+% -----------------------------------------------------------------------------
+% $Id: System.lhs,v 1.26 2000/07/07 11:03:58 simonmar Exp $
%
-% (c) The AQUA Project, Glasgow University, 1994-1999
+% (c) The University of Glasgow, 1994-2000
%
\section[System]{Module @System@}
, exitWith -- :: ExitCode -> IO a
, exitFailure -- :: IO a
) where
+\end{code}
-#ifdef __HUGS__
-import PreludeBuiltin
-
-indexAddrOffAddr = primIndexAddrOffAddr
-
-unpackCString = unsafeUnpackCString
-#else
+#ifndef __HUGS__
+\begin{code}
import Prelude
import PrelAddr
-import PrelIOBase ( IOError(..), IOErrorType(..), constructErrorAndFailWithInfo, stToIO )
+import PrelIOBase ( IOException(..), ioException,
+ IOErrorType(..), constructErrorAndFailWithInfo, stToIO )
import PrelPack ( unpackCString, unpackCStringST, packString )
-import PrelArr ( ByteArray )
+import PrelByteArr ( ByteArray )
type PrimByteArray = ByteArray Int
primPackString :: String -> PrimByteArray
primPackString s = packString s
-#endif
\end{code}
litstring <- primGetEnv (primPackString name)
if litstring /= nullAddr
then primUnpackCString litstring
- else ioError (IOError Nothing NoSuchThing "getEnv"
- ("environment variable: " ++ name))
+ else ioException (IOError Nothing NoSuchThing "getEnv"
+ ("environment variable: " ++ name))
foreign import ccall "libHS_cbits.so" "getenv" unsafe primGetEnv :: PrimByteArray -> IO Addr
\end{code}
\begin{code}
system :: String -> IO ExitCode
-system "" = ioError (IOError Nothing InvalidArgument "system" "null command")
+system "" = ioException (IOError Nothing InvalidArgument "system" "null command")
system cmd = do
status <- primSystem (primPackString cmd)
case status of
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")
exitWith (ExitFailure n)
- | n == 0 = ioError (IOError Nothing InvalidArgument "exitWith" "ExitFailure 0")
+ | n == 0 = ioException (IOError Nothing InvalidArgument "exitWith" "ExitFailure 0")
| otherwise = do
primExit n
- ioError (IOError Nothing OtherError "exitWith" "exit should not return")
+ ioException (IOError Nothing OtherError "exitWith" "exit should not return")
+-- 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
type CHAR_STAR_STAR = Addr -- this is all a HACK
type CHAR_STAR = Addr
-unpackArgv :: CHAR_STAR_STAR -> Int -> [String] -- argv[1 .. argc-1]
-unpackProgName :: CHAR_STAR_STAR -> String -- argv[0]
-
+unpackArgv :: CHAR_STAR_STAR -> Int -> [String] -- argv[1 .. argc-1]
unpackArgv argv argc = unpack 1
where
- unpack :: Int -> [String]
- unpack n
- = if (n >= argc)
- then ([] :: [String])
- else case (indexAddrOffAddr argv n) of { item ->
- unpackCString item : unpack (n + 1) }
+ 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) }
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
+-----------------------------------------------------------------------------
+import PrelPrim ( primGetRawArgs
+ , primGetEnv
+ , prelCleanupAfterRunAction
+ , copy_String_to_cstring
+ , readIORef
+ , nh_stderr
+ , nh_stdout
+ , nh_stdin
+ , nh_exitwith
+ , nh_flush
+ , nh_close
+ , nh_system
+ , nh_free
+ , nh_getPID
+ )
+
+
+data ExitCode = ExitSuccess | ExitFailure Int
+ deriving (Eq, Ord, Read, Show)
+
+getArgs :: IO [String]
+getArgs = primGetRawArgs >>= \rawargs ->
+ return (tail rawargs)
+
+getProgName :: IO String
+getProgName = primGetRawArgs >>= \rawargs ->
+ return (head rawargs)
+
+getEnv :: String -> IO String
+getEnv = primGetEnv
+
+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
+
+-- see comment in Prelude.hs near primRunIO_hugs_toplevel
+exitWith :: ExitCode -> IO a
+exitWith c
+ = do cleanup_action <- readIORef prelCleanupAfterRunAction
+ case cleanup_action of
+ Just xx -> xx
+ Nothing -> return ()
+ nh_stderr >>= nh_flush
+ nh_stdout >>= nh_flush
+ nh_stdin >>= nh_close
+ nh_exitwith (fromExitCode c)
+ (ioException . IOError) "System.exitWith: should not return"
+
+system :: String -> IO ExitCode
+system cmd
+ | null cmd
+ = (ioException.IOError) "System.system: null command"
+ | otherwise
+ = do str <- copy_String_to_cstring cmd
+ status <- nh_system str
+ nh_free str
+ case status of
+ 0 -> return ExitSuccess
+ n -> return (ExitFailure n)
+
+getPID :: IO Int
+getPID
+ = nh_getPID
+
+-----------------------------------------------------------------------------
+\end{code}
+#endif
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