+{-# LANGUAGE CPP, ForeignFunctionInterface #-}
+
-----------------------------------------------------------------------------
-- |
-- Module : System.Environment
-----------------------------------------------------------------------------
module System.Environment
- (
- , getArgs -- :: IO [String]
- , getProgName -- :: IO String
- , getEnv -- :: String -> IO String
+ (
+ getArgs, -- :: IO [String]
+ getProgName, -- :: IO String
+ getEnv, -- :: String -> IO String
+#ifndef __NHC__
+ withArgs,
+ withProgName,
+#endif
+#ifdef __GLASGOW_HASKELL__
+ getEnvironment,
+#endif
) where
import Prelude
+#ifdef __GLASGOW_HASKELL__
+import Data.List
import Foreign
import Foreign.C
+import Control.Exception.Base ( bracket )
import Control.Monad
+-- import GHC.IO
+import GHC.IO.Exception
+#endif
-#ifdef __GLASGOW_HASKELL__
-import GHC.IOBase
+#ifdef __HUGS__
+import Hugs.System
+#endif
+
+#ifdef __NHC__
+import System
+ ( getArgs
+ , getProgName
+ , getEnv
+ )
#endif
-- ---------------------------------------------------------------------------
-- getArgs, getProgName, getEnv
--- Computation `getArgs' returns a list of the program's command
+-- | Computation 'getArgs' returns a list of the program's command
-- line arguments (not including the program name).
+#ifdef __GLASGOW_HASKELL__
getArgs :: IO [String]
-getArgs =
- alloca $ \ p_argc ->
+getArgs =
+ alloca $ \ p_argc ->
alloca $ \ p_argv -> do
getProgArgv p_argc p_argv
p <- fromIntegral `liftM` peek p_argc
argv <- peek p_argv
peekArray (p - 1) (advancePtr argv 1) >>= mapM peekCString
-
+
foreign import ccall unsafe "getProgArgv"
getProgArgv :: Ptr CInt -> Ptr (Ptr CString) -> IO ()
is probably really @FOO.EXE@, and that is what 'getProgName' will return.
-}
getProgName :: IO String
-getProgName =
+getProgName =
alloca $ \ p_argc ->
alloca $ \ p_argv -> do
getProgArgv p_argc p_argv
argv <- peek p_argv
unpackProgName argv
-
-unpackProgName :: Ptr (Ptr CChar) -> IO String -- argv[0]
-unpackProgName argv = do
+
+unpackProgName :: Ptr (Ptr CChar) -> IO String -- argv[0]
+unpackProgName argv = do
s <- peekElemOff argv 0 >>= peekCString
return (basename s)
where
basename f = go f f
where
go acc [] = acc
- go acc (x:xs)
+ go acc (x:xs)
| isPathSeparator x = go xs xs
| otherwise = go acc xs
isPathSeparator :: Char -> Bool
isPathSeparator '/' = True
-#ifdef mingw32_TARGET_OS
+#ifdef mingw32_HOST_OS
isPathSeparator '\\' = True
#endif
isPathSeparator _ = False
--- Computation `getEnv var' returns the value
--- of the environment variable {\em var}.
-
--- This computation may fail with
--- NoSuchThing: The environment variable does not exist.
+-- | Computation 'getEnv' @var@ returns the value
+-- of the environment variable @var@.
+--
+-- This computation may fail with:
+--
+-- * 'System.IO.Error.isDoesNotExistError' if the environment variable
+-- does not exist.
getEnv :: String -> IO String
getEnv name =
withCString name $ \s -> do
litstring <- c_getenv s
if litstring /= nullPtr
- then peekCString litstring
+ then peekCString litstring
else ioException (IOError Nothing NoSuchThing "getEnv"
- "no environment variable" (Just name))
+ "no environment variable" Nothing (Just name))
foreign import ccall unsafe "getenv"
c_getenv :: CString -> IO (Ptr CChar)
+
+{-|
+'withArgs' @args act@ - while executing action @act@, have 'getArgs'
+return @args@.
+-}
+withArgs :: [String] -> IO a -> IO a
+withArgs xs act = do
+ p <- System.Environment.getProgName
+ withArgv (p:xs) act
+
+{-|
+'withProgName' @name act@ - while executing action @act@,
+have 'getProgName' return @name@.
+-}
+withProgName :: String -> IO a -> IO a
+withProgName nm act = do
+ xs <- System.Environment.getArgs
+ withArgv (nm:xs) act
+
+-- Worker routine which marshals and replaces an argv vector for
+-- the duration of an action.
+
+withArgv :: [String] -> IO a -> IO a
+withArgv new_args act = do
+ pName <- System.Environment.getProgName
+ existing_args <- System.Environment.getArgs
+ bracket (setArgs new_args)
+ (\argv -> do _ <- setArgs (pName:existing_args)
+ freeArgv argv)
+ (const act)
+
+freeArgv :: Ptr CString -> IO ()
+freeArgv argv = do
+ size <- lengthArray0 nullPtr argv
+ sequence_ [peek (argv `advancePtr` i) >>= free | i <- [size, size-1 .. 0]]
+ free argv
+
+setArgs :: [String] -> IO (Ptr CString)
+setArgs argv = do
+ vs <- mapM newCString argv >>= newArray0 nullPtr
+ setArgsPrim (genericLength argv) vs
+ return vs
+
+foreign import ccall unsafe "setProgArgv"
+ setArgsPrim :: CInt -> Ptr CString -> IO ()
+
+-- |'getEnvironment' retrieves the entire environment as a
+-- list of @(key,value)@ pairs.
+--
+-- If an environment entry does not contain an @\'=\'@ character,
+-- the @key@ is the whole entry and the @value@ is the empty string.
+
+getEnvironment :: IO [(String, String)]
+getEnvironment = do
+ pBlock <- getEnvBlock
+ if pBlock == nullPtr then return []
+ else do
+ stuff <- peekArray0 nullPtr pBlock >>= mapM peekCString
+ return (map divvy stuff)
+ where
+ divvy str =
+ case break (=='=') str of
+ (xs,[]) -> (xs,[]) -- don't barf (like Posix.getEnvironment)
+ (name,_:value) -> (name,value)
+
+foreign import ccall unsafe "__hscore_environ"
+ getEnvBlock :: IO (Ptr CString)
+#endif /* __GLASGOW_HASKELL__ */
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