[project @ 2000-11-16 10:48:22 by simonmar]

on second thoughts, add this somewhere more sensible

ghc/compiler/ghci/InteractiveUI.hs

+-----------------------------------------------------------------------------
+-- $Id: InteractiveUI.hs,v 1.1 2000/11/16 10:48:22 simonmar Exp $
+--
+-- GHC Interactive User Interface
+--
+-- (c) The GHC Team 2000
+--
+-----------------------------------------------------------------------------
+
+module InteractiveUI where
+
+import CompManager
+import Module
+import Panic
+import Util
+
+import Readline
+
+import System
+import Directory
+import IO
+import Char
+
+-----------------------------------------------------------------------------
+
+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),
+  ("quit",	quit),
+  ("!",		shellEscape)
+  ]
+
+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\ 
+\"
+
+interactiveUI :: CmState -> IO ()
+interactiveUI st = do
+   hPutStr stdout ghciWelcomeMsg
+   hFlush stdout
+   hSetBuffering stdout NoBuffering
+#ifndef NO_READLINE
+   Readline.initialize
+#endif
+   _ <- (unGHCi uiLoop) GHCiState{ current_module = mkModuleName "Prelude", 
+	  	                   target = Nothing,
+			           cmstate = st }
+   return ()
+
+uiLoop :: GHCi ()
+uiLoop = do
+  st <- getGHCiState
+#ifndef NO_READLINE
+  l <- io (readline (moduleNameUserString (current_module st)  ++ ">"))
+#else
+  l <- io (hGetLine stdin)
+#endif
+  case l of
+    Nothing -> return ()
+    Just "" -> uiLoop
+    Just l  -> do
+#ifndef NO_READLINE
+          io (addHistory l)
+#endif
+  	  runCommand l
+	  uiLoop  
+
+runCommand c = myCatch (doCommand c) 
+			(\e -> io (hPutStr stdout ("Error: " ++ show e)))
+
+doCommand (':' : command) = specialCommand command
+doCommand expr = do
+  io (hPutStrLn stdout ("Run expression: " ++ expr))
+  return ()
+
+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)
+     [(_,f)] -> f rest
+     cs      -> io $ hPutStrLn stdout ("prefix " ++ cmd ++ 
+			    	       " matches multiple commands (" ++ 
+	         	     	       foldr1 (\a b -> a ++ ',':b) (map fst cs) ++ ")")
+
+noArgs c = io (hPutStr stdout ("command `:" ++ c ++ "' takes no arguments"))
+
+-----------------------------------------------------------------------------
+-- Commands
+
+-- ToDo: don't forget to catch errors
+
+help :: String -> GHCi ()
+help _ = io (putStr helpText)
+
+changeDirectory :: String -> GHCi ()
+changeDirectory = io . setCurrentDirectory
+
+loadModule :: String -> GHCi ()
+loadModule path = do
+  state <- getGHCiState
+  (new_cmstate, mod) <- io (cmLoadModule (cmstate state) ({-ToDo!!-}mkModuleName path))
+  setGHCiState state{cmstate=new_cmstate, target=Just path}  
+
+reloadModule :: String -> GHCi ()
+reloadModule "" = do
+  state <- getGHCiState
+  case target state of
+	Nothing -> io (hPutStr stdout "no current target")
+	Just path -> do (new_cmstate, mod) <- io (cmLoadModule (cmstate state) (mkModuleName path))
+  			setGHCiState state{cmstate=new_cmstate}  
+reloadModule _ = noArgs ":reload"
+
+setOptions :: String -> GHCi ()
+setOptions = panic "setOptions"
+
+typeOfExpr :: String -> GHCi ()
+typeOfExpr = panic "typeOfExpr"
+
+quit :: String -> GHCi ()
+quit _ = return ()
+
+shellEscape :: String -> GHCi ()
+shellEscape str = io (system str >> return ())
+
+-----------------------------------------------------------------------------
+-- GHCi monad
+
+data GHCiState = GHCiState
+     { 
+	current_module :: ModuleName,
+	target         :: Maybe FilePath,
+	cmstate        :: CmState
+     }
+
+newtype GHCi a = GHCi { unGHCi :: GHCiState -> IO (GHCiState, a) }
+
+instance Monad GHCi where
+  (GHCi m) >>= k  =  GHCi $ \s -> m s >>= \(s,a) -> unGHCi (k a) s
+  return a  = GHCi $ \s -> return (s,a)
+
+getGHCiState   = GHCi $ \s -> return (s,s)
+setGHCiState s = GHCi $ \_ -> return (s,())
+
+io m = GHCi $ \s -> m >>= \a -> return (s,a)
+
+myCatch (GHCi m) h = GHCi $ \s -> catch (m s) (\e -> unGHCi (h e) s)