1 files changed, 15 insertions, 6 deletions
diff --git a/System/Posix/Env/ByteString.hsc b/System/Posix/Env/ByteString.hsc
index c6c374c..3ce867b 100644
--- a/System/Posix/Env/ByteString.hsc
+++ b/System/Posix/Env/ByteString.hsc
@@ -45,7 +45,9 @@ import Data.ByteString (ByteString)
 
 -- |'getEnv' looks up a variable in the environment.
 
-getEnv :: ByteString -> IO (Maybe ByteString)
+getEnv ::
+  ByteString            {- ^ variable name  -} ->
+  IO (Maybe ByteString) {- ^ variable value -}
 getEnv name = do
   litstring <- B.useAsCString name c_getenv
   if litstring /= nullPtr
@@ -56,7 +58,10 @@ getEnv name = do
 -- programmer can specify a fallback if the variable is not found
 -- in the environment.
 
-getEnvDefault :: ByteString -> ByteString -> IO ByteString
+getEnvDefault ::
+  ByteString    {- ^ variable name                    -} ->
+  ByteString    {- ^ fallback value                   -} ->
+  IO ByteString {- ^ variable value or fallback value -}
 getEnvDefault name fallback = liftM (fromMaybe fallback) (getEnv name)
 
 foreign import ccall unsafe "getenv"
@@ -86,7 +91,7 @@ foreign import ccall unsafe "&environ"
 -- |'getEnvironment' retrieves the entire environment as a
 -- list of @(key,value)@ pairs.
 
-getEnvironment :: IO [(ByteString,ByteString)]
+getEnvironment :: IO [(ByteString,ByteString)] {- ^ @[(key,value)]@ -}
 getEnvironment = do
   env <- getEnvironmentPrim
   return $ map (dropEq.(BC.break ((==) '='))) env
@@ -98,7 +103,7 @@ getEnvironment = do
 -- |The 'unsetEnv' function deletes all instances of the variable name
 -- from the environment.
 
-unsetEnv :: ByteString -> IO ()
+unsetEnv :: ByteString {- ^ variable name -} -> IO ()
 #if HAVE_UNSETENV
 # if !UNSETENV_RETURNS_VOID
 unsetEnv name = B.useAsCString name $ \ s ->
@@ -121,7 +126,7 @@ unsetEnv name = putEnv (name ++ "=")
 -- |'putEnv' function takes an argument of the form @name=value@
 -- and is equivalent to @setEnv(key,value,True{-overwrite-})@.
 
-putEnv :: ByteString -> IO ()
+putEnv :: ByteString {- ^ "key=value" -} -> IO ()
 putEnv keyvalue = B.useAsCString keyvalue $ \s ->
   throwErrnoIfMinus1_ "putenv" (c_putenv s)
 
@@ -135,7 +140,11 @@ foreign import ccall unsafe "putenv"
      not reset, otherwise it is reset to the given value.
 -}
 
-setEnv :: ByteString -> ByteString -> Bool {-overwrite-} -> IO ()
+setEnv ::
+  ByteString {- ^ variable name  -} ->
+  ByteString {- ^ variable value -} ->
+  Bool       {- ^ overwrite      -} ->
+  IO ()
 #ifdef HAVE_SETENV
 setEnv key value ovrwrt = do
   B.useAsCString key $ \ keyP ->