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diff --git a/server/src/ControlMaybe.hs b/server/src/ControlMaybe.hs
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+{-# LANGUAGE CPP                 #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+module ControlMaybe
+   ( module ControlMaybe
+   , module Data.Functor
+   ) where
+
+-- import GHC.IO.Exception (IOException(..))
+import Control.Monad
+import Data.Functor
+import System.IO.Error
+
+
+-- forM_ with less polymorphism.
+withJust :: Monad m => Maybe x -> (x -> m ()) -> m ()
+withJust m f = forM_ m f
+{-# INLINE withJust #-}
+
+whenJust :: Monad m => m (Maybe x) -> (x -> m ()) -> m ()
+whenJust acn f = acn >>= mapM_ f
+{-# INLINE whenJust #-}
+
+
+catchIO_ :: IO a -> IO a -> IO a
+catchIO_ body catcher = catchIOError body (\_ -> catcher)
+{-# INLINE catchIO_ #-}
+
+handleIO_ :: IO a -> IO a -> IO a
+handleIO_ catcher body = catchIOError body (\_ -> catcher)
+{-# INLINE handleIO_ #-}
+
+
+handleIO :: (IOError -> IO a) -> IO a -> IO a
+handleIO catcher body = catchIOError body catcher
+{-# INLINE handleIO #-}
+
+#if !MIN_VERSION_base(4,11,0)
+-- | Flipped version of '<$>'.
+--
+-- @
+-- ('<&>') = 'flip' 'fmap'
+-- @
+--
+-- @since 4.11.0.0
+--
+-- ==== __Examples__
+-- Apply @(+1)@ to a list, a 'Data.Maybe.Just' and a 'Data.Either.Right':
+--
+-- >>> Just 2 <&> (+1)
+-- Just 3
+--
+-- >>> [1,2,3] <&> (+1)
+-- [2,3,4]
+--
+-- >>> Right 3 <&> (+1)
+-- Right 4
+--
+(<&>) :: Functor f => f a -> (a -> b) -> f b
+as <&> f = f <$> as
+
+infixl 1 <&>
+#endif
+
+