[project @ 2005-01-28 15:03:06 by simonmar]

[ghc-base.git] / System / Environment.hs

diff --git a/System/Environment.hs b/System/Environment.hs
index 02c11a7..3271e29 100644 (file)
--- a/System/Environment.hs
+++ b/System/Environment.hs
@@ -17,20 +17,22 @@ module System.Environment
       getArgs,      -- :: IO [String]
       getProgName,   -- :: IO String
       getEnv,        -- :: String -> IO String
+#ifndef __NHC__
       withArgs,
       withProgName,
+#endif
+#ifdef __GLASGOW_HASKELL__
+      getEnvironment,
+#endif
   ) where
 
 import Prelude
-import System.IO       ( bracket )
 
-#ifndef __HUGS__
+#ifdef __GLASGOW_HASKELL__
 import Foreign
 import Foreign.C
+import Control.Exception       ( bracket )
 import Control.Monad
-#endif
-
-#ifdef __GLASGOW_HASKELL__
 import GHC.IOBase
 #endif
 
@@ -38,13 +40,21 @@ import GHC.IOBase
 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).
 
-#ifndef __HUGS__
+#ifdef __GLASGOW_HASKELL__
 getArgs :: IO [String]
 getArgs = 
   alloca $ \ p_argc ->  
@@ -91,17 +101,19 @@ unpackProgName argv = do
 
    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 =
@@ -114,19 +126,21 @@ getEnv name =
 
 foreign import ccall unsafe "getenv"
    c_getenv :: CString -> IO (Ptr CChar)
-#endif  /* __HUGS__ */
 
 {-|
-@withArgs args act@ - while executing action @act@, have 'System.getArgs'
+'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 'System.getProgName'return @name@.
+'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
@@ -134,6 +148,7 @@ withProgName nm act = do
 -- 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
@@ -155,3 +170,26 @@ setArgs argv = do
 
 foreign import ccall unsafe "setProgArgv" 
   setArgsPrim  :: Int -> 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__ */