
-     ) $
-
-   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 Interrupted      -> io (putStrLn "Interrupted.")
+    Just (CmdLineError s) -> io (putStrLn s)	 -- omit the location for CmdLineError
+    Just ph@PhaseFailed{} -> io (putStrLn (showGhcException ph "")) -- ditto
+    Just other_ghc_ex     -> io (print other_ghc_ex)
+
+showException other_exception
+  = io (putStrLn ("*** Exception: " ++ show other_exception))
 
 doCommand (':' : command) = specialCommand command
-doCommand ('-':'-':_) = return False	-- comments, useful in scripts
-doCommand expr
-   = do expr_expanded <- expandExpr expr
-        -- io (putStrLn ( "Before: " ++ expr ++ "\nAfter:  " ++ expr_expanded))
-        expr_ok <- timeIt (do stuff <- evalExpr expr_expanded
-			      finishEvalExpr expr_expanded stuff)
-        when expr_ok (rememberExpr expr_expanded)
+doCommand stmt
+   = do timeIt (do nms <- runStmt stmt; finishEvalExpr nms)
         return False
 
--- Returns True if the expr was successfully parsed, renamed and
--- typechecked.
-evalExpr :: String -> GHCi Bool
-evalExpr expr
- | null (filter (not.isSpace) expr)
- = return False
+runStmt :: String -> GHCi [Name]
+runStmt stmt
+ | null (filter (not.isSpace) stmt) = return []
  | otherwise
  = do st <- getGHCiState
-      dflags <- io (getDynFlags)
-      (new_cmstate, maybe_stuff) <- 
-      	 io (cmGetExpr (cmstate st) dflags True (current_module st) expr)
+      dflags <- io getDynFlags
+      let dflags' = dopt_unset dflags Opt_WarnUnusedBinds
+      (new_cmstate, result) <- 
+	io $ withProgName (progname st) $ withArgs (args st) $
+	cmRunStmt (cmstate st) dflags' stmt
       setGHCiState st{cmstate = new_cmstate}
-      case maybe_stuff of
-      	 Nothing -> return False
-      	 Just (hv, unqual, ty) -> 
-		do io (cmRunExpr hv)
-		   return True
+      case result of
+	CmRunFailed      -> return []
+	CmRunException e -> showException e >> return []
+	CmRunOk names    -> return names
 
 -- possibly print the type and revert CAFs after evaluating an expression
-finishEvalExpr _ False = return False
-finishEvalExpr expr True
+finishEvalExpr names
  = do b <- isOptionSet ShowType
-	-- re-typecheck, don't wrap with print this time
-      when b (io (putStr ":: ") >> typeOfExpr expr)
+      cmstate <- getCmState
+      when b (mapM_ (showTypeOfName cmstate) 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
-     	     cmRunExpr flush_so
-     	     flush_se <- readIORef flush_stdout
-     	     cmRunExpr flush_se
+   = io $ do Monad.join (readIORef flush_stdout)
+     	     Monad.join (readIORef flush_stderr)
+             return ()
 
 specialCommand :: String -> GHCi Bool
 specialCommand ('!':str) = shellEscape (dropWhile isSpace str)
@@ -308,7 +417,7 @@ specialCommand str = do
 	         	     	       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
@@ -316,36 +425,83 @@ noArgs c = io (hPutStrLn stdout ("command `:" ++ c ++ "' takes no arguments"))
 help :: String -> GHCi ()
 help _ = io (putStr helpText)
 
-addModule :: String -> GHCi ()
-addModule _ = throwDyn (OtherError ":add not implemented")
-
-setContext :: String -> GHCi ()
-setContext ""
-  = throwDyn (OtherError "syntax: `:m <module>'")
-setContext m | not (isUpper (head m)) || not (all isAlphaNum (tail m))
-  = throwDyn (OtherError ("strange looking module name: `" ++ m ++ "'"))
-setContext str
-  = do st <- getGHCiState
-
-       let mn = mkModuleName str
-       m <- case [ m | m <- modules st, moduleName m == mn ] of
-		(m:_) -> return m
-		[]    -> io (moduleNameToModule mn)
-
-       if (isHomeModule m && m `notElem` modules st)
-	  then throwDyn (OtherError (showSDoc (quotes (ppr (moduleName m))
-				<+> text "is not currently loaded, use :load")))
-	  else setGHCiState st{current_module = m}
+info :: String -> GHCi ()
+info "" = throwDyn (CmdLineError "syntax: `:i <thing-you-want-info-about>'")
+info s = do
+  let names = words s
+  init_cms <- getCmState
+  dflags <- io getDynFlags
+  let 
+    infoThings cms [] = return cms
+    infoThings cms (name:names) = do
+      (cms, stuff) <- io (cmInfoThing cms dflags name)
+      io (putStrLn (showSDocForUser unqual (
+	    vcat (intersperse (text "") (map showThing stuff))))
+         )
+      infoThings cms names
+
+    unqual = cmGetPrintUnqual init_cms
+
+    showThing (ty_thing, fixity) 
+	= vcat [ text "-- " <> showTyThing ty_thing, 
+		 showFixity fixity (getName ty_thing),
+	         ppr (ifaceTyThing ty_thing) ]
+
+    showFixity fix name
+	| fix == defaultFixity = empty
+	| otherwise            = ppr fix <+> 
+				 (if isSymOcc (nameOccName name)
+					then ppr name
+					else char '`' <> ppr name <> char '`')
+
+    showTyThing (AClass cl)
+       = hcat [ppr cl, text " is a class", showSrcLoc (className cl)]
+    showTyThing (ATyCon ty)
+       | isPrimTyCon ty
+       = hcat [ppr ty, text " is a primitive type constructor"]
+       | otherwise
+       = hcat [ppr ty, text " is a type constructor", showSrcLoc (tyConName ty)]
+    showTyThing (AnId   id)
+       = hcat [ppr id, text " is a ", idDescr id, showSrcLoc (idName id)]
+
+    idDescr id
+       | isRecordSelector id = 
+		case tyConClass_maybe (fieldLabelTyCon (
+				recordSelectorFieldLabel id)) of
+			Nothing -> text "record selector"
+			Just c  -> text "method in class " <> ppr c
+       | isDataConWrapId id  = text "data constructor"
+       | otherwise           = text "variable"
+
+	-- also print out the source location for home things
+    showSrcLoc name
+	| isHomePackageName name && isGoodSrcLoc loc
+	= hsep [ text ", defined at", ppr loc ]
+	| otherwise
+	= empty
+	where loc = nameSrcLoc name
+
+  cms <- infoThings init_cms names
+  setCmState cms
+  return ()
 
-moduleNameToModule :: ModuleName -> IO Module
-moduleNameToModule mn
- = do maybe_stuff <- findModule mn
-      case maybe_stuff of
-	Nothing -> throwDyn (OtherError ("can't find module `"
-				    ++ moduleNameUserString mn ++ "'"))
-	Just (m,_) -> return m
+addModule :: String -> GHCi ()
+addModule str = do
+  let files = words str
+  state <- getGHCiState
+  dflags <- io (getDynFlags)
+  io (revertCAFs)			-- always revert CAFs on load/add.
+  let new_targets = files ++ targets state 
+  graph <- io (cmDepAnal (cmstate state) dflags new_targets)
+  (cmstate1, ok, mods) <- io (cmLoadModules (cmstate state) dflags graph)
+  setGHCiState state{ cmstate = cmstate1, targets = new_targets }
+  setContextAfterLoad mods
+  modulesLoadedMsg ok mods dflags
 
 changeDirectory :: String -> GHCi ()
+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 ()
@@ -353,11 +509,11 @@ defineMacro s = do
   let (macro_name, definition) = break isSpace s
   cmds <- io (readIORef commands)
   if (null macro_name) 
-	then throwDyn (OtherError "invalid macro name") 
+	then throwDyn (CmdLineError "invalid macro name") 
 	else do
   if (macro_name `elem` map fst cmds) 
-	then throwDyn (OtherError 
-		("command `" ++ macro_name ++ "' already defined"))
+	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
@@ -365,16 +521,14 @@ defineMacro s = do
   let new_expr = '(' : definition ++ ") :: String -> IO String"
 
   -- compile the expression
-  st <- getGHCiState
-  dflags <- io (getDynFlags)
-  (new_cmstate, maybe_stuff) <- 
-      	 io (cmGetExpr (cmstate st) dflags False (current_module st) new_expr)
-  setGHCiState st{cmstate = new_cmstate}
-  case maybe_stuff of
+  cms <- getCmState
+  dflags <- io getDynFlags
+  (new_cmstate, maybe_hv) <- io (cmCompileExpr cms dflags new_expr)
+  setCmState new_cmstate
+  case maybe_hv of
      Nothing -> return ()
-     Just (hv, unqual, ty) 
-	-> io (writeIORef commands 
-		 ((macro_name, keepGoing (runMacro hv)) : cmds))
+     Just hv -> io (writeIORef commands --
+		    ((macro_name, keepGoing (runMacro hv)) : cmds))
 
 runMacro :: HValue{-String -> IO String-} -> String -> GHCi ()
 runMacro fun s = do
@@ -385,75 +539,88 @@ undefineMacro :: String -> GHCi ()
 undefineMacro macro_name = do
   cmds <- io (readIORef commands)
   if (macro_name `elem` map fst builtin_commands) 
-	then throwDyn (OtherError
+	then throwDyn (CmdLineError
 		("command `" ++ macro_name ++ "' cannot be undefined"))
 	else do
   if (macro_name `notElem` map fst cmds) 
-	then throwDyn (OtherError 
+	then throwDyn (CmdLineError 
 		("command `" ++ macro_name ++ "' not defined"))
 	else do
   io (writeIORef commands (filter ((/= macro_name) . fst) cmds))
 
+
 loadModule :: String -> GHCi ()
-loadModule path = timeIt (loadModule' path)
+loadModule str = timeIt (loadModule' str)
+
+loadModule' str = do
+  let files = words str
+  state <- getGHCiState
+  dflags <- io getDynFlags
+
+  -- do the dependency anal first, so that if it fails we don't throw
+  -- away the current set of modules.
+  graph <- io (cmDepAnal (cmstate state) dflags files)
 
-loadModule' path = do
+  -- Dependency anal ok, now unload everything
+  cmstate1 <- io (cmUnload (cmstate state) dflags)
+  setGHCiState state{ cmstate = cmstate1, targets = [] }
+
+  io (revertCAFs)  -- always revert CAFs on load.
+  (cmstate2, ok, mods) <- io (cmLoadModules cmstate1 dflags graph)
+  setGHCiState state{ cmstate = cmstate2, targets = files }
+
+  setContextAfterLoad mods
+  modulesLoadedMsg ok mods dflags
+
+
+reloadModule :: String -> GHCi ()
+reloadModule "" = do
   state <- getGHCiState
-  cmstate1 <- io (cmUnload (cmstate state))
-  io (revertCAFs)			-- always revert CAFs on load.
-  (cmstate2, ok, mods) <- io (cmLoadModule cmstate1 path)
-
-  def_mod <- io (readIORef defaultCurrentModule)
-
-  let new_state = state{
-  			cmstate = cmstate2,
-			modules = mods,
-			current_module = case mods of 
-					   [] -> def_mod
-					   xs -> head xs,
-			target = Just path
-		   }
-  setGHCiState new_state
-
-  let mod_commas 
+  dflags <- io getDynFlags
+  case targets state of
+   [] -> io (putStr "no current target\n")
+   paths -> do
+	-- do the dependency anal first, so that if it fails we don't throw
+	-- away the current set of modules.
+	graph <- io (cmDepAnal (cmstate state) dflags paths)
+
+	io (revertCAFs)		-- always revert CAFs on reload.
+	(cmstate1, ok, mods) 
+		<- io (cmLoadModules (cmstate state) dflags graph)
+        setGHCiState state{ cmstate=cmstate1 }
+	setContextAfterLoad mods
+	modulesLoadedMsg ok mods dflags
+
+reloadModule _ = noArgs ":reload"
+
+setContextAfterLoad [] = setContext prel
+setContextAfterLoad (m:_) = do
+  cmstate <- getCmState
+  b <- io (cmModuleIsInterpreted cmstate m)
+  if b then setContext m else setContext ('*':m)
+
+modulesLoadedMsg ok mods dflags =
+  when (verbosity dflags > 0) $ do
+   let mod_commas 
 	| null mods = text "none."
 	| otherwise = hsep (
-	    punctuate comma (map (text.moduleUserString) mods)) <> text "."
-  case ok of
+	    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 io (revertCAFs)		-- always revert CAFs on reload.
-	    (new_cmstate, ok, mods) <- io (cmLoadModule (cmstate state) path)
-	    def_mod <- io (readIORef defaultCurrentModule)
-            setGHCiState 
-               state{cmstate=new_cmstate,
-                     modules = mods,
-                     current_module = case mods of 
-                                         [] -> def_mod
-                                         xs -> head xs
-                    }
-
-reloadModule _ = noArgs ":reload"
 
 typeOfExpr :: String -> GHCi ()
 typeOfExpr str 
-  = do st <- getGHCiState
-       dflags <- io (getDynFlags)
-       (new_cmstate, maybe_ty) <- io (cmGetExpr (cmstate st) dflags False
-					 (current_module st) str)
-       setGHCiState st{cmstate = new_cmstate}
-       case maybe_ty of
-	 Nothing -> return ()
-	 Just (_, unqual, ty) -> io (printForUser stdout unqual (ppr ty)) 
+  = do cms <- getCmState
+       dflags <- io getDynFlags
+       (new_cmstate, maybe_tystr) <- io (cmTypeOfExpr cms dflags str)
+       setCmState new_cmstate
+       case maybe_tystr of
+	  Nothing    -> return ()
+	  Just tystr -> io (putStrLn tystr)
 
 quit :: String -> GHCi Bool
 quit _ = return True
@@ -461,6 +628,131 @@ quit _ = return True
 shellEscape :: String -> GHCi Bool
 shellEscape str = io (system str >> return False)
 
+-----------------------------------------------------------------------------
+-- Browing a module's contents
+
+browseCmd :: String -> GHCi ()
+browseCmd m = 
+  case words m of
+    ['*':m] | looksLikeModuleName m -> browseModule m True
+    [m]     | looksLikeModuleName m -> browseModule m False
+    _ -> throwDyn (CmdLineError "syntax:  :browse <module>")
+
+browseModule m exports_only = do
+  cms <- getCmState
+  dflags <- io getDynFlags
+
+  is_interpreted <- io (cmModuleIsInterpreted cms m)
+  when (not is_interpreted && not exports_only) $
+	throwDyn (CmdLineError ("module `" ++ m ++ "' is not interpreted"))
+
+  -- temporarily set the context to the module we're interested in,
+  -- just so we can get an appropriate PrintUnqualified
+  (as,bs) <- io (cmGetContext cms)
+  cms1 <- io (if exports_only then cmSetContext cms dflags [] [prel,m]
+			      else cmSetContext cms dflags [m] [])
+  cms2 <- io (cmSetContext cms1 dflags as bs)
+
+  (cms3, things) <- io (cmBrowseModule cms2 dflags m exports_only)
+
+  setCmState cms3
+
+  let unqual = cmGetPrintUnqual cms1 -- NOTE: cms1 with the new context
+
+      things' = filter wantToSee things
+
+      wantToSee (AnId id) = not (isDataConId id || isDataConWrapId id)
+      wantToSee _ = True
+
+      thing_names = map getName things
+
+      thingDecl thing@(AnId id)  = ifaceTyThing thing
+
+      thingDecl thing@(AClass c) =
+        let rn_decl = ifaceTyThing thing in
+	case rn_decl of
+	  ClassDecl { tcdSigs = cons } -> 
+		rn_decl{ tcdSigs = filter methodIsVisible cons }
+	  other -> other
+        where
+           methodIsVisible (ClassOpSig n _ _ _) = n `elem` thing_names
+
+      thingDecl thing@(ATyCon t) =
+        let rn_decl = ifaceTyThing thing in
+	case rn_decl of
+	  TyData { tcdCons = DataCons cons } -> 
+		rn_decl{ tcdCons = DataCons (filter conIsVisible cons) }
+	  other -> other
+        where
+	  conIsVisible (ConDecl n _ _ _ _ _) = n `elem` thing_names
+
+  io (putStrLn (showSDocForUser unqual (
+   	 vcat (map (ppr . thingDecl) things')))
+   )
+
+  where
+
+-----------------------------------------------------------------------------
+-- Setting the module context
+
+setContext str
+  | all sensible mods = fn mods
+  | otherwise = throwDyn (CmdLineError "syntax:  :module [+/-] [*]M1 ... [*]Mn")
+  where
+    (fn, mods) = case str of 
+			'+':stuff -> (addToContext,      words stuff)
+			'-':stuff -> (removeFromContext, words stuff)
+			stuff     -> (newContext,        words stuff) 
+
+    sensible ('*':m) = looksLikeModuleName m
+    sensible m       = looksLikeModuleName m
+
+newContext mods = do
+  cms <- getCmState
+  dflags <- io getDynFlags
+  (as,bs) <- separate cms mods [] []
+  let bs' = if null as && prel `notElem` bs then prel:bs else bs
+  cms' <- io (cmSetContext cms dflags as bs')
+  setCmState cms'
+
+separate cmstate []           as bs = return (as,bs)
+separate cmstate (('*':m):ms) as bs = separate cmstate ms as (m:bs)
+separate cmstate (m:ms)       as bs = do 
+   b <- io (cmModuleIsInterpreted cmstate m)
+   if b then separate cmstate ms (m:as) bs
+   	else throwDyn (CmdLineError ("module `" ++ m ++ "' is not interpreted"))
+	
+prel = "Prelude"
+
+
+addToContext mods = do
+  cms <- getCmState
+  dflags <- io getDynFlags
+  (as,bs) <- io (cmGetContext cms)
+
+  (as',bs') <- separate cms mods [] []
+
+  let as_to_add = as' \\ (as ++ bs)
+      bs_to_add = bs' \\ (as ++ bs)
+
+  cms' <- io (cmSetContext cms dflags 
+			(as ++ as_to_add) (bs ++ bs_to_add))
+  setCmState cms'
+
+
+removeFromContext mods = do
+  cms <- getCmState
+  dflags <- io getDynFlags
+  (as,bs) <- io (cmGetContext cms)
+
+  (as_to_remove,bs_to_remove) <- separate cms mods [] []
+
+  let as' = as \\ (as_to_remove ++ bs_to_remove)
+      bs' = bs \\ (as_to_remove ++ bs_to_remove)
+
+  cms' <- io (cmSetContext cms dflags as' bs')
+  setCmState cms'
+
 ----------------------------------------------------------------------------
 -- Code for `:set'
 
@@ -471,8 +763,8 @@ shellEscape str = io (system str >> return False)
 -- This is pretty fragile: most options won't work as expected.  ToDo:
 -- figure out which ones & disallow them.
 
-setOptions :: String -> GHCi ()
-setOptions ""
+setCmd :: String -> GHCi ()
+setCmd ""
   = do st <- getGHCiState
        let opts = options st
        io $ putStrLn (showSDoc (
@@ -481,34 +773,47 @@ setOptions ""
    		   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 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
+setCmd str
+  = case words str of
+	("args":args) -> setArgs args
+	("prog":prog) -> setProg prog
+	wds -> setOptions wds
 
-       mapM setOpt plus_opts
-
-       -- now, the GHC flags
-       io (do -- first, static flags
-	      leftovers <- processArgs static_flags minus_opts []
-
-	      -- then, dynamic flags
-	      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
+setArgs args = do
+  st <- getGHCiState
+  setGHCiState st{ args = args }
 
-              if (not (null leftovers))
-		 then throwDyn (OtherError ("unrecognised flags: " ++ 
+setProg [prog] = do
+  st <- getGHCiState
+  setGHCiState st{ progname = prog }
+setProg _ = do
+  io (hPutStrLn stderr "syntax: :set prog <progname>")
+
+setOptions wds =
+   do -- first, deal with the GHCi opts (+s, +t, etc.)
+      let (plus_opts, minus_opts)  = partition isPlus wds
+      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 ()
-         )
+		else return ()
+
 
 unsetOptions :: String -> GHCi ()
 unsetOptions str
@@ -525,7 +830,7 @@ unsetOptions str
  
        -- can't do GHC flags for now
        if (not (null minus_opts))
-	  then throwDyn (OtherError "can't unset GHC command-line flags")
+	  then throwDyn (CmdLineError "can't unset GHC command-line flags")
 	  else return ()
 
 isMinus ('-':s) = True
@@ -555,55 +860,61 @@ optToStr ShowTiming = "s"
 optToStr ShowType   = "t"
 optToStr RevertCAFs = "r"
 
------------------------------------------------------------------------------
--- Code to do last-expression-entered stuff.  (a.k.a the $$ facility)
+newPackages new_pkgs = do
+  state <- getGHCiState
+  dflags <- io getDynFlags
+  cmstate1 <- io (cmUnload (cmstate state) dflags)
+  setGHCiState state{ cmstate = cmstate1, targets = [] }
 
--- Take a string and replace $$s in it with the last expr, if any.
-expandExpr :: String -> GHCi String
-expandExpr str
-   = do mle <- getLastExpr
-        return (outside mle str)
-     where
-        outside mle ('$':'$':cs)
-           = case mle of
-                Just le -> " (" ++ le ++ ") " ++ outside mle cs
-                Nothing -> outside mle cs
-
-        outside mle []           = []
-        outside mle ('"':str)    = '"' : inside2 mle str   -- "
-        outside mle ('\'':str)   = '\'' : inside1 mle str   -- '
-        outside mle (c:cs)       = c : outside mle cs
-
-        inside2 mle ('"':cs)  = '"' : outside mle cs   -- "
-        inside2 mle (c:cs)    = c : inside2 mle cs
-        inside2 mle []        = []
-
-        inside1 mle ('\'':cs) = '\'': outside mle cs
-        inside1 mle (c:cs)    = c : inside1 mle cs
-        inside1 mle []        = []
-
-
-rememberExpr :: String -> GHCi ()
-rememberExpr str
-   = do let cleaned = (clean . reverse . clean . reverse) str
-        let forget_me_not | null cleaned = Nothing
-                          | otherwise    = Just cleaned
-        setLastExpr forget_me_not
-     where
-        clean = dropWhile isSpace
+  io $ do
+    pkgs <- getPackageInfo
+    flushPackageCache pkgs
+   
+    new_pkg_info <- getPackageDetails new_pkgs
+    mapM_ (linkPackage dflags) (reverse new_pkg_info)
 
+-----------------------------------------------------------------------------
+-- code for `:show'
+
+showCmd str =
+  case words str of
+	["modules" ] -> showModules
+	["bindings"] -> showBindings
+	_ -> throwDyn (CmdLineError "syntax:  :show [modules|bindings]")
+
+showModules = do
+  cms <- getCmState
+  let mg = cmGetModuleGraph cms
+      ls = cmGetLinkables   cms
+      maybe_linkables = map (findModuleLinkable_maybe ls) 
+				(map (moduleName.ms_mod) mg)
+  zipWithM showModule mg maybe_linkables
+  return ()
+
+showModule :: ModSummary -> Maybe Linkable -> GHCi ()
+showModule m (Just l) = do
+  io (putStrLn (showModMsg (isObjectLinkable l) (ms_mod m) (ms_location m)))
+showModule _ Nothing = panic "missing linkable"
+
+showBindings = do
+  cms <- getCmState
+  let
+	unqual = cmGetPrintUnqual cms
+	showBinding b = putStrLn (showSDocForUser unqual (ppr (ifaceTyThing b)))
+
+  io (mapM showBinding (cmGetBindings cms))
+  return ()
 
 -----------------------------------------------------------------------------
 -- GHCi monad
 
 data GHCiState = GHCiState
      { 
-	modules	       :: [Module],
-	current_module :: Module,
-	target         :: Maybe FilePath,
+	progname       :: String,
+	args	       :: [String],
+	targets        :: [FilePath],
 	cmstate        :: CmState,
-	options        :: [GHCiOption],
-        last_expr      :: Maybe String
+	options        :: [GHCiOption]
      }
 
 data GHCiOption 
@@ -612,20 +923,28 @@ data GHCiOption
 	| RevertCAFs		-- revert CAFs after every evaluation
 	deriving Eq
 
-defaultCurrentModuleName = mkModuleName "Prelude"
-GLOBAL_VAR(defaultCurrentModule, error "no defaultCurrentModule", Module)
+GLOBAL_VAR(flush_stdout, error "no flush_stdout", IO ())
+GLOBAL_VAR(flush_stderr, error "no flush_stdout", IO ())
 
-GLOBAL_VAR(flush_stdout, error "no flush_stdout", HValue)
-GLOBAL_VAR(flush_stderr, error "no flush_stdout", HValue)
+newtype GHCi a = GHCi { unGHCi :: IORef GHCiState -> IO a }
 
-newtype GHCi a = GHCi { unGHCi :: GHCiState -> IO (GHCiState, 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 $ \s -> return (s,s)
-setGHCiState s = GHCi $ \_ -> return (s,())
+ghciHandleDyn :: Typeable t => (t -> GHCi a) -> GHCi a -> GHCi a
+ghciHandleDyn h (GHCi m) = GHCi $ \s -> 
+   Exception.catchDyn (m s) (\e -> unGHCi (h e) s)
+
+getGHCiState   = GHCi $ \r -> readIORef r
+setGHCiState s = GHCi $ \r -> writeIORef r s
+
+-- for convenience...
+getCmState = getGHCiState >>= return . cmstate
+setCmState cms = do s <- getGHCiState; setGHCiState s{cmstate=cms}
 
 isOptionSet :: GHCiOption -> GHCi Bool
 isOptionSet opt
@@ -642,15 +961,8 @@ unsetOption opt
  = do st <- getGHCiState
       setGHCiState (st{ options = filter (/= opt) (options st) })
 
-getLastExpr :: GHCi (Maybe String)
-getLastExpr
- = do st <- getGHCiState ; return (last_expr st)
-
-setLastExpr :: Maybe String -> GHCi ()
-setLastExpr last_expr
- = do st <- getGHCiState ; setGHCiState (st{last_expr = last_expr})
-
-io m = GHCi $ \s -> m >>= \a -> return (s,a)
+io :: IO a -> GHCi a
+io m = GHCi { unGHCi = \s -> m >>= return }
 
 -----------------------------------------------------------------------------
 -- recursive exception handlers
@@ -670,82 +982,137 @@ ghciUnblock (GHCi a) = GHCi $ \s -> Exception.unblock (a s)
 -----------------------------------------------------------------------------
 -- package loader
 
-linkPackages :: [String] -> [Package] -> IO ()
-linkPackages cmdline_libs pkgs
-   = do mapM preloadLib cmdline_libs
-        mapM_ linkPackage pkgs
+-- 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 :: DynFlags -> [LibrarySpec] -> [PackageConfig] -> IO ()
+linkPackages dflags cmdline_lib_specs pkgs
+   = do mapM_ (linkPackage dflags) (reverse pkgs)
+        lib_paths <- readIORef v_Library_paths
+        mapM_ (preloadLib dflags lib_paths) cmdline_lib_specs
+	if (null cmdline_lib_specs)
+	   then return ()
+	   else do maybePutStr dflags "final link ... "
+		   ok <- resolveObjs
+		   if ok then maybePutStrLn dflags "done."
+	      		 else throwDyn (InstallationError 
+                                          "linking extra libraries/objects failed")
      where
-        preloadLib orig_name
-           = do putStr ("Loading object " ++ orig_name ++ " ... ")
-                case classify orig_name of
+        preloadLib :: DynFlags -> [String] -> LibrarySpec -> IO ()
+        preloadLib dflags lib_paths lib_spec
+           = do maybePutStr dflags ("Loading object " ++ showLS lib_spec ++ " ... ")
+                case lib_spec of
                    Left static_ish
-                      -> do b <- doesFileExist static_ish
-                            if    not b
-                             then do putStr "not found.\n"
-                                     croak
-                             else do loadObj static_ish
-                                     putStr "done.\n"
+                      -> do b <- preload_static lib_paths static_ish
+                            maybePutStrLn dflags (if b  then "done." 
+							else "not found")
                    Right dll_unadorned
-                      -> do dll_ok <- addDLL dll_unadorned
-                            if    dll_ok
-                             then putStr "done.\n"
-                             else do putStr "not found.\n"
-                                     croak
-
-        croak = throwDyn (OtherError "user specified .o/.so/.DLL cannot be found.")
-
-        classify a_lib
-           = let a_libr = reverse a_lib
-             in  
-             case map toLower a_libr of
-                ('o':'.':_) 
-                   -> Left a_lib
-                ('o':'s':'.':_) 
-                   -> (Right . zap_leading_lib
-                             . reverse . drop 3 . reverse) a_lib
-                ('l':'l':'d':'.':_) 
-                   -> (Right . reverse . drop 4 . reverse) a_lib
-                other 
-                   -> -- Main.beginInteractive should not have let this through
-                      pprPanic "linkPackages" (text (show a_lib))
-                      
-        zap_leading_lib str
-           = if take 3 str == "lib" then drop 3 str else str
-
-
-linkPackage :: Package -> IO ()
--- ignore rts and gmp for now (ToDo; better?)
-linkPackage pkg 
-   | name pkg `elem` ["rts", "gmp"] 
-   = return ()
+                      -> -- 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 maybe_errstr <- preload_dynamic (lib_paths++[""]) 
+                                                            dll_unadorned
+                            case maybe_errstr of
+                               Nothing -> return ()
+                               Just mm -> preloadFailed mm lib_paths lib_spec
+                            maybePutStrLn dflags "done"
+
+        preloadFailed :: String -> [String] -> LibrarySpec -> IO ()
+        preloadFailed sys_errmsg paths spec
+           = do maybePutStr dflags
+		       ("failed.\nDynamic linker error message was:\n   " 
+                        ++ sys_errmsg  ++ "\nWhilst trying to load:  " 
+                        ++ showLS spec ++ "\nDirectories to search are:\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
+
+        -- return Nothing == success, else Just error message from addDLL
+        preload_dynamic [] name
+           = return Nothing
+        preload_dynamic (path:paths) rootname
+           = do -- addDLL returns NULL on success
+                maybe_errmsg <- addDLL path rootname
+                if    maybe_errmsg == nullPtr
+                 then preload_dynamic paths rootname
+                 else do str <- peekCString maybe_errmsg
+                         return (Just str)
+
+        give_up 
+           = (throwDyn . CmdLineError)
+                "user specified .o/.so/.DLL could not be loaded."
+
+-- Packages that don't need loading, because the compiler shares them with
+-- the interpreted program.
+dont_load_these = [ "gmp", "rts" ]
+
+-- Packages that are already linked into GHCi.  For mingw32, we only
+-- skip gmp and rts, since std and after need to load the msvcrt.dll
+-- library which std depends on.
+loaded_in_ghci
+#          ifndef mingw32_TARGET_OS
+           = [ "std", "concurrent", "posix", "text", "util" ]
+#          else
+	   = [ ]
+#          endif
+
+linkPackage :: DynFlags -> PackageConfig -> IO ()
+linkPackage dflags pkg
+   | name pkg `elem` dont_load_these = return ()
    | otherwise
-   = do putStr ("Loading package " ++ name pkg ++ " ... ")
+   = do 
         -- 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
-        let sos_first = filter isRight classifieds 
-                        ++ filter (not.isRight) classifieds
+
+	-- 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 | name pkg `elem` loaded_in_ghci = obj_libs
+		      | otherwise      		       = so_libs ++ obj_libs
+
+	maybePutStr dflags ("Loading package " ++ name pkg ++ " ... ")
         mapM loadClassified sos_first
-        putStr "linking ... "
-        resolveObjs
-        putStrLn "done."
+        maybePutStr dflags "linking ... "
+        ok <- resolveObjs
+	if ok then maybePutStrLn dflags "done."
+	      else panic ("can't load package `" ++ name pkg ++ "'")
      where
         isRight (Right _) = True
         isRight (Left _)  = False
 
-loadClassified :: Either FilePath String -> IO ()
+loadClassified :: LibrarySpec -> IO ()
 loadClassified (Left obj_absolute_filename)
    = do loadObj obj_absolute_filename
 loadClassified (Right dll_unadorned)
-   = do dll_ok <- addDLL dll_unadorned
-        if dll_ok
+   = do maybe_errmsg <- addDLL "" dll_unadorned -- doesn't seem right to me
+        if    maybe_errmsg == nullPtr
          then return ()
-         else throwDyn (OtherError ("can't find .o or .so/.DLL for: " 
-                                    ++ dll_unadorned))
+         else do str <- peekCString maybe_errmsg
+                 throwDyn (CmdLineError ("can't load .so/.DLL for: " 
+                                       ++ dll_unadorned ++ " (" ++ str ++ ")" ))
 
-locateOneObj :: [FilePath] -> String -> IO (Either FilePath String)
+locateOneObj :: [FilePath] -> String -> IO LibrarySpec
 locateOneObj []     obj 
    = return (Right obj) -- we assume
 locateOneObj (d:ds) obj 
@@ -780,6 +1147,20 @@ printTimes allocs psecs
 			 int allocs <+> text "bytes")))
 
 -----------------------------------------------------------------------------
+-- utils
+
+looksLikeModuleName [] = False
+looksLikeModuleName (c:cs) = isUpper c && all isAlphaNumEx cs
+
+isAlphaNumEx c = isAlphaNum c || c == '_' || c == '.'
+
+maybePutStr dflags s | verbosity dflags > 0 = putStr s
+		     | otherwise	    = return ()
+
+maybePutStrLn dflags s | verbosity dflags > 0 = putStrLn s
+		       | otherwise	      = return ()
+
+-----------------------------------------------------------------------------
 -- reverting CAFs
 	
 foreign import revertCAFs :: IO ()	-- make it "safe", just in case