REF make spawnPipe clearer

lib/XMonad/Internal/Shell.hs

@@ -101,10 +101,7 @@ spawnPipeRW
   -> m Handle
 spawnPipeRW x = do
   (r, h) <- liftIO mkPipe
-  void $ withRunInIO $ \runIO -> do
-    X.xfork $ runIO $ do
-      void $ liftIO $ dupTo r stdInput
-      liftIO $ executeFile "/bin/sh" False ["-c", T.unpack x] Nothing
+  child r
   liftIO $ closeFd r
   return h
   where
@@ -116,6 +113,10 @@ spawnPipeRW x = do
       hSetEncoding h utf8
       hSetBuffering h LineBuffering
       return (r, h)
+    child r = void $ withRunInIO $ \runIO -> do
+      X.xfork $ runIO $ do
+        void $ liftIO $ dupTo r stdInput
+        liftIO $ executeFile "/bin/sh" False ["-c", T.unpack x] Nothing
 
 -- | Run 'XMonad.Core.spawn' with a command and arguments
 spawnCmd :: MonadIO m => FilePath -> [T.Text] -> m ()