module System.Environment
(
- getArgs -- :: IO [String]
- , getProgName -- :: IO String
- , getEnv -- :: String -> IO String
+ getArgs, -- :: IO [String]
+ getProgName, -- :: IO String
+ getEnv, -- :: String -> IO String
+#ifdef __GLASGOW_HASKELL__
+ withArgs,
+ withProgName,
+#endif
) where
import Prelude
+import Control.Exception ( bracket )
-#ifndef __HUGS__
+#ifdef __GLASGOW_HASKELL__
import Foreign
import Foreign.C
import Control.Monad
-#endif
-
-#ifdef __GLASGOW_HASKELL__
import GHC.IOBase
#endif
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
-- line arguments (not including the program name).
-#ifndef __HUGS__
+#ifdef __GLASGOW_HASKELL__
getArgs :: IO [String]
getArgs =
alloca $ \ p_argc ->
foreign import ccall unsafe "getenv"
c_getenv :: CString -> IO (Ptr CChar)
-#endif /* __HUGS__ */
+
+{-|
+@withArgs args act@ - while executing action @act@, have 'System.getArgs'
+return @args@.
+-}
+withArgs xs act = do
+ p <- System.Environment.getProgName
+ withArgv (p:xs) act
+
+{-|
+@withProgName name act@ - while executing action @act@, have 'System.getProgName'return @name@.
+-}
+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 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 (length argv) vs
+ return vs
+
+foreign import ccall unsafe "setProgArgv"
+ setArgsPrim :: Int -> Ptr CString -> IO ()
+#endif /* __GLASGOW_HASKELL__ */