+% -----------------------------------------------------------------------------
+% $Id: System.lhs,v 1.29 2001/01/11 17:51:02 simonmar Exp $
%
-% (c) The AQUA Project, Glasgow University, 1994-1999
+% (c) The University of Glasgow, 1994-2000
%
\section[System]{Module @System@}
) where
\end{code}
-
-#ifndef __HUGS__
\begin{code}
+import Monad
import Prelude
-import PrelAddr
-import PrelIOBase ( IOError(..), IOErrorType(..), constructErrorAndFailWithInfo, stToIO )
-import PrelPack ( unpackCString, unpackCStringST, packString )
-import PrelArr ( ByteArray )
-
-type PrimByteArray = ByteArray Int
-
-primUnpackCString :: Addr -> IO String
-primUnpackCString s = stToIO ( unpackCStringST s )
-
-primPackString :: String -> PrimByteArray
-primPackString s = packString s
-
+import PrelCString
+import PrelCTypes
+import PrelMarshalArray
+import PrelPtr
+import PrelStorable
+import PrelIOBase ( IOException(..), ioException,
+ IOErrorType(..), constructErrorAndFailWithInfo )
\end{code}
%*********************************************************
line arguments (not including the program name).
\begin{code}
-getArgs :: IO [String]
-getArgs = return (unpackArgv primArgv primArgc)
+getArgs :: IO [String]
+getArgs = unpackArgv primArgv primArgc
-foreign import ccall "libHS_cbits.so" "get_prog_argv" unsafe primArgv :: Addr
-foreign import ccall "libHS_cbits.so" "get_prog_argc" unsafe primArgc :: Int
+foreign import ccall "get_prog_argv" unsafe primArgv :: Ptr (Ptr CChar)
+foreign import ccall "get_prog_argc" unsafe primArgc :: Int
\end{code}
Computation $getProgName$ returns the name of the program
as it was invoked.
\begin{code}
-getProgName :: IO String
-getProgName = return (unpackProgName primArgv)
+getProgName :: IO String
+getProgName = unpackProgName primArgv
\end{code}
Computation $getEnv var$ returns the value
\end{itemize}
\begin{code}
-getEnv :: String -> IO String
-getEnv name = do
- litstring <- primGetEnv (primPackString name)
- if litstring /= nullAddr
- then primUnpackCString litstring
- else ioError (IOError Nothing NoSuchThing "getEnv"
- ("environment variable: " ++ name))
-
-foreign import ccall "libHS_cbits.so" "getenv" unsafe primGetEnv :: PrimByteArray -> IO Addr
+getEnv :: String -> IO String
+getEnv name =
+ withUnsafeCString name $ \s -> do
+ litstring <- _getenv s
+ if litstring /= nullPtr
+ then peekCString litstring
+ else ioException (IOError Nothing NoSuchThing "getEnv"
+ "no environment variable" (Just name))
+
+foreign import ccall "getenv" unsafe _getenv :: UnsafeCString -> IO (Ptr CChar)
\end{code}
Computation $system cmd$ returns the exit code
\begin{code}
system :: String -> IO ExitCode
-system "" = ioError (IOError Nothing InvalidArgument "system" "null command")
-system cmd = do
- status <- primSystem (primPackString cmd)
+system "" = ioException (IOError Nothing InvalidArgument "system" "null command" Nothing)
+system cmd =
+ withUnsafeCString cmd $ \s -> do
+ status <- primSystem s
case status of
0 -> return ExitSuccess
-1 -> constructErrorAndFailWithInfo "system" cmd
n -> return (ExitFailure n)
-foreign import ccall "libHS_cbits.so" "systemCmd" unsafe primSystem :: PrimByteArray -> IO Int
+foreign import ccall "systemCmd" unsafe primSystem :: UnsafeCString -> IO Int
\end{code}
@exitWith code@ terminates the program, returning {\em code} to the program's caller.
exitWith :: ExitCode -> IO a
exitWith ExitSuccess = do
primExit 0
- ioError (IOError Nothing OtherError "exitWith" "exit should not return")
+ ioException (IOError Nothing OtherError "exitWith" "exit should not return" Nothing)
exitWith (ExitFailure n)
- | n == 0 = ioError (IOError Nothing InvalidArgument "exitWith" "ExitFailure 0")
+ | n == 0 = ioException (IOError Nothing InvalidArgument "exitWith" "ExitFailure 0" Nothing)
| otherwise = do
primExit n
- ioError (IOError Nothing OtherError "exitWith" "exit should not return")
+ ioException (IOError Nothing OtherError "exitWith" "exit should not return" Nothing)
+-- NOTE: shutdownHaskellAndExit must be called "safe", because it *can*
+-- re-enter Haskell land through finalizers.
foreign import ccall "shutdownHaskellAndExit" primExit :: Int -> IO ()
exitFailure :: IO a
%*********************************************************
\begin{code}
-type CHAR_STAR_STAR = Addr -- this is all a HACK
-type CHAR_STAR = Addr
-
-unpackArgv :: CHAR_STAR_STAR -> Int -> [String] -- argv[1 .. argc-1]
-unpackArgv argv argc = unpack 1
- where
- unpack :: Int -> [String]
- unpack n
- | n >= argc = []
- | otherwise =
- case (indexAddrOffAddr argv n) of
- item -> unpackCString item : unpack (n + 1)
-
-unpackProgName :: CHAR_STAR_STAR -> String -- argv[0]
-unpackProgName argv
- = case (indexAddrOffAddr argv 0) of { prog ->
- de_slash [] (unpackCString prog) }
+unpackArgv :: Ptr (Ptr CChar) -> Int -> IO [String] -- argv[1 .. argc-1]
+unpackArgv argv argc
+ = peekArray (argc-1) (advancePtr argv 1) >>= mapM peekCString
+
+unpackProgName :: Ptr (Ptr CChar) -> IO String -- argv[0]
+unpackProgName argv = do
+ s <- peekElemOff argv 0 >>= peekCString
+ return (de_slash "" s)
where
-- re-start accumulating at every '/'
de_slash :: String -> String -> String
de_slash _acc ('/':xs) = de_slash [] xs
de_slash acc (x:xs) = de_slash (x:acc) xs
\end{code}
-
-#else
-
-\begin{code}
------------------------------------------------------------------------------
--- Standard Library: System operations
---
--- Warning: the implementation of these functions in Hugs 98 is very weak.
--- The functions themselves are best suited to uses in compiled programs,
--- and not to use in an interpreter-based environment like Hugs.
---
--- Suitable for use with Hugs 98
------------------------------------------------------------------------------
-
-data ExitCode = ExitSuccess | ExitFailure Int
- deriving (Eq, Ord, Read, Show)
-
-getArgs :: IO [String]
-getArgs = primGetRawArgs >>= \rawargs ->
- return (drop 1 (dropWhile (/= "--") rawargs))
-
-getProgName :: IO String
-getProgName = primGetRawArgs >>= \rawargs ->
- return (head rawargs)
-
-getEnv :: String -> IO String
-getEnv = primGetEnv
-
-system :: String -> IO ExitCode
-system s = error "System.system unimplemented"
-
-exitWith :: ExitCode -> IO a
-exitWith c = error "System.exitWith unimplemented"
-
-exitFailure :: IO a
-exitFailure = exitWith (ExitFailure 1)
-
-toExitCode :: Int -> ExitCode
-toExitCode 0 = ExitSuccess
-toExitCode n = ExitFailure n
-
-fromExitCode :: ExitCode -> Int
-fromExitCode ExitSuccess = 0
-fromExitCode (ExitFailure n) = n
-
------------------------------------------------------------------------------
-\end{code}
-#endif
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