Apply hlint hints

All hints are applied in one single commit, as a commit per hint would
result in 80+ separate commits—tihs is really just too much noise.

Related: https://github.com/xmonad/xmonad-contrib/issues/537

XMonad/Actions/BluetileCommands.hs

@@ -42,7 +42,7 @@ import System.Exit
 
 workspaceCommands :: Int -> X [(String, X ())]
 workspaceCommands sid = asks (workspaces . config) >>= \spaces -> return
-                            [(("greedyView" ++ show i),
+                            [( "greedyView" ++ show i,
                                 activateScreen sid >> windows (W.greedyView i))
                                 | i <- spaces ]
 
@@ -65,7 +65,7 @@ masterAreaCommands sid = [ ("increase master n", activateScreen sid >>
                          ]
 
 quitCommands :: [(String, X ())]
-quitCommands = [ ("quit bluetile", io (exitWith ExitSuccess))
+quitCommands = [ ("quit bluetile", io exitSuccess)
                , ("quit bluetile and start metacity", restart "metacity" False)
                ]
 

XMonad/Actions/Commands.hs

@@ -61,18 +61,18 @@ import XMonad.Prelude
 -- | Create a 'Data.Map.Map' from @String@s to xmonad actions from a
 --   list of pairs.
 commandMap :: [(String, X ())] -> M.Map String (X ())
-commandMap c = M.fromList c
+commandMap = M.fromList
 
 -- | Generate a list of commands to switch to\/send windows to workspaces.
 workspaceCommands :: X [(String, X ())]
 workspaceCommands = asks (workspaces . config) >>= \spaces -> return
-                            [((m ++ show i), windows $ f i)
+                            [( m ++ show i, windows $ f i)
                                 | i <- spaces
                                 , (f, m) <- [(view, "view"), (shift, "shift")] ]
 
 -- | Generate a list of commands dealing with multiple screens.
 screenCommands :: [(String, X ())]
-screenCommands = [((m ++ show sc), screenWorkspace (fromIntegral sc) >>= flip whenJust (windows . f))
+screenCommands = [( m ++ show sc, screenWorkspace (fromIntegral sc) >>= flip whenJust (windows . f))
                       | sc <- [0, 1]::[Int] -- TODO: adapt to screen changes
                       , (f, m) <- [(view, "screen"), (shift, "screen-to-")]
                  ]
@@ -100,7 +100,7 @@ defaultCommands = do
         , ("swap-down"           , windows swapDown                                 )
         , ("swap-master"         , windows swapMaster                               )
         , ("sink"                , withFocused $ windows . sink                     )
-        , ("quit-wm"             , io $ exitWith ExitSuccess                        )
+        , ("quit-wm"             , io exitSuccess                                   )
         ]
 
 -- | Given a list of command\/action pairs, prompt the user to choose a

XMonad/Actions/CopyWindow.hs

@@ -96,7 +96,7 @@ copy n s | Just w <- W.peek s = copyWindow w n s
 
 -- | Copy the focused window to all workspaces.
 copyToAll :: (Eq s, Eq i, Eq a) => W.StackSet i l a s sd -> W.StackSet i l a s sd
-copyToAll s = foldr copy s $ map W.tag (W.workspaces s)
+copyToAll s = foldr (copy . W.tag) s (W.workspaces s)
 
 -- | Copy an arbitrary window to a workspace.
 copyWindow :: (Eq a, Eq i, Eq s) => a -> i -> W.StackSet i l a s sd -> W.StackSet i l a s sd
@@ -142,9 +142,9 @@ killAllOtherCopies = do ss <- gets windowset
                                                    W.view (W.currentTag ss) .
                                                    delFromAllButCurrent w
     where
-      delFromAllButCurrent w ss = foldr ($) ss $
-                                  map (delWinFromWorkspace w . W.tag) $
-                                  W.hidden ss ++ map W.workspace (W.visible ss)
+      delFromAllButCurrent w ss = foldr (delWinFromWorkspace w . W.tag)
+                                  ss
+                                  (W.hidden ss ++ map W.workspace (W.visible ss))
       delWinFromWorkspace w wid = viewing wid $ W.modify Nothing (W.filter (/= w))
 
       viewing wis f ss = W.view (W.currentTag ss) $ f $ W.view wis ss

XMonad/Actions/CycleSelectedLayouts.hs

@@ -18,7 +18,7 @@ module XMonad.Actions.CycleSelectedLayouts (
     cycleThroughLayouts) where
 
 import XMonad
-import XMonad.Prelude (findIndex, fromMaybe)
+import XMonad.Prelude (elemIndex, fromMaybe)
 import qualified XMonad.StackSet as S
 
 -- $usage
@@ -32,7 +32,7 @@ import qualified XMonad.StackSet as S
 cycleToNext :: (Eq a) => [a] -> a -> Maybe a
 cycleToNext lst a = do
     -- not beautiful but simple and readable
-    ind <- findIndex (a==) lst
+    ind <- elemIndex a lst
     return $ lst !! if ind == length lst - 1 then 0 else ind+1
 
 -- | If the current layout is in the list, cycle to the next layout. Otherwise,

XMonad/Actions/CycleWS.hs

@@ -199,8 +199,7 @@ skipTags wss ids = filter ((`notElem` ids) . tag) wss
 lastViewedHiddenExcept :: [WorkspaceId] -> X (Maybe WorkspaceId)
 lastViewedHiddenExcept skips = do
     hs <- gets $ map tag . flip skipTags skips . hidden . windowset
-    vs <- WH.workspaceHistory
-    return $ choose hs (find (`elem` hs) vs)
+    choose hs . find (`elem` hs) <$> WH.workspaceHistory
     where choose []    _           = Nothing
           choose (h:_) Nothing     = Just h
           choose _     vh@(Just _) = vh
@@ -211,7 +210,7 @@ switchWorkspace d = wsBy d >>= windows . greedyView
 shiftBy :: Int -> X ()
 shiftBy d = wsBy d >>= windows . shift
 
-wsBy :: Int -> X (WorkspaceId)
+wsBy :: Int -> X WorkspaceId
 wsBy = findWorkspace getSortByIndex Next AnyWS
 
 {- $taketwo
@@ -260,7 +259,7 @@ wsTypeToPred HiddenEmptyWS  = do ne <- wsTypeToPred EmptyWS
                                  hi <- wsTypeToPred HiddenWS
                                  return (\w -> hi w && ne w)
 wsTypeToPred AnyWS      = return (const True)
-wsTypeToPred (WSTagGroup sep) = do cur <- (groupName.workspace.current) <$> gets windowset
+wsTypeToPred (WSTagGroup sep) = do cur <- groupName.workspace.current <$> gets windowset
                                    return $ (cur ==).groupName
                                    where groupName = takeWhile (/=sep).tag
 wsTypeToPred (WSIs p)   = p
@@ -297,7 +296,7 @@ findWorkspace :: X WorkspaceSort -> Direction1D -> WSType -> Int -> X WorkspaceI
 findWorkspace s dir t n = findWorkspaceGen s (wsTypeToPred t) (maybeNegate dir n)
   where
     maybeNegate Next d = d
-    maybeNegate Prev d = (-d)
+    maybeNegate Prev d = -d
 
 findWorkspaceGen :: X WorkspaceSort -> X (WindowSpace -> Bool) -> Int -> X WorkspaceId
 findWorkspaceGen _ _ 0 = gets (currentTag . windowset)
@@ -307,7 +306,7 @@ findWorkspaceGen sortX wsPredX d = do
     ws     <- gets windowset
     let cur     = workspace (current ws)
         sorted  = sort (workspaces ws)
-        pivoted = let (a,b) = span ((/= (tag cur)) . tag) sorted in b ++ a
+        pivoted = let (a,b) = span ((/= tag cur) . tag) sorted in b ++ a
         ws'     = filter wsPred pivoted
         mCurIx  = findWsIndex cur ws'
         d'      = if d > 0 then d - 1 else d
@@ -319,7 +318,7 @@ findWorkspaceGen sortX wsPredX d = do
     return $ tag next
 
 findWsIndex :: WindowSpace -> [WindowSpace] -> Maybe Int
-findWsIndex ws wss = findIndex ((== tag ws) . tag) wss
+findWsIndex ws = findIndex ((== tag ws) . tag)
 
 -- | View next screen
 nextScreen :: X ()
@@ -347,7 +346,7 @@ the default screen keybindings:
 >         , (f, m) <- [(W.view, 0), (W.shift, shiftMask)]]
 
 -}
-screenBy :: Int -> X (ScreenId)
+screenBy :: Int -> X ScreenId
 screenBy d = do ws <- gets windowset
                 --let ss = sortBy screen (screens ws)
                 let now = screen (current ws)

XMonad/Actions/CycleWindows.hs

@@ -116,7 +116,7 @@ cycleRecentWindows :: [KeySym] -- ^ A list of modifier keys used when invoking t
                                --   If it's the same as the first key, it is effectively ignored.
                     -> X ()
 cycleRecentWindows = cycleStacks' stacks where
-    stacks s = map (shiftToFocus' `flip` s) (wins s)
+    stacks s = map (`shiftToFocus'` s) (wins s)
     wins (W.Stack t l r) = t : r ++ reverse l
 
 
@@ -205,7 +205,7 @@ rotFocused' :: ([a] -> [a]) -> W.Stack a -> W.Stack a
 rotFocused' _ s@(W.Stack _ [] []) = s
 rotFocused' f   (W.Stack t [] (r:rs)) = W.Stack t' [] (r:rs') -- Master has focus
     where (t':rs') = f (t:rs)
-rotFocused' f s@(W.Stack _ _ _) = rotSlaves' f s              -- otherwise
+rotFocused' f s@W.Stack{} = rotSlaves' f s                    -- otherwise
 
 
 -- $unfocused

XMonad/Actions/CycleWorkspaceByScreen.hs

@@ -49,7 +49,7 @@ repeatableAction mods pressHandler = do
                    return (t, s)
       handleEvent (t, s)
         | t == keyRelease && s `elem` mods = return ()
-        | otherwise = (pressHandler t s) >> getNextEvent >>= handleEvent
+        | otherwise = pressHandler t s >> getNextEvent >>= handleEvent
 
   io $ grabKeyboard d root False grabModeAsync grabModeAsync currentTime
   getNextEvent >>= handleEvent
@@ -81,9 +81,9 @@ cycleWorkspaceOnScreen screenId mods nextKey prevKey = workspaceHistoryTransacti
         current <- readIORef currentWSIndex
         modifyIORef
           currentWSIndex
-          ((`mod` (length cycleWorkspaces)) . (+ increment))
+          ((`mod` length cycleWorkspaces) . (+ increment))
         return $ cycleWorkspaces !! current
-      focusIncrement i = (io $ getAndIncrementWS i) >>= (windows . W.greedyView)
+      focusIncrement i = io (getAndIncrementWS i) >>= (windows . W.greedyView)
 
   focusIncrement 1 -- Do the first workspace cycle
   repeatableAction mods $

XMonad/Actions/DynamicWorkspaceGroups.hs

@@ -44,7 +44,7 @@ import Control.Arrow ((&&&))
 import qualified Data.Map as M
 
 import XMonad
-import XMonad.Prelude (find)
+import XMonad.Prelude (find, for_)
 import qualified XMonad.StackSet as W
 
 import XMonad.Prompt
@@ -68,14 +68,14 @@ type WSGroup = [(ScreenId,WorkspaceId)]
 
 type WSGroupId = String
 
-data WSGroupStorage = WSG { unWSG :: M.Map WSGroupId WSGroup }
+newtype WSGroupStorage = WSG { unWSG :: M.Map WSGroupId WSGroup }
   deriving (Typeable, Read, Show)
 
 withWSG :: (M.Map WSGroupId WSGroup -> M.Map WSGroupId WSGroup) -> WSGroupStorage -> WSGroupStorage
 withWSG f = WSG . f . unWSG
 
 instance ExtensionClass WSGroupStorage where
-  initialValue = WSG $ M.empty
+  initialValue = WSG M.empty
   extensionType = PersistentExtension
 
 -- | Add a new workspace group of the given name, mapping to an
@@ -90,9 +90,7 @@ addWSGroup :: WSGroupId -> [WorkspaceId] -> X ()
 addWSGroup name wids = withWindowSet $ \w -> do
   let wss  = map ((W.tag . W.workspace) &&& W.screen) $ W.screens w
       wmap = mapM (strength . (flip lookup wss &&& id)) wids
-  case wmap of
-    Just ps -> addRawWSGroup name ps
-    Nothing -> return ()
+  for_ wmap (addRawWSGroup name)
  where strength (ma, b) = ma >>= \a -> return (a,b)
 
 -- | Give a name to the current workspace group.
@@ -114,9 +112,8 @@ viewWSGroup = viewGroup (windows . W.greedyView)
 viewGroup :: (WorkspaceId -> X ()) -> WSGroupId -> X ()
 viewGroup fview name = do
   WSG m <- XS.get
-  case M.lookup name m of
-    Just grp -> mapM_ (uncurry (viewWS fview)) grp
-    Nothing -> return ()
+  for_ (M.lookup name m) $
+    mapM_ (uncurry (viewWS fview))
 
 -- | View the given workspace on the given screen, using the provided function.
 viewWS :: (WorkspaceId -> X ())  -> ScreenId -> WorkspaceId -> X ()
@@ -133,7 +130,7 @@ findScreenWS :: ScreenId -> X (Maybe WorkspaceId)
 findScreenWS sid = withWindowSet $
   return . fmap (W.tag . W.workspace) . find ((==sid) . W.screen) . W.screens
 
-data WSGPrompt = WSGPrompt String
+newtype WSGPrompt = WSGPrompt String
 
 instance XPrompt WSGPrompt where
   showXPrompt (WSGPrompt s) = s

XMonad/Actions/DynamicWorkspaceOrder.hs

@@ -89,7 +89,7 @@ import Data.Ord (comparing)
 -- tweak as desired.
 
 -- | Extensible state storage for the workspace order.
-data WSOrderStorage = WSO { unWSO :: Maybe (M.Map WorkspaceId Int) }
+newtype WSOrderStorage = WSO { unWSO :: Maybe (M.Map WorkspaceId Int) }
   deriving (Typeable, Read, Show)
 
 instance ExtensionClass WSOrderStorage where

XMonad/Actions/DynamicWorkspaces.hs

@@ -86,7 +86,7 @@ type WorkspaceIndex  = Int
 
 -- | Internal dynamic project state that stores a mapping between
 --   workspace indexes and workspace tags.
-data DynamicWorkspaceState = DynamicWorkspaceState {workspaceIndexMap :: Map.Map WorkspaceIndex WorkspaceTag}
+newtype DynamicWorkspaceState = DynamicWorkspaceState {workspaceIndexMap :: Map.Map WorkspaceIndex WorkspaceTag}
   deriving (Typeable, Read, Show)
 
 instance ExtensionClass DynamicWorkspaceState where
@@ -239,14 +239,14 @@ isEmpty t = do wsl <- gets $ workspaces . windowset
                return $ maybe True (isNothing . stack) mws
 
 addHiddenWorkspace' :: (Workspace i l a -> [Workspace i l a] -> [Workspace i l a]) -> i -> l -> StackSet i l a sid sd -> StackSet i l a sid sd
-addHiddenWorkspace' add newtag l s@(StackSet { hidden = ws }) = s { hidden = add (Workspace newtag l Nothing) ws }
+addHiddenWorkspace' add newtag l s@StackSet{ hidden = ws } = s { hidden = add (Workspace newtag l Nothing) ws }
 
 -- | Remove the hidden workspace with the given tag from the StackSet, if
 --   it exists. All the windows in that workspace are moved to the current
 --   workspace.
 removeWorkspace' :: (Eq i) => i -> StackSet i l a sid sd -> StackSet i l a sid sd
-removeWorkspace' torem s@(StackSet { current = scr@(Screen { workspace = wc })
-                                   , hidden = hs })
+removeWorkspace' torem s@StackSet{ current = scr@Screen { workspace = wc }
+                                 , hidden  = hs }
     = let (xs, ys) = break ((== torem) . tag) hs
       in removeWorkspace'' xs ys
    where meld Nothing Nothing = Nothing

XMonad/Actions/FlexibleManipulate.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
 
 -----------------------------------------------------------------------------
 -- |
@@ -23,8 +23,9 @@ module XMonad.Actions.FlexibleManipulate (
 ) where
 
 import XMonad
+import XMonad.Prelude ((<&>))
 import qualified Prelude as P
-import Prelude (($), (.), fst, snd, uncurry, const, id, Ord(..), Monad(..), fromIntegral, Double, Integer, map, round, otherwise)
+import Prelude (Double, Integer, Ord (..), const, fromIntegral, fst, id, map, otherwise, round, snd, uncurry, ($), (.))
 
 -- $usage
 -- First, add this import to your @~\/.xmonad\/xmonad.hs@:
@@ -79,9 +80,9 @@ position = const 0.5
 --   manipulation action.
 mouseWindow :: (Double -> Double) -> Window -> X ()
 mouseWindow f w = whenX (isClient w) $ withDisplay $ \d -> do
-    [wpos, wsize] <- io $ getWindowAttributes d w >>= return . winAttrs
+    [wpos, wsize] <- io $ getWindowAttributes d w <&> winAttrs
     sh <- io $ getWMNormalHints d w
-    pointer <- io $ queryPointer d w >>= return . pointerPos
+    pointer <- io $ queryPointer d w <&> pointerPos
 
     let uv = (pointer - wpos) / wsize
         fc = mapP f uv
@@ -112,7 +113,7 @@ type Pnt = (Double, Double)
 pairUp :: [a] -> [(a,a)]
 pairUp [] = []
 pairUp [_] = []
-pairUp (x:y:xs) = (x, y) : (pairUp xs)
+pairUp (x:y:xs) = (x, y) : pairUp xs
 
 mapP :: (a -> b) -> (a, a) -> (b, b)
 mapP f (x, y) = (f x, f y)
@@ -131,4 +132,3 @@ infixl 7  *, /
 (*) = zipP (P.*)
 (/) :: (P.Fractional a) => (a,a) -> (a,a) -> (a,a)
 (/) = zipP (P./)
-

XMonad/Actions/FlexibleResize.hs

@@ -66,12 +66,12 @@ mouseResizeEdgeWindow edge w = whenX (isClient w) $ withDisplay $ \d -> do
               (float w)
     where
     findPos :: CInt -> Position -> Maybe Bool
-    findPos m s = if p < 0.5 - edge/2
-                  then Just True
-                  else if p < 0.5 + edge/2
-                       then Nothing
-                       else Just False
-                  where p = fi m / fi s
+    findPos m s
+      | p < 0.5 - edge/2 = Just True
+      | p < 0.5 + edge/2 = Nothing
+      | otherwise = Just False
+      where
+          p = fi m / fi s
     mkSel :: Maybe Bool -> Position -> Position -> (Position, Dimension -> Position, Position -> Dimension)
     mkSel b k p = case b of
                       Just True ->  (0, (fi k + fi p -).fi, (fi k + fi p -).fi)

XMonad/Actions/FloatSnap.hs

@@ -27,7 +27,7 @@ module XMonad.Actions.FloatSnap (
                 ifClick') where
 
 import XMonad
-import XMonad.Prelude (fromJust, isNothing, listToMaybe, sort)
+import XMonad.Prelude (fromJust, isNothing, listToMaybe, sort, when)
 import qualified XMonad.StackSet as W
 import qualified Data.Set as S
 
@@ -94,14 +94,14 @@ snapMagicMouseResize
 snapMagicMouseResize middle collidedist snapdist w = whenX (isClient w) $ withDisplay $ \d -> do
     wa <- io $ getWindowAttributes d w
     (_, _, _, px, py, _, _, _) <- io $ queryPointer d w
-    let x = (fromIntegral px - wx wa)/(ww wa)
-        y = (fromIntegral py - wy wa)/(wh wa)
-        ml = if x <= (0.5 - middle/2) then [L] else []
-        mr = if x >  (0.5 + middle/2) then [R] else []
-        mu = if y <= (0.5 - middle/2) then [U] else []
-        md = if y >  (0.5 + middle/2) then [D] else []
+    let x = (fromIntegral px - wx wa)/ww wa
+        y = (fromIntegral py - wy wa)/wh wa
+        ml = [L | x <= (0.5 - middle/2)]
+        mr = [R | x >  (0.5 + middle/2)]
+        mu = [U | y <= (0.5 - middle/2)]
+        md = [D | y >  (0.5 + middle/2)]
         mdir = ml++mr++mu++md
-        dir = if mdir == []
+        dir = if null mdir
               then [L,R,U,D]
               else mdir
     snapMagicResize dir collidedist snapdist w
@@ -124,12 +124,12 @@ snapMagicResize dir collidedist snapdist w = whenX (isClient w) $ withDisplay $
     (xbegin,xend) <- handleAxis True d wa
     (ybegin,yend) <- handleAxis False d wa
 
-    let xbegin' = if L `elem` dir then xbegin else (wx wa)
-        xend'   = if R `elem` dir then xend   else (wx wa + ww wa)
-        ybegin' = if U `elem` dir then ybegin else (wy wa)
-        yend'   = if D `elem` dir then yend   else (wy wa + wh wa)
+    let xbegin' = if L `elem` dir then xbegin else wx wa
+        xend'   = if R `elem` dir then xend   else wx wa + ww wa
+        ybegin' = if U `elem` dir then ybegin else wy wa
+        yend'   = if D `elem` dir then yend   else wy wa + wh wa
 
-    io $ moveWindow d w (fromIntegral $ xbegin') (fromIntegral $ ybegin')
+    io $ moveWindow d w (fromIntegral xbegin') (fromIntegral ybegin')
     io $ resizeWindow d w (fromIntegral $ xend' - xbegin') (fromIntegral $ yend' - ybegin')
     float w
     where
@@ -149,13 +149,13 @@ snapMagicResize dir collidedist snapdist w = whenX (isClient w) $ withDisplay $
                             (Nothing,Nothing) -> wpos wa
                 end = if fs
                       then wpos wa + wdim wa
-                      else case (if mfl==(Just begin) then Nothing else mfl,mfr) of
+                      else case (if mfl==Just begin then Nothing else mfl,mfr) of
                           (Just fl,Just fr) -> if wpos wa + wdim wa - fl < fr - wpos wa - wdim wa then fl else fr
                           (Just fl,Nothing) -> fl
                           (Nothing,Just fr) -> fr
                           (Nothing,Nothing) -> wpos wa + wdim wa
-                begin' = if isNothing snapdist || abs (begin - wpos wa) <= fromJust snapdist then begin else (wpos wa)
-                end' = if isNothing snapdist || abs (end - wpos wa - wdim wa) <= fromJust snapdist then end else (wpos wa + wdim wa)
+                begin' = if isNothing snapdist || abs (begin - wpos wa) <= fromJust snapdist then begin else wpos wa
+                end' = if isNothing snapdist || abs (end - wpos wa - wdim wa) <= fromJust snapdist then end else wpos wa + wdim wa
             return (begin',end')
             where
                 (wpos, wdim, _, _) = constructors horiz
@@ -190,8 +190,8 @@ snapMagicMove collidedist snapdist w = whenX (isClient w) $ withDisplay $ \d ->
                                     (Just fl,Nothing) -> fl
                                     (Nothing,Just fr) -> fr
                                     (Nothing,Nothing) -> wpos wa
-                              newpos = if abs (b - wpos wa) <= abs (f - wpos wa - wdim wa) then b else (f - wdim wa)
-                          in if isNothing snapdist || abs (newpos - wpos wa) <= fromJust snapdist then newpos else (wpos wa)
+                              newpos = if abs (b - wpos wa) <= abs (f - wpos wa - wdim wa) then b else f - wdim wa
+                          in if isNothing snapdist || abs (newpos - wpos wa) <= fromJust snapdist then newpos else wpos wa
             where
                 (wpos, wdim, _, _) = constructors horiz
 
@@ -268,9 +268,8 @@ snapResize grow dir collidedist w = whenX (isClient w) $ withDisplay $ \d -> do
 
     case mr of
         Nothing -> return ()
-        Just (nx,ny,nw,nh) -> if nw>0 && nh>0 then do io $ moveWindow d w (fromIntegral nx) (fromIntegral ny)
+        Just (nx,ny,nw,nh) -> when (nw>0 && nh>0) $ do io $ moveWindow d w (fromIntegral nx) (fromIntegral ny)
                                                        io $ resizeWindow d w (fromIntegral nw) (fromIntegral nh)
-                                              else return ()
     float w
     where
         wx = fromIntegral.wa_x
@@ -286,7 +285,7 @@ getSnap horiz collidedist d w = do
     let sr = screenRect $ W.screenDetail screen
         wl = W.integrate' . W.stack $ W.workspace screen
     gr <- ($sr) <$> calcGap (S.fromList [minBound .. maxBound])
-    wla <- filter (collides wa) <$> (io $ mapM (getWindowAttributes d) $ filter (/=w) wl)
+    wla <- filter (collides wa) <$> io (mapM (getWindowAttributes d) $ filter (/=w) wl)
 
     return ( neighbours (back wa sr gr wla) (wpos wa)
            , neighbours (front wa sr gr wla) (wpos wa + wdim wa)
@@ -300,8 +299,8 @@ getSnap horiz collidedist d w = do
 
         back wa sr gr wla = dropWhile (< rpos sr) $
                             takeWhile (< rpos sr + rdim sr) $
-                            sort $ (rpos sr):(rpos gr):(rpos gr + rdim gr):
-                                   foldr (\a as -> (wpos a):(wpos a + wdim a + wborder a + wborder wa):as) [] wla
+                            sort $ rpos sr:rpos gr:(rpos gr + rdim gr):
+                                   foldr (\a as -> wpos a:(wpos a + wdim a + wborder a + wborder wa):as) [] wla
 
         front wa sr gr wla = dropWhile (<= rpos sr) $
                              takeWhile (<= rpos sr + rdim sr) $
@@ -315,8 +314,8 @@ getSnap horiz collidedist d w = do
 
         collides wa oa = case collidedist of
                              Nothing -> True
-                             Just dist -> (  refwpos oa - wborder oa < refwpos wa + refwdim wa + wborder wa + dist
-                                          && refwpos wa - wborder wa - dist < refwpos oa + refwdim oa + wborder oa )
+                             Just dist -> refwpos oa - wborder oa < refwpos wa + refwdim wa + wborder wa + dist
+                                       && refwpos wa - wborder wa - dist < refwpos oa + refwdim oa + wborder oa
 
 
 constructors :: Bool -> (WindowAttributes -> Int, WindowAttributes -> Int, Rectangle -> Int, Rectangle -> Int)

XMonad/Actions/FocusNth.hs

@@ -39,7 +39,7 @@ focusNth :: Int -> X ()
 focusNth = windows . modify' . focusNth'
 
 focusNth' :: Int -> Stack a -> Stack a
-focusNth' n s@(Stack _ ls rs) | (n < 0) || (n > length(ls) + length(rs)) = s
+focusNth' n s@(Stack _ ls rs) | (n < 0) || (n > length ls + length rs) = s
                               | otherwise = listToStack n (integrate s)
 
 -- | Swap current window with nth. Focus stays in the same position
@@ -52,7 +52,6 @@ swapNth' n s@(Stack c l r)
   | n < length l = let (nl, nc:nr) = splitAt (length l - n - 1) l in Stack nc (nl ++ c : nr) r
   | otherwise    = let (nl, nc:nr) = splitAt (n - length l - 1) r in Stack nc l (nl ++ c : nr)
 
-
 listToStack :: Int -> [a] -> Stack a
 listToStack n l = Stack t ls rs
  where

XMonad/Actions/GridSelect.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE ScopedTypeVariables, GeneralizedNewtypeDeriving, TypeSynonymInstances, FlexibleInstances #-}
+{-# LANGUAGE ScopedTypeVariables, GeneralizedNewtypeDeriving, FlexibleInstances, TupleSections #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Actions.GridSelect
@@ -222,7 +222,7 @@ instance HasColorizer String where
 instance {-# OVERLAPPABLE #-} HasColorizer a where
     defaultColorizer _ isFg =
         let getColor = if isFg then focusedBorderColor else normalBorderColor
-        in asks $ flip (,) "black" . getColor . config
+        in asks $ (, "black") . getColor . config
 
 instance HasColorizer a => Default (GSConfig a) where
     def = buildDefaultGSConfig defaultColorizer
@@ -257,7 +257,7 @@ generateElementmap s = do
     -- Sorts the elementmap
     sortedElements = orderElementmap searchString filteredElements
     -- Case Insensitive version of isInfixOf
-    needle `isInfixOfI` haystack = (upper needle) `isInfixOf` (upper haystack)
+    needle `isInfixOfI` haystack = upper needle `isInfixOf` upper haystack
     upper = map toUpper
 
 
@@ -301,8 +301,8 @@ diamondLayer n =
   -- tr = top right
   --  r = ur ++ 90 degree clock-wise rotation of ur
   let tr = [ (x,n-x) | x <- [0..n-1] ]
-      r  = tr ++ (map (\(x,y) -> (y,-x)) tr)
-  in r ++ (map (negate *** negate) r)
+      r  = tr ++ map (\(x,y) -> (y,-x)) tr
+  in r ++ map (negate *** negate) r
 
 diamond :: (Enum a, Num a, Eq a) => [(a, a)]
 diamond = concatMap diamondLayer [0..]
@@ -332,7 +332,7 @@ drawWinBox win font (fg,bg) bc ch cw text x y cp =
     drawRectangle dpy win bordergc (fromInteger x) (fromInteger y) (fromInteger cw) (fromInteger ch)
   stext <- shrinkWhile (shrinkIt shrinkText)
            (\n -> do size <- liftIO $ textWidthXMF dpy font n
-                     return $ size > (fromInteger (cw-(2*cp))))
+                     return $ size > fromInteger (cw-(2*cp)))
            text
   -- calculate the offset to vertically centre the text based on the ascender and descender
   (asc,desc) <- liftIO $ textExtentsXMF font stext
@@ -385,7 +385,7 @@ updateElementsWithColorizer colorizer elementmap = do
     mapM_ updateElement elementmap
 
 stdHandle :: Event -> TwoD a (Maybe a) -> TwoD a (Maybe a)
-stdHandle (ButtonEvent { ev_event_type = t, ev_x = x, ev_y = y }) contEventloop
+stdHandle ButtonEvent{ ev_event_type = t, ev_x = x, ev_y = y } contEventloop
     | t == buttonRelease = do
         s@TwoDState { td_paneX = px, td_paneY = py,
                          td_gsconfig = (GSConfig ch cw _ _ _ _ _ _ _ _) } <- get
@@ -396,7 +396,7 @@ stdHandle (ButtonEvent { ev_event_type = t, ev_x = x, ev_y = y }) contEventloop
              Nothing -> contEventloop
     | otherwise = contEventloop
 
-stdHandle (ExposeEvent { }) contEventloop = updateAllElements >> contEventloop
+stdHandle ExposeEvent{} contEventloop = updateAllElements >> contEventloop
 
 stdHandle _ contEventloop = contEventloop
 
@@ -443,7 +443,7 @@ setPos newPos = do
       oldPos = td_curpos s
   when (isJust newSelectedEl && newPos /= oldPos) $ do
     put s { td_curpos = newPos }
-    updateElements (catMaybes [(findInElementMap oldPos elmap), newSelectedEl])
+    updateElements (catMaybes [findInElementMap oldPos elmap, newSelectedEl])
 
 -- | Moves the cursor by the offsets specified
 move :: (Integer, Integer) -> TwoD a ()
@@ -543,7 +543,7 @@ navNSearch = makeXEventhandler $ shadowWithKeymap navNSearchKeyMap navNSearchDef
           ,((0,xK_Up)         , move (0,-1) >> navNSearch)
           ,((0,xK_Tab)        , moveNext >> navNSearch)
           ,((shiftMask,xK_Tab), movePrev >> navNSearch)
-          ,((0,xK_BackSpace), transformSearchString (\s -> if (s == "") then "" else init s) >> navNSearch)
+          ,((0,xK_BackSpace), transformSearchString (\s -> if s == "" then "" else init s) >> navNSearch)
           ]
         -- The navigation handler ignores unknown key symbols, therefore we const
         navNSearchDefaultHandler (_,s,_) = do
@@ -557,7 +557,7 @@ substringSearch returnNavigation = fix $ \me ->
   let searchKeyMap = M.fromList [
            ((0,xK_Escape)   , transformSearchString (const "") >> returnNavigation)
           ,((0,xK_Return)   , returnNavigation)
-          ,((0,xK_BackSpace), transformSearchString (\s -> if (s == "") then "" else init s) >> me)
+          ,((0,xK_BackSpace), transformSearchString (\s -> if s == "" then "" else init s) >> me)
           ]
       searchDefaultHandler (_,s,_) = do
           transformSearchString (++ s)
@@ -569,8 +569,8 @@ substringSearch returnNavigation = fix $ \me ->
 -- Conversion scheme as in http://en.wikipedia.org/wiki/HSV_color_space
 hsv2rgb :: Fractional a => (Integer,a,a) -> (a,a,a)
 hsv2rgb (h,s,v) =
-    let hi = (div h 60) `mod` 6 :: Integer
-        f = (((fromInteger h)/60) - (fromInteger hi)) :: Fractional a => a
+    let hi = div h 60 `mod` 6 :: Integer
+        f = ((fromInteger h/60) - fromInteger hi) :: Fractional a => a
         q = v * (1-f)
         p = v * (1-s)
         t = v * (1-(1-f)*s)
@@ -587,19 +587,19 @@ hsv2rgb (h,s,v) =
 stringColorizer :: String -> Bool -> X (String, String)
 stringColorizer s active =
     let seed x = toInteger (sum $ map ((*x).fromEnum) s) :: Integer
-        (r,g,b) = hsv2rgb ((seed 83) `mod` 360,
-                           (fromInteger ((seed 191) `mod` 1000))/2500+0.4,
-                           (fromInteger ((seed 121) `mod` 1000))/2500+0.4)
+        (r,g,b) = hsv2rgb (seed 83 `mod` 360,
+                           fromInteger (seed 191 `mod` 1000)/2500+0.4,
+                           fromInteger (seed 121 `mod` 1000)/2500+0.4)
     in if active
          then return ("#faff69", "black")
-         else return ("#" ++ concat (map (twodigitHex.(round :: Double -> Word8).(*256)) [r, g, b] ), "white")
+         else return ("#" ++ concatMap (twodigitHex.(round :: Double -> Word8).(*256)) [r, g, b], "white")
 
 -- | Colorize a window depending on it's className.
 fromClassName :: Window -> Bool -> X (String, String)
 fromClassName w active = runQuery className w >>= flip defaultColorizer active
 
 twodigitHex :: Word8 -> String
-twodigitHex a = printf "%02x" a
+twodigitHex = printf "%02x"
 
 -- | A colorizer that picks a color inside a range,
 -- and depending on the window's class.
@@ -655,14 +655,14 @@ gridselect gsconfig elements =
     font <- initXMF (gs_font gsconfig)
     let screenWidth = toInteger $ rect_width scr
         screenHeight = toInteger $ rect_height scr
-    selectedElement <- if (status == grabSuccess) then do
+    selectedElement <- if status == grabSuccess then do
                             let restriction ss cs = (fromInteger ss/fromInteger (cs gsconfig)-1)/2 :: Double
                                 restrictX = floor $ restriction screenWidth gs_cellwidth
                                 restrictY = floor $ restriction screenHeight gs_cellheight
-                                originPosX = floor $ ((gs_originFractX gsconfig) - (1/2)) * 2 * fromIntegral restrictX
-                                originPosY = floor $ ((gs_originFractY gsconfig) - (1/2)) * 2 * fromIntegral restrictY
+                                originPosX = floor $ (gs_originFractX gsconfig - (1/2)) * 2 * fromIntegral restrictX
+                                originPosY = floor $ (gs_originFractY gsconfig - (1/2)) * 2 * fromIntegral restrictY
                                 coords = diamondRestrict restrictX restrictY originPosX originPosY
-                                s = TwoDState { td_curpos = (head coords),
+                                s = TwoDState { td_curpos = head coords,
                                                 td_availSlots = coords,
                                                 td_elements = elements,
                                                 td_gsconfig = gsconfig,
@@ -673,7 +673,7 @@ gridselect gsconfig elements =
                                                 td_searchString = "",
                                                 td_elementmap = [] }
                             m <- generateElementmap s
-                            evalTwoD (updateAllElements >> (gs_navigate gsconfig))
+                            evalTwoD (updateAllElements >> gs_navigate gsconfig)
                                      (s { td_elementmap = m })
                       else
                           return Nothing
@@ -695,16 +695,13 @@ gridselectWindow gsconf = windowMap >>= gridselect gsconf
 withSelectedWindow :: (Window -> X ()) -> GSConfig Window -> X ()
 withSelectedWindow callback conf = do
     mbWindow <- gridselectWindow conf
-    case mbWindow of
-        Just w -> callback w
-        Nothing -> return ()
+    for_ mbWindow callback
 
 windowMap :: X [(String,Window)]
 windowMap = do
     ws <- gets windowset
-    wins <- mapM keyValuePair (W.allWindows ws)
-    return wins
- where keyValuePair w = flip (,) w <$> decorateName' w
+    mapM keyValuePair (W.allWindows ws)
+ where keyValuePair w = (, w) <$> decorateName' w
 
 decorateName' :: Window -> X String
 decorateName' w = do
@@ -782,7 +779,7 @@ noRearranger _ = return
 -- already present).
 searchStringRearrangerGenerator :: (String -> a) -> Rearranger a
 searchStringRearrangerGenerator f =
-    let r "" xs                       = return $ xs
-        r s  xs | s `elem` map fst xs = return $ xs
+    let r "" xs                       = return xs
+        r s  xs | s `elem` map fst xs = return xs
                 | otherwise           = return $ xs ++ [(s, f s)]
     in r

XMonad/Actions/GroupNavigation.hs

@@ -224,5 +224,5 @@ isOnAnyVisibleWS = do
   ws <- liftX $ gets windowset
   let allVisible = concat $ maybe [] SS.integrate . SS.stack . SS.workspace <$> SS.current ws:SS.visible ws
       visibleWs = w `elem` allVisible
-      unfocused = maybe True (w /=) $ SS.peek ws
+      unfocused = Just w /= SS.peek ws
   return $ visibleWs && unfocused

XMonad/Actions/KeyRemap.hs

@@ -33,7 +33,7 @@ import XMonad.Util.Paste
 import qualified XMonad.Util.ExtensibleState as XS
 
 
-data KeymapTable = KeymapTable [((KeyMask, KeySym), (KeyMask, KeySym))] deriving (Typeable, Show)
+newtype KeymapTable = KeymapTable [((KeyMask, KeySym), (KeyMask, KeySym))] deriving (Typeable, Show)
 
 instance ExtensionClass KeymapTable where
    initialValue = KeymapTable []
@@ -124,8 +124,8 @@ extractKeyMapping (KeymapTable table) mask sym =
 buildKeyRemapBindings :: [KeymapTable] -> [((KeyMask, KeySym), X ())]
 buildKeyRemapBindings keyremaps =
   [((mask, sym), doKeyRemap mask sym) | (mask, sym) <- bindings]
-  where mappings = concat (map (\(KeymapTable table) -> table) keyremaps)
-        bindings = nub (map (\binding -> fst binding) mappings)
+  where mappings = concatMap (\(KeymapTable table) -> table) keyremaps
+        bindings = nub (map fst mappings)
 
 
 -- Here come the Keymappings
@@ -137,7 +137,7 @@ emptyKeyRemap = KeymapTable []
 dvorakProgrammerKeyRemap :: KeymapTable
 dvorakProgrammerKeyRemap =
   KeymapTable [((charToMask maskFrom, from), (charToMask maskTo, to)) |
-               (maskFrom, from, maskTo, to) <- (zip4 layoutUsShift layoutUsKey layoutDvorakShift layoutDvorakKey)]
+               (maskFrom, from, maskTo, to) <- zip4 layoutUsShift layoutUsKey layoutDvorakShift layoutDvorakKey]
   where
 
     layoutUs    = map (fromIntegral . fromEnum) "`1234567890-=qwertyuiop[]\\asdfghjkl;'zxcvbnm,./~!@#$%^&*()_+QWERTYUIOP{}|ASDFGHJKL:\"ZXCVBNM<>?"  :: [KeySym]

XMonad/Actions/Launcher.hs

@@ -61,7 +61,7 @@ type ExtensionActions = M.Map String (String -> X())
 instance XPrompt CalculatorMode where
   showXPrompt CalcMode = "calc %s> "
   commandToComplete CalcMode = id --send the whole string to `calc`
-  completionFunction CalcMode = \s -> if (length s == 0) then return [] else
+  completionFunction CalcMode = \s -> if null s then return [] else
     lines <$> runProcessWithInput "calc" [s] ""
   modeAction CalcMode _ _ = return () -- do nothing; this might copy the result to the clipboard
 

XMonad/Actions/LinkWorkspaces.hs

@@ -27,6 +27,7 @@ module XMonad.Actions.LinkWorkspaces (
                                        ) where
 
 import XMonad
+import XMonad.Prelude (for_)
 import qualified XMonad.StackSet as W
 import XMonad.Layout.IndependentScreens(countScreens)
 import qualified XMonad.Util.ExtensibleState as XS (get, put)
@@ -59,7 +60,7 @@ import qualified Data.Map as M
 -- For detailed instructions on editing your key bindings, see
 -- "XMonad.Doc.Extending#Editing_key_bindings".
 
-data MessageConfig = MessageConfig {  messageFunction :: (ScreenId -> [Char] -> [Char] -> [Char] -> X())
+data MessageConfig = MessageConfig {  messageFunction :: ScreenId -> [Char] -> [Char] -> [Char] -> X()
                     , foreground :: [Char]
                     , alertedForeground :: [Char]
                     , background :: [Char]
@@ -75,7 +76,7 @@ noMessageFn :: ScreenId -> [Char] -> [Char] -> [Char] -> X()
 noMessageFn _ _ _ _ = return () :: X ()
 
 -- | Stuff for linking workspaces
-data WorkspaceMap = WorkspaceMap (M.Map WorkspaceId WorkspaceId) deriving (Read, Show, Typeable)
+newtype WorkspaceMap = WorkspaceMap (M.Map WorkspaceId WorkspaceId) deriving (Read, Show, Typeable)
 instance ExtensionClass WorkspaceMap
     where initialValue = WorkspaceMap M.empty
           extensionType = PersistentExtension
@@ -85,12 +86,12 @@ switchWS f m ws = switchWS' f m ws Nothing
 
 -- | Switch to the given workspace in a non greedy way, stop if we reached the first screen
 -- | we already did switching on
-switchWS' :: (WorkspaceId -> X ()) -> MessageConfig  -> WorkspaceId -> (Maybe ScreenId) -> X ()
+switchWS' :: (WorkspaceId -> X ()) -> MessageConfig  -> WorkspaceId -> Maybe ScreenId -> X ()
 switchWS' switchFn message workspace stopAtScreen = do
   ws <- gets windowset
   nScreens <- countScreens
   let now = W.screen (W.current ws)
-  let next = ((now + 1) `mod` nScreens)
+  let next = (now + 1) `mod` nScreens
   switchFn workspace
   case stopAtScreen of
     Nothing -> sTM now next (Just now)
@@ -99,11 +100,11 @@ switchWS' switchFn message workspace stopAtScreen = do
 
 -- | Switch to the workspace that matches the current one, executing switches for that workspace as well.
 -- | The function switchWorkspaceNonGreedy' will take of stopping if we reached the first workspace again.
-switchToMatching :: (WorkspaceId -> (Maybe ScreenId) -> X ()) -> MessageConfig -> WorkspaceId -> ScreenId 
-    -> ScreenId -> (Maybe ScreenId) -> X ()
+switchToMatching :: (WorkspaceId -> Maybe ScreenId -> X ()) -> MessageConfig -> WorkspaceId -> ScreenId
+    -> ScreenId -> Maybe ScreenId -> X ()
 switchToMatching f message t now next stopAtScreen = do
     WorkspaceMap matchings <- XS.get :: X WorkspaceMap
-    case (M.lookup t matchings) of
+    case M.lookup t matchings of
         Nothing -> return () :: X()
         Just newWorkspace -> do
             onScreen' (f newWorkspace stopAtScreen) FocusCurrent next
@@ -113,7 +114,7 @@ switchToMatching f message t now next stopAtScreen = do
 toggleMatching :: MessageConfig -> WorkspaceId -> WorkspaceId -> X ()
 toggleMatching message t1 t2 = do
     WorkspaceMap matchings <- XS.get :: X WorkspaceMap
-    case (M.lookup t1 matchings) of
+    case M.lookup t1 matchings of
         Nothing -> setMatching message t1 t2 matchings
         Just t -> if t == t2 then removeMatching' message t1 t2 matchings else setMatching message t1 t2 matchings
     return ()
@@ -142,7 +143,7 @@ removeAllMatchings :: MessageConfig -> X ()
 removeAllMatchings message = do
    ws <- gets windowset
    let now = W.screen (W.current ws)
-   XS.put $ WorkspaceMap $ M.empty
+   XS.put $ WorkspaceMap M.empty
    messageFunction message now (alertedForeground message) (background message) "All links removed!"
 
 -- | remove all matching regarding a given workspace
@@ -163,7 +164,6 @@ toggleLinkWorkspaces' first message = do
     let now = W.screen (W.current ws)
     let next = (now + 1) `mod` nScreens
     if next == first then return () else do -- this is also the case if there is only one screen
-        case (W.lookupWorkspace next ws) of
-            Nothing -> return ()
-            Just name -> toggleMatching message (W.currentTag ws) (name)
+        for_ (W.lookupWorkspace next ws)
+             (toggleMatching message (W.currentTag ws))
         onScreen' (toggleLinkWorkspaces' first message) FocusCurrent next

XMonad/Actions/MessageFeedback.hs

@@ -106,7 +106,7 @@ import Control.Monad.State  ( gets )
 -- 'XMonad.Operations.sendMessage' code - foregoes the O(n) 'updateLayout'.
 sendSomeMessageB :: SomeMessage -> X Bool
 sendSomeMessageB m = windowBracket id $ do
-    w  <- workspace . current <$> gets windowset
+    w  <- gets ((workspace . current) . windowset)
     ml <- handleMessage (layout w) m `catchX` return Nothing
     whenJust ml $ \l ->
         modifyWindowSet $ \ws -> ws { current = (current ws)
@@ -138,7 +138,7 @@ sendSomeMessageWithNoRefresh m = void . sendSomeMessageWithNoRefreshB m
 -- 'XMonad.Operations.sendMessageWithNoRefresh' (does not refresh).
 sendSomeMessageWithNoRefreshToCurrentB :: SomeMessage -> X Bool
 sendSomeMessageWithNoRefreshToCurrentB m
-    =   (gets $ workspace . current . windowset)
+    =   gets (workspace . current . windowset)
     >>= sendSomeMessageWithNoRefreshB m
 
 -- | Variant of 'sendSomeMessageWithNoRefreshToCurrentB' that discards the

XMonad/Actions/Minimize.hs

@@ -118,7 +118,7 @@ maximizeWindowAndFocus = maximizeWindowAndChangeWSet W.focusWindow
 -- | Perform an action with first minimized window on current workspace
 --   or do nothing if there is no minimized windows on current workspace
 withFirstMinimized :: (Window -> X ()) -> X ()
-withFirstMinimized action = withFirstMinimized' (flip whenJust action)
+withFirstMinimized action = withFirstMinimized' (`whenJust` action)
 
 -- | Like withFirstMinimized but the provided action is always invoked with a
 --   'Maybe Window', that will be nothing if there is no first minimized window.
@@ -128,7 +128,7 @@ withFirstMinimized' action = withMinimized (action . listToMaybe . reverse)
 -- | Perform an action with last minimized window on current workspace
 --   or do nothing if there is no minimized windows on current workspace
 withLastMinimized :: (Window -> X ()) -> X ()
-withLastMinimized action = withLastMinimized' (flip whenJust action)
+withLastMinimized action = withLastMinimized' (`whenJust` action)
 
 -- | Like withLastMinimized but the provided action is always invoked with a
 --   'Maybe Window', that will be nothing if there is no last minimized window.

XMonad/Actions/MouseGestures.hs

@@ -110,7 +110,7 @@ mouseGestureH moveHook endHook = do
 mouseGesture :: Map [Direction2D] (Window -> X ()) -> Window -> X ()
 mouseGesture tbl win = do
     (mov, end) <- mkCollect
-    mouseGestureH (\d -> mov d >> return ()) $ end >>= \gest ->
+    mouseGestureH (void . mov) $ end >>= \gest ->
         case M.lookup gest tbl of
             Nothing -> return ()
             Just f -> f win

XMonad/Actions/MouseResize.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE GeneralizedNewtypeDeriving, MultiParamTypeClasses, PatternGuards, TypeSynonymInstances #-}
+{-# LANGUAGE MultiParamTypeClasses, PatternGuards, TypeSynonymInstances #-}
 
 -----------------------------------------------------------------------------
 -- |
@@ -56,7 +56,7 @@ import XMonad.Util.XUtils
 mouseResize :: l a -> ModifiedLayout MouseResize l a
 mouseResize = ModifiedLayout (MR [])
 
-data MouseResize a = MR [((a,Rectangle),Maybe a)]
+newtype MouseResize a = MR [((a,Rectangle),Maybe a)]
 instance Show (MouseResize a) where show        _ = ""
 instance Read (MouseResize a) where readsPrec _ s = [(MR [], s)]
 
@@ -68,7 +68,7 @@ instance LayoutModifier MouseResize Window where
         where
           wrs'         = wrs_to_state [] . filter (isInStack s . fst) $ wrs
           initState    = mapM createInputWindow wrs'
-          processState = mapM (deleteInputWin . snd) st >> mapM createInputWindow wrs'
+          processState = mapM_ (deleteInputWin . snd) st >> mapM createInputWindow wrs'
 
           inputRectangle (Rectangle x y wh ht) = Rectangle (x + fi wh - 5) (y + fi ht - 5) 10 10
 

XMonad/Actions/Navigation2D.hs

@@ -59,7 +59,7 @@ module XMonad.Actions.Navigation2D ( -- * Usage
 
 import qualified Data.List as L
 import qualified Data.Map as M
-import Data.Ord (comparing)
+import Control.Arrow (second)
 import XMonad.Prelude
 import XMonad hiding (Screen)
 import qualified XMonad.StackSet as W
@@ -476,7 +476,7 @@ switchLayer = actOnLayer otherLayer
 -- navigation should wrap around (e.g., from the left edge of the leftmost
 -- screen to the right edge of the rightmost screen).
 windowGo :: Direction2D -> Bool -> X ()
-windowGo dir wrap = actOnLayer thisLayer
+windowGo dir = actOnLayer thisLayer
                                ( \ conf cur wins -> windows
                                  $ doTiledNavigation conf dir W.focusWindow cur wins
                                )
@@ -486,7 +486,6 @@ windowGo dir wrap = actOnLayer thisLayer
                                ( \ conf cur wspcs -> windows
                                  $ doScreenNavigation conf dir W.view cur wspcs
                                )
-                               wrap
 
 -- | Swaps the current window with the next window in the given direction and in
 -- the same layer as the current window.  (In the floating layer, all that
@@ -495,7 +494,7 @@ windowGo dir wrap = actOnLayer thisLayer
 -- window's screen but retains its position and size relative to the screen.)
 -- The second argument indicates wrapping (see 'windowGo').
 windowSwap :: Direction2D -> Bool -> X ()
-windowSwap dir wrap = actOnLayer thisLayer
+windowSwap dir = actOnLayer thisLayer
                                  ( \ conf cur wins -> windows
                                    $ doTiledNavigation conf dir swap cur wins
                                  )
@@ -503,32 +502,28 @@ windowSwap dir wrap = actOnLayer thisLayer
                                    $ doFloatNavigation conf dir swap cur wins
                                  )
                                  ( \ _ _ _ -> return () )
-                                 wrap
 
 -- | Moves the current window to the next screen in the given direction.  The
 -- second argument indicates wrapping (see 'windowGo').
 windowToScreen :: Direction2D -> Bool -> X ()
-windowToScreen dir wrap = actOnScreens ( \ conf cur wspcs -> windows
+windowToScreen dir = actOnScreens ( \ conf cur wspcs -> windows
                                          $ doScreenNavigation conf dir W.shift cur wspcs
                                        )
-                                       wrap
 
 -- | Moves the focus to the next screen in the given direction.  The second
 -- argument indicates wrapping (see 'windowGo').
 screenGo :: Direction2D -> Bool -> X ()
-screenGo dir wrap = actOnScreens ( \ conf cur wspcs -> windows
+screenGo dir = actOnScreens ( \ conf cur wspcs -> windows
                                    $ doScreenNavigation conf dir W.view cur wspcs
                                  )
-                                 wrap
 
 -- | Swaps the workspace on the current screen with the workspace on the screen
 -- in the given direction.  The second argument indicates wrapping (see
 -- 'windowGo').
 screenSwap :: Direction2D -> Bool -> X ()
-screenSwap dir wrap = actOnScreens ( \ conf cur wspcs -> windows
+screenSwap dir = actOnScreens ( \ conf cur wspcs -> windows
                                      $ doScreenNavigation conf dir W.greedyView cur wspcs
                                    )
-                                   wrap
 
 -- | Maps each window to a fullscreen rect.  This may not be the same rectangle the
 -- window maps to under the Full layout or a similar layout if the layout
@@ -648,7 +643,7 @@ doFocusClosestWindow (cur, rect) winrects
   where
     ctr     = centerOf rect
     winctrs = filter ((cur /=) . fst)
-            $ map (\(w, r) -> (w, centerOf r)) winrects
+            $ map (second centerOf) winrects
     closer wc1@(_, c1) wc2@(_, c2) | lDist ctr c1 > lDist ctr c2 = wc2
                                    | otherwise                   = wc1
 
@@ -668,8 +663,7 @@ doTiledNavigation conf dir act cur winrects winset
     nav     = maximum
             $ map ( fromMaybe (defaultTiledNavigation conf)
                   . flip L.lookup (layoutNavigation conf)
-                  )
-            $ layouts
+                  ) layouts
 
 -- | Implements navigation for the float layer
 doFloatNavigation :: Navigation2DConfig
@@ -714,7 +708,7 @@ doLineNavigation dir (cur, rect) winrects
 
     -- The list of windows that are candidates to receive focus.
     winrects'     = filter dirFilter
-                  $ filter ((cur /=) . fst)
+                  . filter ((cur /=) . fst)
                   $ winrects
 
     -- Decides whether a given window matches the criteria to be a candidate to
@@ -755,9 +749,8 @@ doCenterNavigation dir (cur, rect) winrects
     -- center rotated so the right cone becomes the relevant cone.
     -- The windows are ordered in the order they should be preferred
     -- when they are otherwise tied.
-    winctrs = map (\(w, r) -> (w, dirTransform . centerOf $ r))
-            $ stackTransform
-            $ winrects
+    winctrs = map (second (dirTransform . centerOf))
+            $ stackTransform winrects
 
     -- Give preference to windows later in the stack for going left or up and to
     -- windows earlier in the stack for going right or down.  (The stack order
@@ -815,7 +808,7 @@ doSideNavigationWithBias ::
   Eq a => Int -> Direction2D -> Rect a -> [Rect a] -> Maybe a
 doSideNavigationWithBias bias dir (cur, rect)
   = fmap fst . listToMaybe
-  . L.sortBy (comparing dist) . foldr acClosest []
+  . L.sortOn dist . foldr acClosest []
   . filter (`toRightOf` (cur, transform rect))
   . map (fmap transform)
   where
@@ -843,7 +836,7 @@ doSideNavigationWithBias bias dir (cur, rect)
     -- Greedily accumulate the windows tied for the leftmost left side.
     acClosest (w, r) l@((_, r'):_) | x1 r == x1 r' = (w, r) : l
                                    | x1 r >  x1 r' =          l
-    acClosest (w, r) _                             = (w, r) : []
+    acClosest (w, r) _                             = [(w, r)]
 
     -- Given a (_, SideRect), calculate how far it is from the y=bias line.
     dist (_, r) | (y1 r <= bias) && (bias <= y2 r) = 0
@@ -864,7 +857,7 @@ swap win winset = W.focusWindow cur
     visws    = map W.workspace scrs
 
     -- The focused windows of the visible workspaces
-    focused  = mapMaybe (\ws -> W.focus <$> W.stack ws) visws
+    focused  = mapMaybe (fmap W.focus . W.stack) visws
 
     -- The window lists of the visible workspaces
     wins     = map (W.integrate' . W.stack) visws
@@ -891,8 +884,8 @@ centerOf r = (rect_x r + fi (rect_width r) `div` 2, rect_y r + fi (rect_height r
 
 -- | Functions to choose the subset of windows to operate on
 thisLayer, otherLayer :: a -> a -> a
-thisLayer  = curry fst
-otherLayer = curry snd
+thisLayer  = const
+otherLayer _ x = x
 
 -- | Returns the list of visible workspaces and their screen rects
 visibleWorkspaces :: WindowSet -> Bool -> [WSRect]
@@ -929,8 +922,8 @@ wrapOffsets winset = (max_x - min_x, max_y - min_y)
   where
     min_x = fi $ minimum $ map rect_x rects
     min_y = fi $ minimum $ map rect_y rects
-    max_x = fi $ maximum $ map (\r -> rect_x r + (fi $ rect_width  r)) rects
-    max_y = fi $ maximum $ map (\r -> rect_y r + (fi $ rect_height r)) rects
+    max_x = fi $ maximum $ map (\r -> rect_x r + fi (rect_width  r)) rects
+    max_y = fi $ maximum $ map (\r -> rect_y r + fi (rect_height r)) rects
     rects = map snd $ visibleWorkspaces winset False
 
 

XMonad/Actions/PhysicalScreens.hs

@@ -30,7 +30,7 @@ module XMonad.Actions.PhysicalScreens (
                                       ) where
 
 import XMonad
-import XMonad.Prelude (findIndex, on, sortBy)
+import XMonad.Prelude (elemIndex, fromMaybe, on, sortBy)
 import qualified XMonad.StackSet as W
 
 {- $usage
@@ -70,7 +70,7 @@ For detailed instructions on editing your key bindings, see
 -- | The type of the index of a screen by location
 newtype PhysicalScreen = P Int deriving (Eq,Ord,Show,Read,Enum,Num,Integral,Real)
 
-getScreenIdAndRectangle :: (W.Screen i l a ScreenId ScreenDetail) -> (ScreenId, Rectangle)
+getScreenIdAndRectangle :: W.Screen i l a ScreenId ScreenDetail -> (ScreenId, Rectangle)
 getScreenIdAndRectangle screen = (W.screen screen, rect) where
   rect = screenRect $ W.screenDetail screen
 
@@ -129,7 +129,7 @@ getNeighbour :: ScreenComparator -> Int -> X ScreenId
 getNeighbour (ScreenComparator cmpScreen) d =
   do w <- gets windowset
      let ss = map W.screen $ sortBy (cmpScreen `on` getScreenIdAndRectangle) $ W.current w : W.visible w
-         curPos = maybe 0 id $ findIndex (== W.screen (W.current w)) ss
+         curPos = fromMaybe 0 $ elemIndex (W.screen (W.current w)) ss
          pos = (curPos + d) `mod` length ss
      return $ ss !! pos
 

XMonad/Actions/Prefix.hs

@@ -140,7 +140,7 @@ usePrefixArgument prefix conf = conf {
 useDefaultPrefixArgument :: LayoutClass l Window
                          => XConfig l
                          -> XConfig l
-useDefaultPrefixArgument = usePrefixArgument (\_ -> (controlMask, xK_u))
+useDefaultPrefixArgument = usePrefixArgument (const (controlMask, xK_u))
 
 handlePrefixArg :: [(KeyMask, KeySym)] -> X ()
 handlePrefixArg events = do

XMonad/Actions/RotSlaves.hs

@@ -40,8 +40,8 @@ import XMonad
 -- | Rotate the windows in the current stack, excluding the first one
 --   (master).
 rotSlavesUp,rotSlavesDown :: X ()
-rotSlavesUp   = windows $ modify' (rotSlaves' (\l -> (tail l)++[head l]))
-rotSlavesDown = windows $ modify' (rotSlaves' (\l -> [last l]++(init l)))
+rotSlavesUp   = windows $ modify' (rotSlaves' (\l -> tail l++[head l]))
+rotSlavesDown = windows $ modify' (rotSlaves' (\l -> last l : init l))
 
 -- | The actual rotation, as a pure function on the window stack.
 rotSlaves' :: ([a] -> [a]) -> Stack a -> Stack a
@@ -49,12 +49,12 @@ rotSlaves' _ s@(Stack _ [] []) = s
 rotSlaves' f   (Stack t [] rs) = Stack t [] (f rs)                -- Master has focus
 rotSlaves' f s@(Stack _ ls _ ) = Stack t' (reverse revls') rs'    -- otherwise
     where  (master:ws)     = integrate s
-           (revls',t':rs') = splitAt (length ls) (master:(f ws))
+           (revls',t':rs') = splitAt (length ls) (master:f ws)
 
 -- | Rotate all the windows in the current stack.
 rotAllUp,rotAllDown :: X ()
-rotAllUp   = windows $ modify' (rotAll' (\l -> (tail l)++[head l]))
-rotAllDown = windows $ modify' (rotAll' (\l -> [last l]++(init l)))
+rotAllUp   = windows $ modify' (rotAll' (\l -> tail l++[head l]))
+rotAllDown = windows $ modify' (rotAll' (\l -> last l : init l))
 
 -- | The actual rotation, as a pure function on the window stack.
 rotAll' :: ([a] -> [a]) -> Stack a -> Stack a

XMonad/Actions/RotateSome.hs

@@ -152,8 +152,7 @@ rotateSome p (Stack t ls rs) =
         . span ((< 0) . fst)
         . sortOn fst
         . (++) anchors
-        . map (fst *** snd)
-        $ zip movables (rotate movables)
+        $ zipWith (curry (fst *** snd)) movables (rotate movables)
   in
     Stack t' (reverse ls') rs'
 

XMonad/Actions/Search.hs

@@ -213,7 +213,7 @@ engine.
 Happy searching! -}
 
 -- | A customized prompt indicating we are searching, and the name of the site.
-data Search = Search Name
+newtype Search = Search Name
 instance XPrompt Search where
     showXPrompt (Search name)= "Search [" ++ name ++ "]: "
     nextCompletion _ = getNextCompletion
@@ -260,7 +260,7 @@ search browser site query = safeSpawn browser [site query]
    Generally, examining the resultant URL of a search will allow you to reverse-engineer
    it if you can't find the necessary URL already described in other projects such as Surfraw. -}
 searchEngine :: Name -> String -> SearchEngine
-searchEngine name site = searchEngineF name (\s -> site ++ (escape s))
+searchEngine name site = searchEngineF name (\s -> site ++ escape s)
 
 {- | If your search engine is more complex than this (you may want to identify
    the kind of input and make the search URL dependent on the input or put the query
@@ -316,7 +316,7 @@ vocabulary    = searchEngine "vocabulary"    "http://www.vocabulary.com/search?q
 duckduckgo    = searchEngine "duckduckgo"    "https://duckduckgo.com/?t=lm&q="
 
 multi :: SearchEngine
-multi = namedEngine "multi" $ foldr1 (!>) [amazon, alpha, codesearch, deb, debbts, debpts, dictionary, ebay, google, hackage, hoogle, images, imdb, isohunt, lucky, maps, mathworld, openstreetmap, scholar, thesaurus, wayback, wikipedia, wiktionary, duckduckgo, (prefixAware google)]
+multi = namedEngine "multi" $ foldr1 (!>) [amazon, alpha, codesearch, deb, debbts, debpts, dictionary, ebay, google, hackage, hoogle, images, imdb, isohunt, lucky, maps, mathworld, openstreetmap, scholar, thesaurus, wayback, wikipedia, wiktionary, duckduckgo, prefixAware google]
 
 {- | This function wraps up a search engine and creates a new one, which works
    like the argument, but goes directly to a URL if one is given rather than
@@ -326,7 +326,7 @@ multi = namedEngine "multi" $ foldr1 (!>) [amazon, alpha, codesearch, deb, debbt
 
    Now if you search for http:\/\/xmonad.org it will directly open in your browser-}
 intelligent :: SearchEngine -> SearchEngine
-intelligent (SearchEngine name site) = searchEngineF name (\s -> if (fst $ break (==':') s) `elem` ["http", "https", "ftp"] then s else (site s))
+intelligent (SearchEngine name site) = searchEngineF name (\s -> if takeWhile (/= ':') s `elem` ["http", "https", "ftp"] then s else site s)
 
 -- | > removeColonPrefix "foo://bar" ~> "//bar"
 -- > removeColonPrefix "foo//bar" ~> "foo//bar"

XMonad/Actions/ShowText.hs

@@ -87,8 +87,8 @@ handleTimerEvent :: Event -> X All
 handleTimerEvent (ClientMessageEvent _ _ _ dis _ mtyp d) = do
     (ShowText m) <- ES.get :: X ShowText
     a <- io $ internAtom dis "XMONAD_TIMER" False
-    when (mtyp == a && length d >= 1)
-         (whenJust (lookup (fromIntegral $ d !! 0) m) deleteWindow)
+    when (mtyp == a && not (null d))
+         (whenJust (lookup (fromIntegral $ head d) m) deleteWindow)
     mempty
 handleTimerEvent _ = mempty
 

XMonad/Actions/SpawnOn.hs

@@ -124,7 +124,7 @@ manageSpawnWithGC garbageCollect = do
 
 mkPrompt :: (String -> X ()) -> XPConfig -> X ()
 mkPrompt cb c = do
-    cmds <- io $ getCommands
+    cmds <- io getCommands
     mkXPrompt Shell c (getShellCompl cmds $ searchPredicate c) cb
 
 -- | Replacement for Shell prompt ("XMonad.Prompt.Shell") which launches
@@ -145,13 +145,13 @@ spawnHere cmd = withWindowSet $ \ws -> spawnOn (W.currentTag ws) cmd
 -- | Replacement for 'spawn' which launches
 -- application on given workspace.
 spawnOn :: WorkspaceId -> String -> X ()
-spawnOn ws cmd = spawnAndDo (doShift ws) cmd
+spawnOn ws = spawnAndDo (doShift ws)
 
 -- | Spawn an application and apply the manage hook when it opens.
 spawnAndDo :: ManageHook -> String -> X ()
 spawnAndDo mh cmd = do
     p <- spawnPID $ mangle cmd
-    modifySpawner $ ((p,mh) :)
+    modifySpawner ((p,mh) :)
  where
     -- TODO this is silly, search for a better solution
     mangle xs | any (`elem` metaChars) xs || "exec" `isInfixOf` xs = xs

XMonad/Actions/SwapPromote.hs

@@ -338,7 +338,7 @@ split' p i l =
             then (c+1,e:ys,ns)
             else (c+1,ys,e:ns)
         (c',ys',ns') = foldr accumulate (0,[],[]) $ zip [i..] l
-    in  (c',ys',snd . unzip $ ns')
+    in  (c',ys',map snd ns')
 
 -- | Wrap 'merge'' with an initial virtual index of @0@. Return only the
 -- unindexed list with elements from the leftover indexed list appended.

XMonad/Actions/SwapWorkspaces.hs

@@ -59,6 +59,7 @@ swapTo dir = findWorkspace getSortByIndex dir AnyWS 1 >>= windows . swapWithCurr
 --   one with the two corresponding workspaces' tags swapped.
 swapWorkspaces :: Eq i => i -> i -> StackSet i l a s sd -> StackSet i l a s sd
 swapWorkspaces t1 t2 = mapWorkspace swap
-    where swap w = if      tag w == t1 then w { tag = t2 }
-                   else if tag w == t2 then w { tag = t1 }
-                   else w
+    where swap w
+            | tag w == t1 = w { tag = t2 }
+            | tag w == t2 = w { tag = t1 }
+            | otherwise = w

XMonad/Actions/TagWindows.hs

@@ -82,8 +82,7 @@ getTags w = withDisplay $ \d ->
     io $ E.catch (internAtom d "_XMONAD_TAGS" False >>=
                 getTextProperty d w >>=
                 wcTextPropertyToTextList d)
-               (econst [[]])
-    >>= return . words . unwords
+               (econst [[]]) <&> (words . unwords)
 
 -- | check a window for the given tag
 hasTag :: String -> Window -> X Bool
@@ -93,7 +92,7 @@ hasTag s w = (s `elem`) <$> getTags w
 addTag :: String -> Window -> X ()
 addTag s w = do
     tags <- getTags w
-    if (s `notElem` tags) then setTags (s:tags) w else return ()
+    when (s `notElem` tags) $ setTags (s:tags) w
 
 -- | remove a tag from a window, if it exists
 delTag :: String -> Window -> X ()
@@ -156,7 +155,7 @@ withTagged' t m = gets windowset >>= filterM (hasTag t) . index >>= m
 
 withTaggedGlobal' :: String -> ([Window] -> X ()) -> X ()
 withTaggedGlobal' t m = gets windowset >>=
-    filterM (hasTag t) . concat . map (integrate' . stack) . workspaces >>= m
+    filterM (hasTag t) . concatMap (integrate' . stack) . workspaces >>= m
 
 withFocusedP :: (Window -> WindowSet -> WindowSet) -> X ()
 withFocusedP f = withFocused $ windows . f
@@ -165,7 +164,7 @@ shiftHere :: (Ord a, Eq s, Eq i) => a -> StackSet i l a s sd -> StackSet i l a s
 shiftHere w s = shiftWin (currentTag s) w s
 
 shiftToScreen :: (Ord a, Eq s, Eq i) => s -> a -> StackSet i l a s sd -> StackSet i l a s sd
-shiftToScreen sid w s = case filter (\m -> sid /= screen m) ((current s):(visible s)) of
+shiftToScreen sid w s = case filter (\m -> sid /= screen m) (current s:visible s) of
                                 []      -> s
                                 (t:_)   -> shiftWin (tag . workspace $ t) w s
 
@@ -181,17 +180,16 @@ tagPrompt c f = do
   mkXPrompt TagPrompt c (mkComplFunFromList' c sc) f
 
 tagComplList :: X [String]
-tagComplList = gets (concat . map (integrate' . stack) . workspaces . windowset) >>=
-    mapM getTags >>=
-    return . nub . concat
+tagComplList = gets (concatMap (integrate' . stack) . workspaces . windowset)
+           >>= mapM getTags
+           <&> nub . concat
 
 
 tagDelPrompt :: XPConfig -> X ()
 tagDelPrompt c = do
   sc <- tagDelComplList
-  if (sc /= [])
-    then mkXPrompt TagPrompt c (mkComplFunFromList' c sc) (\s -> withFocused (delTag s))
-    else return ()
+  when (sc /= []) $
+    mkXPrompt TagPrompt c (mkComplFunFromList' c sc) (withFocused . delTag)
 
 tagDelComplList :: X [String]
 tagDelComplList = gets windowset >>= maybe (return []) getTags . peek

XMonad/Actions/TreeSelect.hs

@@ -2,6 +2,7 @@
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE MultiWayIf #-}
+{-# LANGUAGE LambdaCase #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Actions.TreeSelect
@@ -65,7 +66,7 @@ module XMonad.Actions.TreeSelect
 import Control.Monad.Reader
 import Control.Monad.State
 import Data.Tree
-import Foreign
+import Foreign (shiftL, shiftR, (.&.))
 import System.IO
 import System.Posix.Process (forkProcess, executeFile)
 import XMonad hiding (liftX)
@@ -451,8 +452,8 @@ splitPath i = case break (== '.') i of
 -- >        ]
 -- >    ]
 treeselectAction :: TSConfig (X a) -> Forest (TSNode (X a)) -> X ()
-treeselectAction c xs = treeselect c xs >>= \x -> case x of
-    Just a  -> a >> return ()
+treeselectAction c xs = treeselect c xs >>= \case
+    Just a  -> void a
     Nothing -> return ()
 
 forMForest :: (Functor m, Applicative m, Monad m) => [Tree a] -> (a -> m b) -> m [Tree b]
@@ -464,7 +465,7 @@ mapMTree f (Node x xs) = Node <$> f x <*>  mapM (mapMTree f) xs
 
 -- | Quit returning the currently selected node
 select :: TreeSelect a (Maybe a)
-select = Just <$> gets (tsn_value . cursor . tss_tree)
+select = gets (Just . (tsn_value . cursor . tss_tree))
 
 -- | Quit without returning anything
 cancel :: TreeSelect a (Maybe a)

XMonad/Actions/UpdateFocus.hs

@@ -39,7 +39,7 @@ import qualified XMonad.StackSet as W
 
 -- | Changes the focus if the mouse is moved within an unfocused window.
 focusOnMouseMove :: Event -> X All
-focusOnMouseMove (MotionEvent { ev_x = x, ev_y = y, ev_window = root }) = do
+focusOnMouseMove MotionEvent{ ev_x = x, ev_y = y, ev_window = root } = do
     -- check only every 15 px to avoid excessive calls to translateCoordinates
     when (x `mod` 15 == 0 || y `mod` 15 == 0) $ do
       dpy <- asks display

XMonad/Actions/UpdatePointer.hs

@@ -104,5 +104,7 @@ lerp :: (RealFrac r, Real a, Real b) => r -> a -> b -> r
 lerp r a b = (1 - r) * realToFrac a + r * realToFrac b
 
 clip :: Ord a => (a, a) -> a -> a
-clip (lower, upper) x = if x < lower then lower
-    else if x > upper then upper else x
+clip (lower, upper) x
+  | x < lower = lower
+  | x > upper = upper
+  | otherwise = x

XMonad/Actions/Warp.hs

@@ -101,7 +101,7 @@ warpToWindow h v =
 warpToScreen :: ScreenId -> Rational -> Rational -> X ()
 warpToScreen n h v = do
     root <- asks theRoot
-    (StackSet {current = x, visible = xs}) <- gets windowset
+    StackSet{current = x, visible = xs} <- gets windowset
     whenJust (fmap (screenRect . W.screenDetail) . find ((n==) . W.screen) $ x : xs)
         $ \r ->
             warp root (rect_x r + fraction h (rect_width  r))

XMonad/Actions/WindowBringer.hs

@@ -146,7 +146,7 @@ windowMap' titler = do
   ws <- gets X.windowset
   M.fromList . concat <$> mapM keyValuePairs (W.workspaces ws)
  where keyValuePairs ws = mapM (keyValuePair ws) $ W.integrate' (W.stack ws)
-       keyValuePair ws w = flip (,) w <$> titler ws w
+       keyValuePair ws w = (, w) <$> titler ws w
 
 -- | Returns the window name as will be listed in dmenu.
 --   Tagged with the workspace ID, to guarantee uniqueness, and to let the user

XMonad/Actions/WindowMenu.hs

@@ -68,7 +68,7 @@ windowMenu = withFocused $ \w -> do
                     | tag <- tags ]
     runSelectedAction gsConfig actions
 
-getSize :: Window -> X (Rectangle)
+getSize :: Window -> X Rectangle
 getSize w = do
   d  <- asks display
   wa <- io $ getWindowAttributes d w

XMonad/Actions/WindowNavigation.hs

@@ -40,7 +40,7 @@ module XMonad.Actions.WindowNavigation (
                                        ) where
 
 import XMonad
-import XMonad.Prelude (catMaybes, fromMaybe, listToMaybe, sortBy)
+import XMonad.Prelude (catMaybes, fromMaybe, listToMaybe, sortOn)
 import XMonad.Util.Types (Direction2D(..))
 import qualified XMonad.StackSet as W
 
@@ -48,7 +48,6 @@ import Control.Arrow (second)
 import Data.IORef
 import Data.Map (Map())
 import qualified Data.Map as M
-import Data.Ord (comparing)
 import qualified Data.Set as S
 
 -- $usage
@@ -123,9 +122,12 @@ swap = withTargetWindow swapWithFocused
                                    mapWindows (swapWin currentWin targetWin) winSet
                 Nothing -> winSet
         mapWindows f ss = W.mapWorkspace (mapWindows' f) ss
-        mapWindows' f ws@(W.Workspace { W.stack = s }) = ws { W.stack = mapWindows'' f <$> s }
+        mapWindows' f ws@W.Workspace{ W.stack = s } = ws { W.stack = mapWindows'' f <$> s }
         mapWindows'' f (W.Stack focused up down) = W.Stack (f focused) (map f up) (map f down)
-        swapWin win1 win2 win = if win == win1 then win2 else if win == win2 then win1 else win
+        swapWin win1 win2 win
+          | win == win1 = win2
+          | win == win2 = win1
+          | otherwise = win
 
 withTargetWindow :: (Window -> WindowSet -> WindowSet) -> IORef WNState -> Direction2D -> X ()
 withTargetWindow adj posRef dir = fromCurrentPoint posRef $ \win pos -> do
@@ -191,7 +193,7 @@ windowRects = fmap catMaybes . mapM windowRect . S.toList =<< gets mapped
 windowRect :: Window -> X (Maybe (Window, Rectangle))
 windowRect win = withDisplay $ \dpy -> do
     (_, x, y, w, h, bw, _) <- io $ getGeometry dpy win
-    return $ Just $ (win, Rectangle x y (w + 2 * bw) (h + 2 * bw))
+    return $ Just (win, Rectangle x y (w + 2 * bw) (h + 2 * bw))
     `catchX` return Nothing
 
 -- Modified from droundy's implementation of WindowNavigation:
@@ -207,7 +209,7 @@ inr L (Point px py) (Rectangle rx ry w h) =             px > rx + fromIntegral w
                                             py >= ry && py < ry + fromIntegral h
 
 sortby :: Direction2D -> [(a,Rectangle)] -> [(a,Rectangle)]
-sortby D = sortBy $ comparing (rect_y . snd)
-sortby R = sortBy $ comparing (rect_x . snd)
+sortby D = sortOn (rect_y . snd)
+sortby R = sortOn (rect_x . snd)
 sortby U = reverse . sortby D
 sortby L = reverse . sortby R

XMonad/Actions/Workscreen.hs

@@ -67,14 +67,14 @@ instance ExtensionClass WorkscreenStorage where
 
 -- | Helper to group workspaces. Multiply workspace by screens number.
 expandWorkspace :: Int -> [WorkspaceId] -> [WorkspaceId]
-expandWorkspace nscr ws = concat $ map expandId ws
+expandWorkspace nscr = concatMap expandId
   where expandId wsId = let t = wsId ++ "_"
                         in map ((++) t . show ) [1..nscr]
 
 -- | Create workscreen list from workspace list. Group workspaces to
 -- packets of screens number size.
 fromWorkspace :: Int -> [WorkspaceId] -> [Workscreen]
-fromWorkspace n ws = map (\(a,b) -> Workscreen a b) $ zip [0..] (fromWorkspace' n ws)
+fromWorkspace n ws = zipWith Workscreen [0..] (fromWorkspace' n ws)
 fromWorkspace' :: Int -> [WorkspaceId] -> [[WorkspaceId]]
 fromWorkspace' _ [] = []
 fromWorkspace' n ws = take n ws : fromWorkspace' n (drop n ws)

XMonad/Actions/WorkspaceCursors.hs

@@ -49,10 +49,7 @@ import XMonad.Layout.LayoutModifier(ModifiedLayout(..),
 import XMonad(Typeable, Message, WorkspaceId, X, XState(windowset),
               fromMessage, sendMessage, windows, gets)
 import XMonad.Util.Stack (reverseS)
-import Control.Applicative (liftA2)
-import Control.Monad((<=<), guard, when)
-import Data.Foldable(toList)
-import Data.Maybe(fromJust, listToMaybe)
+import XMonad.Prelude (find, fromJust, guard, liftA2, toList, when, (<=<))
 
 -- $usage
 --
@@ -143,7 +140,7 @@ getFocus (End x) = x
 
 -- This could be made more efficient, if the fact that the suffixes are grouped
 focusTo ::  (Eq t) => t -> Cursors t -> Maybe (Cursors t)
-focusTo x = listToMaybe . filter ((x==) . getFocus) . changeFocus (const True)
+focusTo x = find ((x==) . getFocus) . changeFocus (const True)
 
 -- | non-wrapping version of 'W.focusUp''
 noWrapUp ::  W.Stack t -> W.Stack t
@@ -192,7 +189,7 @@ modifyLayer' f depth = modifyCursors (descend f depth)
 modifyCursors ::  (Cursors String -> X (Cursors String)) -> X ()
 modifyCursors = sendMessage . ChangeCursors . (liftA2 (>>) updateXMD return <=<)
 
-data WorkspaceCursors a = WorkspaceCursors (Cursors String)
+newtype WorkspaceCursors a = WorkspaceCursors (Cursors String)
     deriving (Typeable,Read,Show)
 
 -- | The state is stored in the 'WorkspaceCursors' layout modifier. Put this as
@@ -201,7 +198,7 @@ data WorkspaceCursors a = WorkspaceCursors (Cursors String)
 workspaceCursors :: Cursors String -> l a -> ModifiedLayout WorkspaceCursors l a
 workspaceCursors = ModifiedLayout . WorkspaceCursors
 
-data ChangeCursors = ChangeCursors { unWrap :: Cursors String -> X (Cursors String) }
+newtype ChangeCursors = ChangeCursors { unWrap :: Cursors String -> X (Cursors String) }
     deriving (Typeable)
 
 instance Message ChangeCursors

XMonad/Actions/WorkspaceNames.hs

@@ -161,7 +161,7 @@ swapNames w1 w2 = do
     WorkspaceNames m <- XS.get
     let getname w = fromMaybe "" $ M.lookup w m
         set w name m' = if null name then M.delete w m' else M.insert w name m'
-    XS.put $ WorkspaceNames $ set w1 (getname w2) $ set w2 (getname w1) $ m
+    XS.put $ WorkspaceNames $ set w1 (getname w2) $ set w2 (getname w1) m
 
 -- | Same behavior than 'XMonad.Prompt.Workspace.workspacePrompt' excepted it acts on the workspace name provided by this module.
 workspaceNamePrompt :: XPConfig -> (WorkspaceId -> X ()) -> X ()

XMonad/Config/Azerty.hs

@@ -46,7 +46,7 @@ azertyKeys = azertyKeysTop [0x26,0xe9,0x22,0x27,0x28,0x2d,0xe8,0x5f,0xe7,0xe0]
 
 belgianKeys = azertyKeysTop [0x26,0xe9,0x22,0x27,0x28,0xa7,0xe8,0x21,0xe7,0xe0]
 
-azertyKeysTop topRow conf@(XConfig {modMask = modm}) = M.fromList $
+azertyKeysTop topRow conf@XConfig{modMask = modm} = M.fromList $
     [((modm, xK_semicolon), sendMessage (IncMasterN (-1)))]
     ++
     [((m .|. modm, k), windows $ f i)

XMonad/Config/Bepo.hs

@@ -39,9 +39,8 @@ import qualified Data.Map as M
 
 bepoConfig = def { keys = bepoKeys <+> keys def }
 
-bepoKeys conf@(XConfig { modMask = modm }) = M.fromList $
-    [((modm, xK_semicolon), sendMessage (IncMasterN (-1)))]
-    ++
-    [((m .|. modm, k), windows $ f i)
+bepoKeys conf@XConfig { modMask = modm } = M.fromList $
+    ((modm, xK_semicolon), sendMessage (IncMasterN (-1)))
+    : [((m .|. modm, k), windows $ f i)
           | (i, k) <- zip (workspaces conf) [0x22,0xab,0xbb,0x28,0x29,0x40,0x2b,0x2d,0x2f,0x2a],
             (f, m) <- [(W.greedyView, 0), (W.shift, shiftMask)]]

XMonad/Config/Bluetile.hs

@@ -80,7 +80,7 @@ bluetileWorkspaces :: [String]
 bluetileWorkspaces = ["1","2","3","4","5","6","7","8","9","0"]
 
 bluetileKeys :: XConfig Layout -> M.Map (KeyMask, KeySym) (X ())
-bluetileKeys conf@(XConfig {XMonad.modMask = modMask'}) = M.fromList $
+bluetileKeys conf@XConfig{XMonad.modMask = modMask'} = M.fromList $
     -- launching and killing programs
     [ ((modMask'              , xK_Return), spawn $ XMonad.terminal conf) -- %! Launch terminal
     , ((modMask',               xK_p     ), gnomeRun)    --  %! Launch Gnome "Run application" dialog
@@ -111,14 +111,14 @@ bluetileKeys conf@(XConfig {XMonad.modMask = modMask'}) = M.fromList $
 
     -- floating layer support
     , ((modMask',               xK_t     ), withFocused $ windows . W.sink) -- %! Push window back into tiling
-    , ((modMask' .|. shiftMask, xK_t     ), withFocused $ float ) -- %! Float window
+    , ((modMask' .|. shiftMask, xK_t     ), withFocused float ) -- %! Float window
 
     -- increase or decrease number of windows in the master area
     , ((modMask'              , xK_comma ), sendMessage (IncMasterN 1)) -- %! Increment the number of windows in the master area
     , ((modMask'              , xK_period), sendMessage (IncMasterN (-1))) -- %! Deincrement the number of windows in the master area
 
     -- quit, or restart
-    , ((modMask' .|. shiftMask, xK_q     ), io (exitWith ExitSuccess)) -- %! Quit
+    , ((modMask' .|. shiftMask, xK_q     ), io exitSuccess) -- %! Quit
     , ((modMask'              , xK_q     ), restart "xmonad" True) -- %! Restart
 
     -- Metacity-like workspace switching
@@ -158,19 +158,19 @@ bluetileKeys conf@(XConfig {XMonad.modMask = modMask'}) = M.fromList $
         , (f, m) <- [(W.view, 0), (W.shift, shiftMask)]]
 
 bluetileMouseBindings :: XConfig Layout -> M.Map (KeyMask, Button) (Window -> X ())
-bluetileMouseBindings (XConfig {XMonad.modMask = modMask'}) = M.fromList $
+bluetileMouseBindings XConfig{XMonad.modMask = modMask'} = M.fromList
     -- mod-button1 %! Move a floated window by dragging
-    [ ((modMask', button1), (\w -> isFloating w >>= \isF -> when (isF) $
-                                focus w >> mouseMoveWindow w >> windows W.shiftMaster))
+    [ ((modMask', button1), \w -> isFloating w >>= \isF -> when isF $
+                                focus w >> mouseMoveWindow w >> windows W.shiftMaster)
     -- mod-button2 %! Switch to next and first layout
-    , ((modMask', button2), (\_ -> sendMessage NextLayout))
-    , ((modMask' .|. shiftMask, button2), (\_ -> sendMessage $ JumpToLayout "Floating"))
+    , ((modMask', button2), \_ -> sendMessage NextLayout)
+    , ((modMask' .|. shiftMask, button2), \_ -> sendMessage $ JumpToLayout "Floating")
     -- mod-button3 %! Resize a floated window by dragging
-    , ((modMask', button3), (\w -> isFloating w >>= \isF -> when (isF) $
-                                focus w >> mouseResizeWindow w >> windows W.shiftMaster))
+    , ((modMask', button3), \w -> isFloating w >>= \isF -> when isF $
+                                focus w >> mouseResizeWindow w >> windows W.shiftMaster)
     ]
 
-isFloating :: Window -> X (Bool)
+isFloating :: Window -> X Bool
 isFloating w = do
     ws <- gets windowset
     return $ M.member w (W.floating ws)
@@ -181,16 +181,15 @@ bluetileManageHook = composeAll
                 , className =? "MPlayer" --> doFloat
                 , isFullscreen --> doFullFloat]
 
-bluetileLayoutHook = avoidStruts $ minimize $ boringWindows $ (
+bluetileLayoutHook = avoidStruts $ minimize $ boringWindows $
                         named "Floating" floating |||
                         named "Tiled1" tiled1 |||
                         named "Tiled2" tiled2 |||
                         named "Fullscreen" fullscreen
-                        )
         where
-            floating = floatingDeco $ maximize $ borderResize $ positionStoreFloat
-            tiled1 = tilingDeco $ maximize $ mouseResizableTileMirrored
-            tiled2 = tilingDeco $ maximize $ mouseResizableTile
+            floating = floatingDeco $ maximize $ borderResize positionStoreFloat
+            tiled1 = tilingDeco $ maximize mouseResizableTileMirrored
+            tiled2 = tilingDeco $ maximize mouseResizableTile
             fullscreen = tilingDeco $ maximize $ smartBorders Full
 
             tilingDeco l = windowSwitcherDecorationWithButtons shrinkText defaultThemeWithButtons (draggingVisualizer l)

XMonad/Config/Desktop.hs

@@ -171,10 +171,10 @@ desktopConfig = docks $ ewmh def
     , logHook         = desktopLogHook <+> logHook def
     , keys            = desktopKeys <+> keys def }
 
-desktopKeys (XConfig {modMask = modm}) = M.fromList $
+desktopKeys XConfig{modMask = modm} = M.fromList
     [ ((modm, xK_b), sendMessage ToggleStruts) ]
 
-desktopLayoutModifiers layout = avoidStruts layout
+desktopLayoutModifiers = avoidStruts
 
 -- | 'logHook' preserving old 'ewmh' behavior to switch workspace and focus to
 -- activated window.

XMonad/Config/Dmwit.hs

@@ -232,7 +232,7 @@ keyBindings conf = let m = modMask conf in fromList . anyMask $ [
     ((m .|. shiftMask  , xK_p          ), spawnHere termLauncher),
     ((m .|. shiftMask  , xK_c          ), kill),
     ((m                , xK_q          ), restart "xmonad" True),
-    ((m .|. shiftMask  , xK_q          ), io (exitWith ExitSuccess)),
+    ((m .|. shiftMask  , xK_q          ), io exitSuccess),
     ((m                , xK_grave      ), sendMessage NextLayout),
     ((m .|. shiftMask  , xK_grave      ), setLayout $ layoutHook conf),
     ((m                , xK_o          ), sendMessage Toggle),

XMonad/Config/Droundy.hs

@@ -14,7 +14,7 @@ import qualified XMonad (keys)
 
 import qualified XMonad.StackSet as W
 import qualified Data.Map as M
-import System.Exit ( exitWith, ExitCode(ExitSuccess) )
+import System.Exit ( exitSuccess )
 
 import XMonad.Layout.Tabbed ( tabbed,
                               shrinkText, Shrinker, shrinkIt, CustomShrink(CustomShrink) )
@@ -77,7 +77,7 @@ keys x = M.fromList $
     , ((modMask x,               xK_t     ), withFocused $ windows . W.sink) -- %! Push window back into tiling
 
     -- quit, or restart
-    , ((modMask x .|. shiftMask, xK_Escape), io (exitWith ExitSuccess)) -- %! Quit xmonad
+    , ((modMask x .|. shiftMask, xK_Escape), io exitSuccess) -- %! Quit xmonad
     , ((modMask x              , xK_Escape), restart "xmonad" True) -- %! Restart xmonad
 
     , ((modMask x .|. shiftMask, xK_Right), moveTo Next HiddenNonEmptyWS)

XMonad/Config/Example.hs

@@ -29,7 +29,7 @@ main = do
   xmonad $ desktopConfig
     { modMask    = mod4Mask -- Use the "Win" key for the mod key
     , manageHook = myManageHook <+> manageHook desktopConfig
-    , layoutHook = desktopLayoutModifiers $ myLayouts
+    , layoutHook = desktopLayoutModifiers myLayouts
     , logHook    = (dynamicLogString def >>= xmonadPropLog)
                     <+> logHook desktopConfig
     }

XMonad/Config/Gnome.hs

@@ -45,7 +45,7 @@ gnomeConfig = desktopConfig
     , keys     = gnomeKeys <+> keys desktopConfig
     , startupHook = gnomeRegister >> startupHook desktopConfig }
 
-gnomeKeys (XConfig {modMask = modm}) = M.fromList $
+gnomeKeys XConfig{modMask = modm} = M.fromList
     [ ((modm, xK_p), gnomeRun)
     , ((modm .|. shiftMask, xK_q), spawn "gnome-session-quit --logout") ]
 

XMonad/Config/Kde.hs

@@ -47,12 +47,12 @@ kde4Config = desktopConfig
     { terminal = "konsole"
     , keys     = kde4Keys <+> keys desktopConfig }
 
-kdeKeys (XConfig {modMask = modm}) = M.fromList $
+kdeKeys XConfig{modMask = modm} = M.fromList
     [ ((modm,               xK_p), spawn "dcop kdesktop default popupExecuteCommand")
     , ((modm .|. shiftMask, xK_q), spawn "dcop kdesktop default logout")
     ]
 
-kde4Keys (XConfig {modMask = modm}) = M.fromList $
+kde4Keys XConfig{modMask = modm} = M.fromList
     [ ((modm,               xK_p), spawn "krunner")
     , ((modm .|. shiftMask, xK_q), spawn "dbus-send --print-reply --dest=org.kde.ksmserver /KSMServer org.kde.KSMServerInterface.logout int32:1 int32:0 int32:1")
     ]

XMonad/Config/LXQt.hs

@@ -39,7 +39,7 @@ lxqtConfig = desktopConfig
     { terminal = "qterminal"
     , keys     = lxqtKeys <+> keys desktopConfig }
 
-lxqtKeys (XConfig {modMask = modm}) = M.fromList $
+lxqtKeys XConfig{modMask = modm} = M.fromList
     [ ((modm,               xK_p), spawn "lxqt-runner")
     , ((modm .|. shiftMask, xK_q), spawn "lxqt-leave")
     ]

XMonad/Config/Mate.hs

@@ -52,7 +52,7 @@ mateConfig = desktopConfig
     , keys     = mateKeys <+> keys desktopConfig
     , startupHook = mateRegister >> startupHook desktopConfig }
 
-mateKeys (XConfig {modMask = modm}) = M.fromList $
+mateKeys XConfig{modMask = modm} = M.fromList
     [ ((modm, xK_p), mateRun)
     , ((modm, xK_d), unGrab >> matePanel "MAIN_MENU")
     , ((modm .|. shiftMask, xK_q), mateLogout) ]

XMonad/Config/Monad.hs

@@ -45,5 +45,5 @@ add r x = tell (mkW (r ^: mappend x))
 --
 example :: Config ()
 example = do
-    add layout $ LL [Layout $ Full] -- make this better
+    add layout $ LL [Layout Full] -- make this better
     set terminal "urxvt"

XMonad/Config/Prime.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleContexts, FlexibleInstances, FunctionalDependencies, KindSignatures, MultiParamTypeClasses, UndecidableInstances #-}
+{-# LANGUAGE FlexibleContexts, FlexibleInstances, FunctionalDependencies, KindSignatures, UndecidableInstances #-}
 
 -----------------------------------------------------------------------------
 -- |
@@ -478,7 +478,7 @@ wsActions = Summable wsActions_ (\x c -> c { wsActions_ = x }) (++)
 -- >     wsSetName 1 "mail"
 -- >     wsSetName 2 "web"
 wsSetName :: Int -> String -> Arr WorkspaceConfig WorkspaceConfig
-wsSetName index newName = wsNames =. (map maybeSet . zip [0..])
+wsSetName index newName = wsNames =. zipWith (curry maybeSet) [0..]
   where maybeSet (i, oldName) | i == (index - 1) = newName
                               | otherwise = oldName
 
@@ -497,8 +497,8 @@ withScreens :: Arr ScreenConfig ScreenConfig -> Prime l l
 withScreens sarr xconf = (P.>>=) (sarr def) $ \sconf -> sprime sconf xconf
   where sprime :: ScreenConfig -> Prime l l
         sprime sconf =
-          (keys =+ [(mod ++ key, action sid) | (sid, key) <- zip [0..] (sKeys_ sconf),
-                                               (mod, action) <- sActions_ sconf])
+          keys =+ [(mod ++ key, action sid) | (sid, key) <- zip [0..] (sKeys_ sconf),
+                                              (mod, action) <- sActions_ sconf]
 
 data ScreenConfig = ScreenConfig {
   sKeys_ :: [String],

XMonad/Config/Saegesser.hs

@@ -58,7 +58,7 @@ myStartupHook = do
   spawnOnOnce "emacs" "emacs"
   spawnNOnOnce 4 "xterms" "xterm"
 
-myLayoutHook = smartBorders $ avoidStruts $ standardLayouts
+myLayoutHook = smartBorders $ avoidStruts standardLayouts
   where standardLayouts = tiled ||| mosaic 2 [3,2]  ||| Mirror tiled ||| Full
         tiled = ResizableTall nmaster delta ratio []
         nmaster = 1
@@ -68,7 +68,7 @@ myLayoutHook = smartBorders $ avoidStruts $ standardLayouts
 myLogHook p =  do
   copies <- wsContainingCopies
   let check ws | ws == "NSP" = ""                               -- Hide the scratchpad workspace
-               | ws `elem` copies = xmobarColor "red" "black" $ ws  -- Workspaces with copied windows are red on black
+               | ws `elem` copies = xmobarColor "red" "black" ws  -- Workspaces with copied windows are red on black
                | otherwise = ws
   dynamicLogWithPP $ xmobarPP { ppHidden = check
                               , ppOutput = hPutStrLn p

XMonad/Config/Sjanssen.hs

@@ -24,10 +24,10 @@ sjanssenConfig =
     docks $ ewmh $ def
         { terminal = "exec urxvt"
         , workspaces = ["irc", "web"] ++ map show [3 .. 9 :: Int]
-        , mouseBindings = \(XConfig {modMask = modm}) -> M.fromList $
-                [ ((modm, button1), (\w -> focus w >> mouseMoveWindow w))
-                , ((modm, button2), (\w -> focus w >> windows W.swapMaster))
-                , ((modm.|. shiftMask, button1), (\w -> focus w >> mouseResizeWindow w)) ]
+        , mouseBindings = \XConfig {modMask = modm} -> M.fromList
+                [ ((modm, button1), \w -> focus w >> mouseMoveWindow w)
+                , ((modm, button2), \w -> focus w >> windows W.swapMaster)
+                , ((modm.|. shiftMask, button1), \w -> focus w >> mouseResizeWindow w) ]
         , keys = \c -> mykeys c `M.union` keys def c
         , logHook = dynamicLogString sjanssenPP >>= xmonadPropLog
         , layoutHook  = modifiers layouts
@@ -50,12 +50,12 @@ sjanssenConfig =
              , "trayer --transparent true --expand true --align right "
                ++ "--edge bottom --widthtype request" ]
 
-    mykeys (XConfig {modMask = modm}) = M.fromList $
+    mykeys XConfig{modMask = modm} = M.fromList
         [((modm,               xK_p     ), shellPromptHere myPromptConfig)
         ,((modm .|. shiftMask, xK_Return), spawnHere =<< asks (terminal . config))
         ,((modm .|. shiftMask, xK_c     ), kill1)
         ,((modm .|. shiftMask .|. controlMask, xK_c     ), kill)
-        ,((modm .|. shiftMask, xK_0     ), windows $ copyToAll)
+        ,((modm .|. shiftMask, xK_0     ), windows copyToAll)
         ,((modm,               xK_z     ), layoutScreens 2 $ TwoPane 0.5 0.5)
         ,((modm .|. shiftMask, xK_z     ), rescreen)
         , ((modm             , xK_b     ), sendMessage ToggleStruts)

XMonad/Config/Xfce.hs

@@ -39,7 +39,7 @@ xfceConfig = desktopConfig
     { terminal = "xfce4-terminal"
     , keys     = xfceKeys <+> keys desktopConfig }
 
-xfceKeys (XConfig {modMask = modm}) = M.fromList $
+xfceKeys XConfig{modMask = modm} = M.fromList
     [ ((modm,               xK_p), spawn "xfrun4")
     , ((modm .|. shiftMask, xK_p), spawn "xfce4-appfinder")
     , ((modm .|. shiftMask, xK_q), spawn "xfce4-session-logout")

XMonad/Hooks/CurrentWorkspaceOnTop.hs

@@ -25,7 +25,7 @@ module XMonad.Hooks.CurrentWorkspaceOnTop (
 import XMonad
 import qualified XMonad.StackSet as S
 import qualified XMonad.Util.ExtensibleState as XS
-import XMonad.Prelude(when)
+import XMonad.Prelude (unless, when)
 import qualified Data.Map as M
 
 -- $usage
@@ -40,7 +40,7 @@ import qualified Data.Map as M
 -- >  }
 --
 
-data CWOTState = CWOTS String deriving Typeable
+newtype CWOTState = CWOTS String deriving Typeable
 
 instance ExtensionClass CWOTState where
   initialValue = CWOTS ""
@@ -55,15 +55,15 @@ currentWorkspaceOnTop = withDisplay $ \d -> do
         let s = S.current ws
             wsp = S.workspace s
             viewrect = screenRect $ S.screenDetail s
-            tmpStack = (S.stack wsp) >>= S.filter (`M.notMember` S.floating ws)
+            tmpStack = S.stack wsp >>= S.filter (`M.notMember` S.floating ws)
         (rs, ml') <- runLayout wsp { S.stack = tmpStack } viewrect
         updateLayout curTag ml'
         let this = S.view curTag ws
-            fltWins = filter (flip M.member (S.floating ws)) $ S.index this
-            wins = fltWins ++ (map fst rs)  -- order: first all floating windows, then the order the layout returned
+            fltWins = filter (`M.member` S.floating ws) $ S.index this
+            wins = fltWins ++ map fst rs  -- order: first all floating windows, then the order the layout returned
         -- end of reimplementation
 
-        when (not . null $ wins) $ do
+        unless (null wins) $ do
             io $ raiseWindow d (head wins)  -- raise first window of current workspace to the very top,
             io $ restackWindows d wins      -- then use restackWindows to let all other windows from the workspace follow
         XS.put(CWOTS curTag)

XMonad/Hooks/DebugEvents.hs

@@ -51,7 +51,7 @@ debugEventsHook e =  debugEventsHook' e >> return (All True)
 -- | Dump an X11 event.  Can't be used directly as a 'handleEventHook'.
 debugEventsHook' :: Event -> X ()
 
-debugEventsHook' (ConfigureRequestEvent {ev_window       = w
+debugEventsHook' ConfigureRequestEvent{ev_window       = w
                                       ,ev_parent       = p
                                       ,ev_x            = x
                                       ,ev_y            = y
@@ -61,7 +61,7 @@ debugEventsHook' (ConfigureRequestEvent {ev_window       = w
                                       ,ev_above        = above
                                       ,ev_detail       = place
                                       ,ev_value_mask   = msk
-                                        }) = do
+                                      } = do
   windowEvent "ConfigureRequest" w
   windowEvent "  parent"         p
 --  mask <- quickFormat msk $ dumpBits wmCRMask
@@ -84,45 +84,45 @@ debugEventsHook' (ConfigureRequestEvent {ev_window       = w
                            ]
   say "  requested" s
 
-debugEventsHook' (ConfigureEvent        {ev_window = w
+debugEventsHook' ConfigureEvent        {ev_window = w
                                        ,ev_above  = above
-                                        }) = do
+                                       } = do
   windowEvent "Configure" w
   -- most of the content is covered by debugWindow
   when (above /= none) $ debugWindow above >>= say "  above"
 
-debugEventsHook' (MapRequestEvent       {ev_window     = w
+debugEventsHook' MapRequestEvent       {ev_window     = w
                                        ,ev_parent     = p
-                                        }) =
+                                       } =
   windowEvent "MapRequest" w >>
   windowEvent "  parent"   p
 
-debugEventsHook' e@(KeyEvent {ev_event_type = t})
+debugEventsHook' e@KeyEvent {ev_event_type = t}
     | t == keyPress =
   io (hPutStr stderr "KeyPress ") >>
   debugKeyEvents e >>
   return ()
 
-debugEventsHook' (ButtonEvent           {ev_window = w
+debugEventsHook' ButtonEvent           {ev_window = w
                                        ,ev_state  = s
                                        ,ev_button = b
-                                        }) = do
+                                       } = do
   windowEvent "Button" w
   nl <- gets numberlockMask
   let msk | s == 0    = ""
           | otherwise = "modifiers " ++ vmask nl s
   say "  button" $ show b ++ msk
 
-debugEventsHook' (DestroyWindowEvent    {ev_window = w
-                                        }) =
+debugEventsHook' DestroyWindowEvent    {ev_window = w
+                                        } =
   windowEvent "DestroyWindow" w
 
-debugEventsHook' (UnmapEvent            {ev_window = w
-                                        }) =
+debugEventsHook' UnmapEvent            {ev_window = w
+                                       } =
   windowEvent "Unmap" w
 
-debugEventsHook' (MapNotifyEvent        {ev_window = w
-                                        }) =
+debugEventsHook' MapNotifyEvent        {ev_window = w
+                                       } =
   windowEvent "MapNotify" w
 
 {- way too much output; suppressed.
@@ -133,26 +133,24 @@ debugEventsHook' (CrossingEvent         {ev_window    = w
   windowEvent "Crossing"    w >>
   windowEvent "  subwindow" s
 -}
-debugEventsHook' (CrossingEvent         {}) =
+debugEventsHook' CrossingEvent         {} =
   return ()
 
-debugEventsHook' (SelectionRequest      {ev_requestor = rw
+debugEventsHook' SelectionRequest      {ev_requestor = rw
                                        ,ev_owner     = ow
                                        ,ev_selection = a
-                                        }) =
+                                       } =
   windowEvent "SelectionRequest" rw >>
   windowEvent "  owner"          ow >>
   atomEvent   "  atom"           a
 
-debugEventsHook' (PropertyEvent         {ev_window    = w
+debugEventsHook' PropertyEvent         {ev_window    = w
                                        ,ev_atom      = a
                                        ,ev_propstate = s
-                                        }) = do
+                                       } = do
   a' <- atomName a
   -- too many of these, and they're not real useful
-  if a' `elem` ["_NET_WM_USER_TIME"
---               ,"_NET_WM_WINDOW_OPACITY"
-               ] then return () else do
+  if a' == "_NET_WM_USER_TIME" then return () else do
   windowEvent "Property on" w
   s' <- case s of
           1 -> return "deleted"
@@ -160,11 +158,11 @@ debugEventsHook' (PropertyEvent         {ev_window    = w
           _ -> error "Illegal propState; Xlib corrupted?"
   say "  atom" $ a' ++ s'
 
-debugEventsHook' (ExposeEvent           {ev_window = w
-                                        }) =
+debugEventsHook' ExposeEvent           {ev_window = w
+                                       } =
   windowEvent "Expose" w
 
-debugEventsHook' (ClientMessageEvent    {ev_window       = w
+debugEventsHook' ClientMessageEvent    {ev_window       = w
                                        ,ev_message_type = a
                                        -- @@@ they did it again!  no ev_format,
                                        --     and ev_data is [CInt]
@@ -172,7 +170,7 @@ debugEventsHook' (ClientMessageEvent    {ev_window       = w
                                        --     that is setClientMessageEvent!
 --                                     ,ev_format       = b
                                        ,ev_data         = vs'
-                                        }) = do
+                                       } = do
   windowEvent "ClientMessage on" w
   n <- atomName a
   -- this is a sort of custom property
@@ -219,12 +217,6 @@ clientMessages =  [("_NET_ACTIVE_WINDOW",("_NET_ACTIVE_WINDOW",32,1))
                   ,("WM_SAVE_YOURSELF"  ,("STRING"            , 8,0))
                   ]
 
-#if __GLASGOW_HASKELL__ < 707
-finiteBitSize :: Bits a => a -> Int
-finiteBitSize x = bitSize x
-#endif
-
-
 -- | Convert a modifier mask into a useful string
 vmask                 :: KeyMask -> KeyMask -> String
 vmask numLockMask msk =  unwords $
@@ -604,7 +596,7 @@ dumpArray item =  do
 dumpArray'          :: Decoder Bool -> String -> Decoder Bool
 dumpArray' item pfx =  do
   vs <- gets value
-  if vs == []
+  if null vs
     then append "]"
     else append pfx >> whenD item (dumpArray' item ",")
 
@@ -713,7 +705,7 @@ dumpString =  do
                                                 go []       _ = append "]"
                                              in append "[" >> go ss' ""
        | fmt == uTF8_STRING   -> dumpUTF -- duplicate type test instead of code :)
-       | otherwise            -> (inX $ atomName fmt) >>=
+       | otherwise            -> inX (atomName fmt) >>=
                                  failure . ("unrecognized string type " ++)
 
 -- show who owns a selection
@@ -744,7 +736,7 @@ dumpXKlInds =  guardType iNTEGER $ do
                        | n .&. bt /= 0    =  dumpInds (n .&. complement bt)
                                                       (bt `shiftL` 1)
                                                       (c + 1)
-                                                      ((show c):bs)
+                                                      (show c:bs)
                        | otherwise        =  dumpInds n
                                                       (bt `shiftL` 1)
                                                       (c + 1)
@@ -1189,7 +1181,7 @@ inhale  b =  error $ "inhale " ++ show b
 
 eat   :: Int -> Decoder Raw
 eat n =  do
-  (bs,rest) <- splitAt n <$> gets value
+  (bs,rest) <- gets (splitAt n . value)
   modify (\r -> r {value = rest})
   return bs
 

XMonad/Hooks/DebugKeyEvents.hs

@@ -56,13 +56,13 @@ import           System.IO                       (hPutStrLn
 
 -- | Print key events to stderr for debugging
 debugKeyEvents :: Event -> X All
-debugKeyEvents (KeyEvent {ev_event_type = t, ev_state = m, ev_keycode = code})
+debugKeyEvents KeyEvent{ev_event_type = t, ev_state = m, ev_keycode = code}
   | t == keyPress =
       withDisplay $ \dpy -> do
         sym <- io $ keycodeToKeysym dpy code 0
         msk <- cleanMask m
         nl <- gets numberlockMask
-        io $ hPutStrLn stderr $ intercalate " " ["keycode"
+        io $ hPutStrLn stderr $ unwords ["keycode"
                                         ,show code
                                         ,"sym"
                                         ,show sym
@@ -86,7 +86,7 @@ hex v = "0x" ++ showHex v ""
 
 -- | Convert a modifier mask into a useful string
 vmask                 :: KeyMask -> KeyMask -> String
-vmask numLockMask msk =  intercalate " " $
+vmask numLockMask msk =  unwords $
                          reverse $
                          fst $
                          foldr vmask' ([],msk) masks

XMonad/Hooks/DynamicBars.hs

@@ -79,7 +79,7 @@ import qualified XMonad.Util.ExtensibleState as XS
 -- is called when the number of screens changes and on startup.
 --
 
-data DynStatusBarInfo = DynStatusBarInfo
+newtype DynStatusBarInfo = DynStatusBarInfo
   { dsbInfo :: [(ScreenId, Handle)]
   } deriving (Typeable)
 
@@ -113,12 +113,12 @@ dynStatusBarEventHook' :: DynamicStatusBar -> DynamicStatusBarPartialCleanup ->
 dynStatusBarEventHook' sb cleanup = dynStatusBarRun (updateStatusBars' sb cleanup)
 
 dynStatusBarRun :: X () -> Event -> X All
-dynStatusBarRun action (RRScreenChangeNotifyEvent {}) = action >> return (All True)
+dynStatusBarRun action RRScreenChangeNotifyEvent{} = action >> return (All True)
 dynStatusBarRun _      _                           = return (All True)
 
 updateStatusBars :: DynamicStatusBar -> DynamicStatusBarCleanup -> X ()
 updateStatusBars sb cleanup = do
-  (dsbInfoScreens, dsbInfoHandles) <- XS.get >>= return . unzip . dsbInfo
+  (dsbInfoScreens, dsbInfoHandles) <- XS.get <&> unzip . dsbInfo
   screens <- getScreens
   when (screens /= dsbInfoScreens) $ do
       newHandles <- liftIO $ do
@@ -129,14 +129,14 @@ updateStatusBars sb cleanup = do
 
 updateStatusBars' :: DynamicStatusBar -> DynamicStatusBarPartialCleanup -> X ()
 updateStatusBars' sb cleanup = do
-  (dsbInfoScreens, dsbInfoHandles) <- XS.get >>= return . unzip . dsbInfo
+  (dsbInfoScreens, dsbInfoHandles) <- XS.get <&> (unzip . dsbInfo)
   screens <- getScreens
   when (screens /= dsbInfoScreens) $ do
       let oldInfo = zip dsbInfoScreens dsbInfoHandles
       let (infoToKeep, infoToClose) = partition (flip elem screens . fst) oldInfo
       newInfo <- liftIO $ do
-          mapM_ hClose $ map snd infoToClose
-          mapM_ cleanup $ map fst infoToClose
+          mapM_ (hClose . snd) infoToClose
+          mapM_ (cleanup . fst) infoToClose
           let newScreens = screens \\ dsbInfoScreens
           newHandles <- mapM sb newScreens
           return $ zip newScreens newHandles
@@ -153,7 +153,7 @@ multiPP = multiPPFormat dynamicLogString
 
 multiPPFormat :: (PP -> X String) -> PP -> PP -> X ()
 multiPPFormat dynlStr focusPP unfocusPP = do
-  (_, dsbInfoHandles) <- XS.get >>= return . unzip . dsbInfo
+  (_, dsbInfoHandles) <- XS.get <&> unzip . dsbInfo
   multiPP' dynlStr focusPP unfocusPP dsbInfoHandles
 
 multiPP' :: (PP -> X String) -> PP -> PP -> [Handle] -> X ()

XMonad/Hooks/DynamicHooks.hs

@@ -59,16 +59,16 @@ instance ExtensionClass DynamicHooks where
 -- doFloat and doIgnore are idempotent.
 -- | Master 'ManageHook' that must be in your @xmonad.hs@ 'ManageHook'.
 dynamicMasterHook :: ManageHook
-dynamicMasterHook = (ask >>= \w -> liftX (do
+dynamicMasterHook = ask >>= \w -> liftX $ do
   dh <- XS.get
   (Endo f)  <- runQuery (permanent dh) w
   ts <- mapM (\(q,a) -> runQuery q w >>= \x -> return (x,(q, a))) (transients dh)
   let (ts',nts) = partition fst ts
   gs <- mapM (flip runQuery w . snd . snd) ts'
-  let (Endo g) = maybe (Endo id) id $ listToMaybe gs
+  let (Endo g) = fromMaybe (Endo id) $ listToMaybe gs
   XS.put $ dh { transients = map snd nts }
   return $ Endo $ f . g
-                                       ))
+
 -- | Appends the given 'ManageHook' to the permanent dynamic 'ManageHook'.
 addDynamicHook :: ManageHook -> X ()
 addDynamicHook m = updateDynamicHook (<+> m)
@@ -87,4 +87,4 @@ updateDynamicHook f = XS.modify $ \dh -> dh { permanent = f (permanent dh) }
 -- > oneShotHook dynHooksRef (className =? "example) doFloat
 --
 oneShotHook :: Query Bool -> ManageHook -> X ()
-oneShotHook q a = XS.modify $ \dh -> dh { transients = (q,a):(transients dh) }
+oneShotHook q a = XS.modify $ \dh -> dh { transients = (q,a):transients dh }

XMonad/Hooks/DynamicIcons.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE RecordWildCards #-}
-{-# LANGUAGE TupleSections #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Hooks.DynamicIcons

XMonad/Hooks/EwmhDesktops.hs

@@ -178,7 +178,7 @@ ewmhDesktopsLogHookCustom t = withWindowSet $ \s -> do
 
     -- Remap the current workspace to handle any renames that f might be doing.
     let maybeCurrent' = W.tag <$> listToMaybe (t [W.workspace $ W.current s])
-        current = join (flip elemIndex (map W.tag ws) <$> maybeCurrent')
+        current = flip elemIndex (map W.tag ws) =<< maybeCurrent'
     whenChanged (CurrentDesktop $ fromMaybe 0 current) $
         mapM_ setCurrentDesktop current
 
@@ -392,7 +392,7 @@ addSupported props = withDisplay $ \dpy -> do
     a <- getAtom "_NET_SUPPORTED"
     newSupportedList <- mapM (fmap fromIntegral . getAtom) props
     io $ do
-        supportedList <- fmap (join . maybeToList) $ getWindowProperty32 dpy a r
+        supportedList <- join . maybeToList <$> getWindowProperty32 dpy a r
         changeProperty32 dpy r a aTOM propModeReplace (nub $ newSupportedList ++ supportedList)
 
 setFullscreenSupported :: X ()

XMonad/Hooks/FadeInactive.hs

@@ -91,7 +91,7 @@ fadeInactiveCurrentWSLogHook = fadeOutLogHook . fadeIf isUnfocusedOnCurrentWS
 
 -- | Returns True if the window doesn't have the focus.
 isUnfocused :: Query Bool
-isUnfocused = ask >>= \w -> liftX . gets $ maybe True (w /=) . W.peek . windowset
+isUnfocused = ask >>= \w -> liftX . gets $ (Just w /=) . W.peek . windowset
 
 -- | Returns True if the window doesn't have the focus, and the window is on the
 -- current workspace. This is specifically handy in a multi monitor setup
@@ -103,7 +103,7 @@ isUnfocusedOnCurrentWS = do
   w <- ask
   ws <- liftX $ gets windowset
   let thisWS = w `elem` W.index ws
-      unfocused = maybe True (w /=) $ W.peek ws
+      unfocused = Just w /= W.peek ws
   return $ thisWS && unfocused
 
 -- | Fades out every window by the amount returned by the query.

XMonad/Hooks/FadeWindows.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Hooks.FadeWindows
@@ -220,7 +220,7 @@ fadeWindowsLogHook h =  withWindowSet $ \s -> do
 --   "XMonad.Layout.Full" or "XMonad.Layout.Tabbed".  This hook may
 --   also be useful with "XMonad.Hooks.FadeInactive".
 fadeWindowsEventHook                     :: Event -> X All
-fadeWindowsEventHook (MapNotifyEvent {}) =
+fadeWindowsEventHook MapNotifyEvent{} =
   -- we need to run the fadeWindowsLogHook.  only one way...
   asks config >>= logHook >> return (All True)
 fadeWindowsEventHook _                   =  return (All True)

XMonad/Hooks/FloatNext.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE DeriveDataTypeable #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Hooks.FloatNext

XMonad/Hooks/Focus.hs

@@ -441,7 +441,7 @@ focusedCur' m       = asks currentWorkspace >>= \i -> focusedOn' i m
 
 -- | Does new window appear at particular workspace?
 newOn :: WorkspaceId -> FocusQuery Bool
-newOn i             = (i ==) <$> asks newWorkspace
+newOn i             = asks ((i ==) . newWorkspace)
 -- | Does new window appear at current workspace?
 newOnCur :: FocusQuery Bool
 newOnCur            = asks currentWorkspace >>= newOn

XMonad/Hooks/ICCCMFocus.hs

@@ -38,5 +38,5 @@ takeFocusX _w = return ()
 takeTopFocus ::
   X ()
 takeTopFocus =
-  (withWindowSet $ maybe (setFocusX =<< asks theRoot) takeFocusX . W.peek) >> setWMName "LG3D"
+  withWindowSet (maybe (setFocusX =<< asks theRoot) takeFocusX . W.peek) >> setWMName "LG3D"
 

XMonad/Hooks/InsertPosition.hs

@@ -21,7 +21,7 @@ module XMonad.Hooks.InsertPosition (
     ) where
 
 import XMonad(ManageHook, MonadReader(ask))
-import XMonad.Prelude (Endo (Endo), find, fromMaybe)
+import XMonad.Prelude (Endo (Endo), find)
 import qualified XMonad.StackSet as W
 
 -- $usage
@@ -44,7 +44,7 @@ insertPosition :: Position -> Focus -> ManageHook
 insertPosition pos foc = Endo . g <$> ask
   where
     g w = viewingWs w (updateFocus w . ins w . W.delete' w)
-    ins w = (\f ws -> fromMaybe id (W.focusWindow <$> W.peek ws) $ f ws) $
+    ins w = (\f ws -> maybe id W.focusWindow (W.peek ws) $ f ws) $
         case pos of
             Master -> W.insertUp w . W.focusMaster
             End    -> insertDown w . W.modify' focusLast'

XMonad/Hooks/ManageDebug.hs

@@ -36,7 +36,7 @@ import           XMonad.Util.EZConfig
 import qualified XMonad.Util.ExtensibleState                                                 as XS
 
 -- persistent state for manageHook debugging to trigger logHook debugging
-data ManageStackDebug = MSD (Bool,Bool) deriving Typeable
+newtype ManageStackDebug = MSD (Bool,Bool) deriving Typeable
 instance ExtensionClass ManageStackDebug where
   initialValue = MSD (False,False)
 

XMonad/Hooks/ManageDocks.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE DeriveDataTypeable, PatternGuards, FlexibleInstances, MultiParamTypeClasses, CPP #-}
-{-# LANGUAGE LambdaCase #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module       : XMonad.Hooks.ManageDocks
@@ -152,30 +151,30 @@ checkDock = ask >>= \w -> liftX $ do
     desk <- getAtom "_NET_WM_WINDOW_TYPE_DESKTOP"
     mbr <- getProp32s "_NET_WM_WINDOW_TYPE" w
     case mbr of
-        Just rs -> return $ any (`elem` [dock,desk]) (map fromIntegral rs)
+        Just rs -> return $ any ((`elem` [dock,desk]) . fromIntegral) rs
         _       -> return False
 
 -- | Whenever a new dock appears, refresh the layout immediately to avoid the
 -- new dock.
 docksEventHook :: Event -> X All
-docksEventHook (MapNotifyEvent { ev_window = w }) = do
+docksEventHook MapNotifyEvent{ ev_window = w } = do
     whenX (runQuery checkDock w <&&> (not <$> isClient w)) $
         whenX (updateStrutCache w) refreshDocks
     return (All True)
-docksEventHook (PropertyEvent { ev_window = w
-                              , ev_atom = a }) = do
+docksEventHook PropertyEvent{ ev_window = w
+                            , ev_atom = a } = do
     nws <- getAtom "_NET_WM_STRUT"
     nwsp <- getAtom "_NET_WM_STRUT_PARTIAL"
     when (a == nws || a == nwsp) $
         whenX (updateStrutCache w) refreshDocks
     return (All True)
-docksEventHook (DestroyWindowEvent {ev_window = w}) = do
+docksEventHook DestroyWindowEvent{ ev_window = w } = do
     whenX (deleteFromStrutCache w) refreshDocks
     return (All True)
 docksEventHook _ = return (All True)
 
 docksStartupHook :: X ()
-docksStartupHook = void $ getStrutCache
+docksStartupHook = void getStrutCache
 
 -- | Gets the STRUT config, if present, in xmonad gap order
 getStrut :: Window -> X [Strut]
@@ -222,7 +221,7 @@ avoidStrutsOn :: LayoutClass l a =>
               -> ModifiedLayout AvoidStruts l a
 avoidStrutsOn ss = ModifiedLayout $ AvoidStruts (S.fromList ss)
 
-data AvoidStruts a = AvoidStruts (S.Set Direction2D) deriving ( Read, Show )
+newtype AvoidStruts a = AvoidStruts (S.Set Direction2D) deriving ( Read, Show )
 
 -- | Message type which can be sent to an 'AvoidStruts' layout
 --   modifier to alter its behavior.

XMonad/Hooks/ManageHelpers.hs

@@ -85,9 +85,7 @@ composeOne = foldr try (return mempty)
     where
     try q z = do
         x <- q
-        case x of
-            Just h -> return h
-            Nothing -> z
+        maybe z return x
 
 infixr 0 -?>, -->>, -?>>
 
@@ -119,7 +117,7 @@ p -?> f = do
 (-->>) :: (Monoid b, Monad m) => m (Match a) -> (a -> m b) -> m b
 p -->> f = do
     Match b m <- p
-    if b then (f m) else return mempty
+    if b then f m else return mempty
 
 -- | A helper operator for use in 'composeOne'.  It takes a condition and a function taking a groupdatum to action.  If 'p' is true, it executes the resulting action.  If it fails, it returns 'Nothing' from the 'Query' so 'composeOne' will go on and try the next rule.
 (-?>>) :: (Functor m, Monad m) => m (Match a) -> (a -> m b) -> m (Maybe b)
@@ -166,7 +164,7 @@ isDialog = isInProperty "_NET_WM_WINDOW_TYPE" "_NET_WM_WINDOW_TYPE_DIALOG"
 --
 -- See <https://specifications.freedesktop.org/wm-spec/wm-spec-1.5.html#idm45623487788432>.
 pid :: Query (Maybe ProcessID)
-pid = ask >>= \w -> liftX $ getProp32s "_NET_WM_PID" w >>= pure . \case
+pid = ask >>= \w -> liftX $ getProp32s "_NET_WM_PID" w <&> \case
     Just [x] -> Just (fromIntegral x)
     _        -> Nothing
 
@@ -196,7 +194,7 @@ transience' = maybeToDefinite transience
 --
 -- See <https://tronche.com/gui/x/icccm/sec-5.html>.
 clientLeader :: Query (Maybe Window)
-clientLeader = ask >>= \w -> liftX $ getProp32s "WM_CLIENT_LEADER" w >>= pure . \case
+clientLeader = ask >>= \w -> liftX $ getProp32s "WM_CLIENT_LEADER" w <&> \case
     Just [x] -> Just (fromIntegral x)
     _        -> Nothing
 
@@ -256,12 +254,14 @@ doSideFloat :: Side -> ManageHook
 doSideFloat side = doFloatDep move
   where
     move (W.RationalRect _ _ w h) = W.RationalRect cx cy w h
-      where cx =      if side `elem` [SC,C ,NC] then (1-w)/2
-                 else if side `elem` [SW,CW,NW] then 0
-                 else {- side `elem` [SE,CE,NE] -}   1-w
-            cy =      if side `elem` [CE,C ,CW] then (1-h)/2
-                 else if side `elem` [NE,NC,NW] then 0
-                 else {- side `elem` [SE,SC,SW] -}   1-h
+      where cx
+              | side `elem` [SC,C ,NC] = (1-w)/2
+              | side `elem` [SW,CW,NW] = 0
+              | otherwise = {- side `elem` [SE,CE,NE] -} 1-w
+            cy
+              | side `elem` [CE,C ,CW] = (1-h)/2
+              | side `elem` [NE,NC,NW] = 0
+              | otherwise = {- side `elem` [SE,SC,SW] -} 1-h
 
 -- | Floats a new window with its original size, but centered.
 doCenterFloat :: ManageHook

XMonad/Hooks/Minimize.hs

@@ -35,9 +35,9 @@ import XMonad.Prelude
 -- >                   , handleEventHook = myHandleEventHook }
 
 minimizeEventHook :: Event -> X All
-minimizeEventHook (ClientMessageEvent {ev_window = w,
+minimizeEventHook ClientMessageEvent{ev_window = w,
                                      ev_message_type = mt,
-                                       ev_data = dt}) = do
+                                     ev_data = dt} = do
     a_aw <- getAtom "_NET_ACTIVE_WINDOW"
     a_cs <- getAtom "WM_CHANGE_STATE"
 

XMonad/Hooks/Place.hs

@@ -162,16 +162,16 @@ placeFocused p = withFocused $ \window -> do
 
                      -- use X.A.FloatKeys if the window is floating, send
                      -- a WindowArranger message otherwise.
-                   case elem window floats of
-                     True -> keysMoveWindowTo (x', y') (0, 0) window
-                     False -> sendMessage $ SetGeometry r'
+                   if window `elem` floats
+                     then keysMoveWindowTo (x', y') (0, 0) window
+                     else sendMessage $ SetGeometry r'
 
 
 -- | Hook to automatically place windows when they are created.
 placeHook :: Placement -> ManageHook
 placeHook p = do window <- ask
                  r <- Query $ lift $ getWindowRectangle window
-                 allRs <- Query $ lift $ getAllRectangles
+                 allRs <- Query $ lift getAllRectangles
                  pointer <- Query $ lift $ getPointer window
 
                  return $ Endo $ \theWS -> fromMaybe theWS $
@@ -186,13 +186,13 @@ placeHook p = do window <- ask
                         -- workspace's screen.
                       let infos = filter ((window `elem`) . stackContents . S.stack . fst)
                                      $ [screenInfo $ S.current theWS]
-                                        ++ (map screenInfo $ S.visible theWS)
+                                        ++ map screenInfo (S.visible theWS)
                                         ++ zip (S.hidden theWS) (repeat currentRect)
 
                       guard(not $ null infos)
 
                       let (workspace, screen) = head infos
-                          rs = catMaybes $ map (flip M.lookup allRs)
+                          rs = mapMaybe (`M.lookup` allRs)
                                $ organizeClients workspace window floats
                           r' = purePlaceWindow p screen rs pointer r
                           newRect = r2rr screen r'
@@ -221,7 +221,7 @@ purePlaceWindow :: Placement -- ^ The placement strategy
                 -> Rectangle -- ^ The window to be placed
                 -> Rectangle
 purePlaceWindow (Bounds (t,r,b,l) p') (Rectangle sx sy sw sh) rs p w
-  = let s' = (Rectangle (sx + fi l) (sy + fi t) (sw - l - r) (sh - t - b))
+  = let s' = Rectangle (sx + fi l) (sy + fi t) (sw - l - r) (sh - t - b)
     in checkBounds s' $ purePlaceWindow p' s' rs p w
 
 purePlaceWindow (Fixed ratios) s _ _ w = placeRatio ratios s w
@@ -275,7 +275,7 @@ stackContents :: Maybe (S.Stack w) -> [w]
 stackContents = maybe [] S.integrate
 
 screenInfo :: S.Screen i l a sid ScreenDetail -> (S.Workspace i l a, Rectangle)
-screenInfo (S.Screen { S.workspace = ws, S.screenDetail = (SD s)}) = (ws, s)
+screenInfo S.Screen{ S.workspace = ws, S.screenDetail = (SD s)} = (ws, s)
 
 getWindowRectangle :: Window -> X Rectangle
 getWindowRectangle window
@@ -325,8 +325,7 @@ getNecessaryData :: Window
 getNecessaryData window ws floats
   = do r <- getWindowRectangle window
 
-       rs <- return (organizeClients ws window floats)
-             >>= mapM getWindowRectangle
+       rs <- mapM getWindowRectangle (organizeClients ws window floats)
 
        pointer <- getPointer window
 

XMonad/Hooks/PositionStoreHooks.hs

@@ -92,12 +92,12 @@ positionStoreInit mDecoTheme w  = withDisplay $ \d -> do
                                         (Rectangle (fi $ wa_x wa) (fi (wa_y wa) - fi decoH)
                                             (fi $ wa_width wa) (decoH + fi (wa_height wa))) sr' )
     where
-        randomIntOffset :: X (Int)
+        randomIntOffset :: X Int
         randomIntOffset = io $ randomRIO (42, 242)
 
 positionStoreEventHook :: Event -> X All
-positionStoreEventHook (DestroyWindowEvent {ev_window = w, ev_event_type = et}) = do
+positionStoreEventHook DestroyWindowEvent{ev_window = w, ev_event_type = et} = do
     when (et == destroyNotify) $
-        modifyPosStore (\ps -> posStoreRemove ps w)
+        modifyPosStore (`posStoreRemove` w)
     return (All True)
 positionStoreEventHook _ = return (All True)

XMonad/Hooks/RefocusLast.hs

@@ -281,8 +281,9 @@ getRecentsMap = XS.get >>= \(RecentsMap m) -> return m
 -- | Perform an X action dependent on successful lookup of the RecentWins for
 --   the specified workspace, or return a default value.
 withRecentsIn :: WorkspaceId -> a -> (Window -> Window -> X a) -> X a
-withRecentsIn tag dflt f = M.lookup tag <$> getRecentsMap
-                       >>= maybe (return dflt) (\(Recent lw cw) -> f lw cw)
+withRecentsIn tag dflt f = maybe (return dflt) (\(Recent lw cw) -> f lw cw)
+                         . M.lookup tag
+                       =<< getRecentsMap
 
 -- | The above specialised to the current workspace and unit.
 withRecents :: (Window -> Window -> X ()) -> X ()

XMonad/Hooks/ScreenCorners.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE DeriveDataTypeable, FlexibleInstances, MultiParamTypeClasses #-}
+{-# LANGUAGE DeriveDataTypeable, FlexibleInstances, MultiParamTypeClasses, TupleSections #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Hooks.ScreenCorners
@@ -63,13 +63,13 @@ addScreenCorner corner xF = do
     (win,xFunc) <- case find (\(_,(sc,_)) -> sc == corner) (M.toList m) of
 
                         Just (w, (_,xF')) -> return (w, xF' >> xF) -- chain X actions
-                        Nothing           -> flip (,) xF <$> createWindowAt corner
+                        Nothing           -> (, xF) <$> createWindowAt corner
 
     XS.modify $ \(ScreenCornerState m') -> ScreenCornerState $ M.insert win (corner,xFunc) m'
 
 -- | Add a list of @(ScreenCorner, X ())@ tuples
 addScreenCorners :: [ (ScreenCorner, X ()) ] -> X ()
-addScreenCorners = mapM_ (\(corner, xF) -> addScreenCorner corner xF)
+addScreenCorners = mapM_ (uncurry addScreenCorner)
 
 
 --------------------------------------------------------------------------------

XMonad/Hooks/ServerMode.hs

@@ -55,12 +55,12 @@ serverModeEventHook = serverModeEventHook' defaultCommands
 -- | serverModeEventHook' additionally takes an action to generate the list of
 -- commands.
 serverModeEventHook' :: X [(String,X ())] -> Event -> X All
-serverModeEventHook' cmdAction ev = serverModeEventHookF "XMONAD_COMMAND" (sequence_ . map helper . words) ev
+serverModeEventHook' cmdAction = serverModeEventHookF "XMONAD_COMMAND" (mapM_ helper . words)
         where helper cmd = do cl <- cmdAction
                               case lookup cmd (zip (map show [1 :: Integer ..]) cl) of
                                 Just (_,action) -> action
                                 Nothing         -> mapM_ (io . hPutStrLn stderr) . listOfCommands $ cl
-              listOfCommands cl = map (uncurry (++)) $ zip (map show ([1..] :: [Int])) $ map ((++) " - " . fst) cl
+              listOfCommands cl = zipWith (++) (map show [1 :: Int ..]) (map ((++) " - " . fst) cl)
 
 
 -- | Executes a command of the list when receiving its name via a special ClientMessageEvent.
@@ -75,7 +75,7 @@ serverModeEventHookCmd = serverModeEventHookCmd' defaultCommands
 
 -- | Additionally takes an action to generate the list of commands
 serverModeEventHookCmd' :: X [(String,X ())] -> Event -> X All
-serverModeEventHookCmd' cmdAction ev = serverModeEventHookF "XMONAD_COMMAND" (sequence_ . map helper . words) ev
+serverModeEventHookCmd' cmdAction = serverModeEventHookF "XMONAD_COMMAND" (mapM_ helper . words)
         where helper cmd = do cl <- cmdAction
                               fromMaybe (io $ hPutStrLn stderr ("Couldn't find command " ++ cmd)) (lookup cmd cl)
 
@@ -87,7 +87,7 @@ serverModeEventHookCmd' cmdAction ev = serverModeEventHookF "XMONAD_COMMAND" (se
 -- > xmonadctl -a XMONAD_PRINT "hello world"
 --
 serverModeEventHookF :: String -> (String -> X ()) -> Event -> X All
-serverModeEventHookF key func (ClientMessageEvent {ev_message_type = mt, ev_data = dt}) = do
+serverModeEventHookF key func ClientMessageEvent {ev_message_type = mt, ev_data = dt} = do
         d <- asks display
         atm <- io $ internAtom d key False
         when (mt == atm && dt /= []) $ do
@@ -95,6 +95,6 @@ serverModeEventHookF key func (ClientMessageEvent {ev_message_type = mt, ev_data
          cmd <- io $ getAtomName d atom
          case cmd of
               Just command -> func command
-              Nothing -> io $ hPutStrLn stderr ("Couldn't retrieve atom " ++ (show atom))
+              Nothing -> io $ hPutStrLn stderr ("Couldn't retrieve atom " ++ show atom)
         return (All True)
 serverModeEventHookF _ _ _ = return (All True)

XMonad/Hooks/ToggleHook.hs

@@ -62,7 +62,7 @@ _pp n f s st = (\b -> guard b >> Just (st s)) <$> _get n f
 
 {- The current state is kept here -}
 
-data HookState = HookState { hooks :: Map String (Bool, Bool) } deriving (Typeable, Read, Show)
+newtype HookState = HookState { hooks :: Map String (Bool, Bool) } deriving (Typeable, Read, Show)
 
 instance ExtensionClass HookState where
     initialValue = HookState empty

XMonad/Hooks/UrgencyHook.hs

@@ -1,5 +1,4 @@
-{-# LANGUAGE FlexibleContexts, MultiParamTypeClasses, TypeSynonymInstances, PatternGuards, DeriveDataTypeable,
-  FlexibleInstances #-}
+{-# LANGUAGE FlexibleContexts, MultiParamTypeClasses, DeriveDataTypeable, FlexibleInstances #-}
 
 -----------------------------------------------------------------------------
 -- |
@@ -196,7 +195,7 @@ import Foreign.C.Types (CLong)
 -- instead.
 withUrgencyHook :: (LayoutClass l Window, UrgencyHook h) =>
                    h -> XConfig l -> XConfig l
-withUrgencyHook hook conf = withUrgencyHookC hook urgencyConfig conf
+withUrgencyHook hook = withUrgencyHookC hook urgencyConfig
 
 -- | This lets you modify the defaults set in 'urgencyConfig'. An example:
 --
@@ -211,7 +210,7 @@ withUrgencyHookC hook urgConf conf = conf {
         startupHook = cleanupStaleUrgents >> startupHook conf
     }
 
-data Urgents = Urgents { fromUrgents :: [Window] } deriving (Read,Show,Typeable)
+newtype Urgents = Urgents { fromUrgents :: [Window] } deriving (Read,Show,Typeable)
 
 onUrgents :: ([Window] -> [Window]) -> Urgents -> Urgents
 onUrgents f = Urgents . f . fromUrgents
@@ -283,7 +282,7 @@ withUrgents f = readUrgents >>= f
 cleanupStaleUrgents :: X ()
 cleanupStaleUrgents = withWindowSet $ \ws -> do
     adjustUrgents (filter (`W.member` ws))
-    adjustReminders (filter $ ((`W.member` ws) . window))
+    adjustReminders (filter ((`W.member` ws) . window))
 
 adjustUrgents :: ([Window] -> [Window]) -> X ()
 adjustUrgents = XS.modify . onUrgents
@@ -324,7 +323,7 @@ changeNetWMState dpy w f = do
 
 -- | Add an atom to the _NET_WM_STATE property.
 addNetWMState :: Display -> Window -> Atom -> X ()
-addNetWMState dpy w atom = changeNetWMState dpy w $ ((fromIntegral atom):)
+addNetWMState dpy w atom = changeNetWMState dpy w (fromIntegral atom :)
 
 -- | Remove an atom from the _NET_WM_STATE property.
 removeNetWMState :: Display -> Window -> Atom -> X ()
@@ -356,7 +355,7 @@ handleEvent wuh event =
       PropertyEvent { ev_event_type = t, ev_atom = a, ev_window = w } ->
           when (t == propertyNotify && a == wM_HINTS) $ withDisplay $ \dpy -> do
               WMHints { wmh_flags = flags } <- io $ getWMHints dpy w
-              if (testBit flags urgencyHintBit) then markUrgent w else markNotUrgent w
+              if testBit flags urgencyHintBit then markUrgent w else markNotUrgent w
       -- Window destroyed
       DestroyWindowEvent {ev_window = w} ->
           markNotUrgent w
@@ -380,7 +379,7 @@ handleEvent wuh event =
           mapM_ handleReminder =<< readReminders
       where handleReminder reminder = handleTimer (timer reminder) event $ reminderHook wuh reminder
             markUrgent w = do
-                adjustUrgents (\ws -> if elem w ws then ws else w : ws)
+                adjustUrgents (\ws -> if w `elem` ws then ws else w : ws)
                 callUrgencyHook wuh w
                 userCodeDef () =<< asks (logHook . config)
             markNotUrgent w = do
@@ -423,9 +422,9 @@ cleanupUrgents sw = clearUrgents' =<< suppressibleWindows sw
 clearUrgents' :: [Window] -> X ()
 clearUrgents' ws = do
     a_da <- getAtom "_NET_WM_STATE_DEMANDS_ATTENTION"
-    dpy <- withDisplay (\dpy -> return dpy)
+    dpy <- withDisplay return
     mapM_ (\w -> removeNetWMState dpy w a_da) ws
-    adjustUrgents (\\ ws) >> adjustReminders (filter $ ((`notElem` ws) . window))
+    adjustUrgents (\\ ws) >> adjustReminders (filter ((`notElem` ws) . window))
 
 suppressibleWindows :: SuppressWhen -> X [Window]
 suppressibleWindows Visible  = gets $ S.toList . mapped
@@ -491,7 +490,7 @@ instance UrgencyHook FocusHook where
 
 borderUrgencyHook :: String -> Window -> X ()
 borderUrgencyHook = urgencyHook . BorderUrgencyHook
-data BorderUrgencyHook = BorderUrgencyHook { urgencyBorderColor :: !String }
+newtype BorderUrgencyHook = BorderUrgencyHook { urgencyBorderColor :: String }
                        deriving (Read, Show)
 
 instance UrgencyHook BorderUrgencyHook where

XMonad/Hooks/WallpaperSetter.hs

@@ -35,7 +35,6 @@ import System.FilePath ((</>))
 import System.Random (randomRIO)
 
 import qualified Data.Map as M
-import Data.Ord (comparing)
 
 -- $usage
 -- This module requires imagemagick and feh to be installed, as these are utilized
@@ -176,7 +175,7 @@ completeWPConf (WallpaperConf dir (WallpaperList ws)) = do
 getVisibleWorkspaces :: X [WorkspaceId]
 getVisibleWorkspaces = do
   winset <- gets windowset
-  return $ map (S.tag . S.workspace) . sortBy (comparing S.screen) $ S.current winset : S.visible winset
+  return $ map (S.tag . S.workspace) . sortOn S.screen $ S.current winset : S.visible winset
 
 getPicPathsAndWSRects :: WallpaperConf -> X [(Rectangle, FilePath)]
 getPicPathsAndWSRects wpconf = do
@@ -185,7 +184,7 @@ getPicPathsAndWSRects wpconf = do
   visws <- getVisibleWorkspaces
   let visscr = S.current winset : S.visible winset
       visrects = M.fromList $ map (\x -> ((S.tag . S.workspace) x, S.screenDetail x)) visscr
-      hasPicAndIsVisible (n, mp) = n `elem` visws && (isJust mp)
+      hasPicAndIsVisible (n, mp) = n `elem` visws && isJust mp
       getRect tag = screenRect $ fromJust $ M.lookup tag visrects
       foundpaths = map (\(n,Just p)->(getRect n,p)) $ filter hasPicAndIsVisible paths
   return foundpaths
@@ -224,4 +223,4 @@ layerCommand (rect, path) = do
     Just rotate -> let size = show (rect_width rect) ++ "x" ++ show (rect_height rect) in
                      " \\( '"++path++"' "++(if rotate then "-rotate 90 " else "")
                       ++ " -scale "++size++"^ -gravity center -extent "++size++" +gravity \\)"
-                      ++ " -geometry +" ++ (show $rect_x rect) ++ "+" ++ (show $rect_y rect) ++ " -composite "
+                      ++ " -geometry +" ++ show (rect_x rect) ++ "+" ++ show (rect_y rect) ++ " -composite "

XMonad/Hooks/XPropManage.hs

@@ -56,7 +56,7 @@ import XMonad.Prelude (Endo (..), chr)
 -- should work fine. Others might not work.
 --
 
-type XPropMatch = ([(Atom, [String] -> Bool)], (Window -> X (WindowSet -> WindowSet)))
+type XPropMatch = ([(Atom, [String] -> Bool)], Window -> X (WindowSet -> WindowSet))
 
 pmX :: (Window -> X ()) -> Window -> X (WindowSet -> WindowSet)
 pmX f w = f w >> return id
@@ -71,10 +71,10 @@ xPropManageHook tms = mconcat $ map propToHook tms
       mkQuery (a, tf)    = fmap tf (getQuery a)
       mkHook func        = ask >>= Query . lift . fmap Endo . func
 
-getProp :: Display -> Window -> Atom -> X ([String])
+getProp :: Display -> Window -> Atom -> X [String]
 getProp d w p = do
     prop <- io $ E.catch (getTextProperty d w p >>= wcTextPropertyToTextList d) (\(_ :: IOException) -> return [[]])
-    let filt q | q == wM_COMMAND = concat . map splitAtNull
+    let filt q | q == wM_COMMAND = concatMap splitAtNull
                | otherwise       = id
     return (filt p prop)
 
@@ -82,7 +82,7 @@ getQuery ::  Atom -> Query [String]
 getQuery p = ask >>= \w ->  Query . lift $ withDisplay $ \d -> getProp d w p
 
 splitAtNull :: String -> [String]
-splitAtNull s = case dropWhile (== (chr 0)) s of
+splitAtNull s = case dropWhile (== chr 0) s of
     "" -> []
     s' -> w : splitAtNull s''
-          where (w, s'') = break (== (chr 0)) s'
+          where (w, s'') = break (== chr 0) s'

XMonad/Layout/Accordion.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses #-}
 
 -----------------------------------------------------------------------------
 -- |

XMonad/Layout/AutoMaster.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, TypeSynonymInstances, FlexibleContexts #-}
+{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, FlexibleContexts #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Layout.AutoMaster
@@ -20,11 +20,13 @@ module XMonad.Layout.AutoMaster (
                              -- $usage
                              autoMaster, AutoMaster
                             ) where
-import XMonad.Prelude
-
 import XMonad
-import qualified XMonad.StackSet as W
 import XMonad.Layout.LayoutModifier
+import XMonad.Prelude
+import qualified XMonad.StackSet as W
+
+import Control.Arrow (first)
+
 
 -- $usage
 -- This module defines layout modifier named autoMaster. It separates
@@ -57,7 +59,7 @@ autoMess :: AutoMaster a -> SomeMessage -> Maybe (AutoMaster a)
 autoMess (AutoMaster k bias delta) m = msum [fmap resize (fromMessage m),
                                              fmap incmastern (fromMessage m)]
     where incmastern (IncMasterN d) = AutoMaster (max 1 (k+d)) bias delta
-          resize Expand = AutoMaster k (min ( 0.4)  $ bias+delta) delta
+          resize Expand = AutoMaster k (min 0.4  $ bias+delta) delta
           resize Shrink = AutoMaster k (max (-0.4)  $ bias-delta) delta
 
 -- | Main layout function
@@ -74,32 +76,32 @@ autoLayout k bias wksp rect = do
     if null ws then
         runLayout wksp rect
         else
-          if (n<=k) then
-              return ((divideRow rect ws),Nothing)
+          if n<=k then
+              return (divideRow rect ws,Nothing)
               else do
               let master = take k ws
-              let filtStack = stack >>= W.filter (\w -> not (w `elem` master))
+              let filtStack = stack >>= W.filter (`notElem` master)
               wrs <- runLayout (wksp {W.stack = filtStack}) (slaveRect rect n bias)
-              return ((divideRow (masterRect rect n bias) master) ++ (fst wrs),
-                      snd wrs)
+              return $ first (divideRow (masterRect rect n bias) master ++)
+                             wrs
 
 -- | Calculates height of master area, depending on number of windows.
 masterHeight :: Int -> Float -> Float
-masterHeight n bias = (calcHeight n) + bias
+masterHeight n bias = calcHeight n + bias
     where calcHeight :: Int -> Float
           calcHeight 1 = 1.0
-          calcHeight m = if (m<9) then (43/45) - (fromIntegral m)*(7/90) else (1/3)
+          calcHeight m = if m<9 then (43/45) - fromIntegral m*(7/90) else 1/3
 
 -- | Rectangle for master area
 masterRect :: Rectangle -> Int -> Float -> Rectangle
 masterRect (Rectangle sx sy sw sh) n bias = Rectangle sx sy sw h
-    where h = round $ (fromIntegral sh)*(masterHeight n bias)
+    where h = round $ fromIntegral sh*masterHeight n bias
 
 -- | Rectangle for slave area
 slaveRect :: Rectangle -> Int -> Float -> Rectangle
 slaveRect (Rectangle sx sy sw sh) n bias = Rectangle sx (sy+mh) sw h
-    where mh = round $ (fromIntegral sh)*(masterHeight n bias)
-          h  = round $ (fromIntegral sh)*(1-masterHeight n bias)
+    where mh = round $ fromIntegral sh*masterHeight n bias
+          h  = round $ fromIntegral sh*(1-masterHeight n bias)
 
 -- | Divide rectangle between windows
 divideRow :: Rectangle -> [a] -> [(a, Rectangle)]
@@ -120,4 +122,3 @@ autoMaster :: LayoutClass l a =>
               l a ->
               ModifiedLayout AutoMaster l a
 autoMaster nmaster delta = ModifiedLayout (AutoMaster nmaster 0 delta)
-

XMonad/Layout/AvoidFloats.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE PatternGuards, FlexibleContexts, FlexibleInstances, MultiParamTypeClasses, TypeSynonymInstances, ParallelListComp, DeriveDataTypeable #-}
+{-# LANGUAGE PatternGuards, FlexibleContexts, FlexibleInstances, MultiParamTypeClasses, DeriveDataTypeable, TupleSections #-}
 
 -----------------------------------------------------------------------------
 -- |
@@ -26,7 +26,7 @@ module XMonad.Layout.AvoidFloats (
 
 import XMonad
 import XMonad.Layout.LayoutModifier
-import XMonad.Prelude (fi, maximumBy, maybeToList, sortBy)
+import XMonad.Prelude (fi, mapMaybe, maximumBy, sortOn)
 import qualified XMonad.StackSet as W
 
 import Data.Ord
@@ -107,10 +107,10 @@ instance LayoutModifier AvoidFloats Window where
     modifyLayoutWithUpdate lm w r = withDisplay $ \d -> do
         floating <- gets $ W.floating . windowset
         case cache lm of
-            Just (key, mer) | key == (floating,r) -> flip (,) Nothing <$> runLayout w mer
+            Just (key, mer) | key == (floating,r) -> (, Nothing) <$> runLayout w mer
             _ -> do rs <- io $ map toRect <$> mapM (getWindowAttributes d) (filter shouldAvoid $ M.keys floating)
                     let mer = maximumBy (comparing area) $ filter bigEnough $ maxEmptyRectangles r rs
-                    flip (,) (Just $ pruneWindows $ lm { cache = Just ((floating,r),mer) }) <$> runLayout w mer
+                    (, Just $ pruneWindows $ lm { cache = Just ((floating,r),mer) }) <$> runLayout w mer
         where
             toRect :: WindowAttributes -> Rectangle
             toRect wa = let b = fi $ wa_border_width wa
@@ -122,9 +122,9 @@ instance LayoutModifier AvoidFloats Window where
             shouldAvoid a = avoidAll lm || a `S.member` chosen lm
 
     pureMess lm m
-        | Just (AvoidFloatToggle) <- fromMessage m =                               Just $ lm { avoidAll = not (avoidAll lm), cache = Nothing }
+        | Just AvoidFloatToggle <- fromMessage m =                                 Just $ lm { avoidAll = not (avoidAll lm), cache = Nothing }
         | Just (AvoidFloatSet s) <- fromMessage m, s /= avoidAll lm =              Just $ lm { avoidAll = s, cache = Nothing }
-        | Just (AvoidFloatClearItems) <- fromMessage m =                           Just $ lm { chosen = S.empty, cache = Nothing }
+        | Just AvoidFloatClearItems <- fromMessage m =                             Just $ lm { chosen = S.empty, cache = Nothing }
         | Just (AvoidFloatAddItem a) <- fromMessage m, a `S.notMember` chosen lm = Just $ lm { chosen = S.insert a (chosen lm), cache = Nothing }
         | Just (AvoidFloatRemoveItem a) <- fromMessage m, a `S.member` chosen lm = Just $ lm { chosen = S.delete a (chosen lm), cache = Nothing }
         | Just (AvoidFloatToggleItem a) <- fromMessage m =                         let op = if a `S.member` chosen lm then S.delete else S.insert
@@ -134,7 +134,7 @@ instance LayoutModifier AvoidFloats Window where
 pruneWindows :: AvoidFloats Window -> AvoidFloats Window
 pruneWindows lm = case cache lm of
     Nothing -> lm
-    Just ((floating,_),_) -> lm { chosen = S.filter (flip M.member floating) (chosen lm) }
+    Just ((floating,_),_) -> lm { chosen = S.filter (`M.member` floating) (chosen lm) }
 
 -- | Find all maximum empty rectangles (MERs) that are axis aligned. This is
 --   done in O(n^2) time using a modified version of the algoprithm MERAlg 1
@@ -144,9 +144,9 @@ maxEmptyRectangles :: Rectangle -> [Rectangle] -> [Rectangle]
 maxEmptyRectangles br rectangles = filter (\a -> area a > 0) $ upAndDownEdge ++ noneOrUpEdge ++ downEdge
     where
         upAndDownEdge = findGaps br rectangles
-        noneOrUpEdge = concat $ map (everyLower br bottoms) bottoms
-        downEdge = concat $ map maybeToList $ map (bottomEdge br bottoms) bottoms
-        bottoms = sortBy (comparing bottom) $ splitContainers rectangles
+        noneOrUpEdge = concatMap (everyLower br bottoms) bottoms
+        downEdge = mapMaybe (bottomEdge br bottoms) bottoms
+        bottoms = sortOn bottom $ splitContainers rectangles
 
 everyLower :: Rectangle -> [Rectangle] -> Rectangle -> [Rectangle]
 everyLower br bottoms r = let (rs, boundLeft, boundRight, boundRects) = foldr (everyUpper r) ([], left br, right br, reverse bottoms) bottoms
@@ -177,8 +177,8 @@ shrinkBounds' mr r (boundLeft, boundRight)
 
 bottomEdge :: Rectangle -> [Rectangle] -> Rectangle -> Maybe Rectangle
 bottomEdge br bottoms r = let rs = filter (\a -> bottom r < bottom a && top a < bottom br) bottoms
-                              boundLeft = maximum $ left br : (filter (< right r) $ map right rs)
-                              boundRight = minimum $ right br : (filter (> left r) $ map left rs)
+                              boundLeft = maximum $ left br : filter (< right r) (map right rs)
+                              boundRight = minimum $ right br : filter (> left r) (map left rs)
                           in if any (\a -> left a <= left r && right r <= right a) rs
                              then Nothing
                              else mkRect boundLeft boundRight (bottom r) (bottom br)
@@ -186,11 +186,11 @@ bottomEdge br bottoms r = let rs = filter (\a -> bottom r < bottom a && top a <
 -- | Split rectangles that horizontally fully contains another rectangle
 --   without sharing either the left or right side.
 splitContainers :: [Rectangle] -> [Rectangle]
-splitContainers rects = splitContainers' [] $ sortBy (comparing rect_width) rects
+splitContainers rects = splitContainers' [] $ sortOn rect_width rects
     where
         splitContainers' :: [Rectangle] -> [Rectangle] -> [Rectangle]
         splitContainers' res [] = res
-        splitContainers' res (r:rs) = splitContainers' (r:res) $ concat $ map (doSplit r) rs
+        splitContainers' res (r:rs) = splitContainers' (r:res) $ concatMap (doSplit r) rs
 
         doSplit :: Rectangle -> Rectangle -> [Rectangle]
         doSplit guide r
@@ -206,7 +206,7 @@ findGaps
     :: Rectangle    -- ^ Bounding rectangle.
     -> [Rectangle]  -- ^ List of all rectangles that can cover areas in the bounding rectangle.
     -> [Rectangle]
-findGaps br rs = let (gaps,end) = foldr findGaps' ([], left br) $ sortBy (flip $ comparing left) $ filter inBounds rs
+findGaps br rs = let (gaps,end) = foldr findGaps' ([], left br) $ sortOn (Down . left) $ filter inBounds rs
                      lastgap = mkRect end (right br) (top br) (bottom br)
                  in lastgap?:gaps
     where

XMonad/Layout/BinaryColumn.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Layout.BinaryColumn
@@ -86,7 +86,7 @@ columnLayout (BinaryColumn scale min_size) rect stack = zip ws rects
           m_fl = fromIntegral m
           m_prev_fl = fromIntegral (m + 1)
           div_test = min divide m_prev_fl
-          value_test = round ((fromIntegral size) / div_test) :: Integer
+          value_test = round (fromIntegral size / div_test) :: Integer
           value_max = size - toInteger (min_size * m)
           (value, divide_next, no_room) =
             if value_test < value_max then
@@ -101,7 +101,7 @@ columnLayout (BinaryColumn scale min_size) rect stack = zip ws rects
         -- simply create an even grid with the remaining space.
         f m size divide True = let
           divide_next = fromIntegral m
-          value_even = ((fromIntegral size) / divide)
+          value_even = (fromIntegral size / divide)
           value = round value_even :: Integer
 
           m_next = m - 1
@@ -112,21 +112,21 @@ columnLayout (BinaryColumn scale min_size) rect stack = zip ws rects
          n_init size_init divide_init False
       where
         n_init = n - 1
-        size_init = (toInteger (rect_height rect))
+        size_init = toInteger (rect_height rect)
         divide_init =
           if scale_abs == 0.0 then
-            (fromIntegral n)
+            fromIntegral n
           else
-            (1.0 / (0.5 * scale_abs))
+            1.0 / (0.5 * scale_abs)
 
     heights =
-      if (scale < 0.0) then
+      if scale < 0.0 then
         Data.List.reverse (take n heights_noflip)
       else
         heights_noflip
 
     ys = [fromIntegral $ sum $ take k heights | k <- [0..n - 1]]
-    rects = map (mkRect rect) $ zip heights ys
+    rects = zipWith (curry (mkRect rect)) heights ys
 
 mkRect :: XMonad.Rectangle
   -> (Integer,XMonad.Position)

XMonad/Layout/BinarySpacePartition.hs

@@ -157,7 +157,7 @@ instance Message SelectMoveNode
 data Axis = Horizontal | Vertical deriving (Show, Read, Eq)
 
 -- | Message for shifting window by splitting its neighbour
-data SplitShiftDirectional = SplitShift Direction1D deriving Typeable
+newtype SplitShiftDirectional = SplitShift Direction1D deriving Typeable
 instance Message SplitShiftDirectional
 
 oppositeDirection :: Direction2D -> Direction2D
@@ -253,9 +253,7 @@ goSibling z@(_, LeftCrumb _ _:_) = Just z >>= goUp >>= goRight
 goSibling z@(_, RightCrumb _ _:_) = Just z >>= goUp >>= goLeft
 
 top :: Zipper a -> Zipper a
-top z = case goUp z of
-          Nothing -> z
-          Just z' -> top z'
+top z = maybe z top (goUp z)
 
 toTree :: Zipper a -> Tree a
 toTree = fst . top
@@ -283,10 +281,10 @@ removeCurrent :: Zipper a -> Maybe (Zipper a)
 removeCurrent (Leaf _, LeftCrumb _ r:cs) = Just (r, cs)
 removeCurrent (Leaf _, RightCrumb _ l:cs) = Just (l, cs)
 removeCurrent (Leaf _, []) = Nothing
-removeCurrent (Node _ (Leaf _) r@(Node _ _ _), cs) = Just (r, cs)
-removeCurrent (Node _ l@(Node _ _ _) (Leaf _), cs) = Just (l, cs)
+removeCurrent (Node _ (Leaf _) r@Node{}, cs) = Just (r, cs)
+removeCurrent (Node _ l@Node{} (Leaf _), cs) = Just (l, cs)
 removeCurrent (Node _ (Leaf _) (Leaf _), cs) = Just (Leaf 0, cs)
-removeCurrent z@(Node _ _ _, _) = goLeft z >>= removeCurrent
+removeCurrent z@(Node{}, _) = goLeft z >>= removeCurrent
 
 rotateCurrent :: Zipper Split -> Maybe (Zipper Split)
 rotateCurrent l@(_, []) = Just l
@@ -297,23 +295,23 @@ swapCurrent l@(_, []) = Just l
 swapCurrent (n, c:cs) = Just (n, swapCrumb c:cs)
 
 insertLeftLeaf :: Tree Split -> Zipper Split -> Maybe (Zipper Split)
-insertLeftLeaf (Leaf n) ((Node x l r), crumb:cs) = Just (Node (Split (oppositeAxis . axis . parentVal $ crumb) 0.5) (Leaf n) (Node x l r), crumb:cs)
+insertLeftLeaf (Leaf n) (Node x l r, crumb:cs) = Just (Node (Split (oppositeAxis . axis . parentVal $ crumb) 0.5) (Leaf n) (Node x l r), crumb:cs)
 insertLeftLeaf (Leaf n) (Leaf x, crumb:cs) = Just (Node (Split (oppositeAxis . axis . parentVal $ crumb) 0.5) (Leaf n) (Leaf x), crumb:cs)
-insertLeftLeaf (Node _ _ _) z = Just z
+insertLeftLeaf Node{} z = Just z
 insertLeftLeaf _ _ = Nothing
 
 insertRightLeaf :: Tree Split -> Zipper Split -> Maybe (Zipper Split)
-insertRightLeaf (Leaf n) ((Node x l r), crumb:cs) = Just (Node (Split (oppositeAxis . axis . parentVal $ crumb) 0.5) (Node x l r) (Leaf n), crumb:cs)
+insertRightLeaf (Leaf n) (Node x l r, crumb:cs) = Just (Node (Split (oppositeAxis . axis . parentVal $ crumb) 0.5) (Node x l r) (Leaf n), crumb:cs)
 insertRightLeaf (Leaf n) (Leaf x, crumb:cs) = Just (Node (Split (oppositeAxis . axis . parentVal $ crumb) 0.5) (Leaf x) (Leaf n), crumb:cs)
-insertRightLeaf (Node _ _ _) z = Just z
+insertRightLeaf Node{} z = Just z
 insertRightLeaf _ _ = Nothing
 
 findRightLeaf :: Zipper Split -> Maybe (Zipper Split)
-findRightLeaf n@(Node _ _ _, _) = goRight n >>= findRightLeaf
+findRightLeaf n@(Node{}, _) = goRight n >>= findRightLeaf
 findRightLeaf l@(Leaf _, _) = Just l
 
 findLeftLeaf :: Zipper Split -> Maybe (Zipper Split)
-findLeftLeaf n@(Node _ _ _, _) = goLeft n
+findLeftLeaf n@(Node{}, _) = goLeft n
 findLeftLeaf l@(Leaf _, _) = Just l
 
 findTheClosestLeftmostLeaf :: Zipper Split -> Maybe (Zipper Split)
@@ -508,7 +506,7 @@ toNodeRef l (Just (_, cs)) = NodeRef l (reverse $ map crumbToDir cs) []
 nodeRefToLeaf :: NodeRef -> Maybe (Zipper a) -> Maybe Int
 nodeRefToLeaf n (Just z) = case goToNode n z of
   Just (Leaf l, _) -> Just l
-  Just (Node _ _ _, _) -> Nothing
+  Just (Node{}, _) -> Nothing
   Nothing -> Nothing
 nodeRefToLeaf _ Nothing = Nothing
 
@@ -693,13 +691,13 @@ replaceFloating wsm = do
 -- some helpers to filter windows
 --
 getFloating :: X [Window]
-getFloating = (M.keys . W.floating) <$> gets windowset -- all floating windows
+getFloating = M.keys . W.floating <$> gets windowset -- all floating windows
 
 getStackSet :: X (Maybe (W.Stack Window))
-getStackSet = (W.stack . W.workspace . W.current) <$> gets windowset -- windows on this WS (with floating)
+getStackSet = W.stack . W.workspace . W.current <$> gets windowset -- windows on this WS (with floating)
 
 getScreenRect :: X Rectangle
-getScreenRect = (screenRect . W.screenDetail . W.current) <$> gets windowset
+getScreenRect = screenRect . W.screenDetail . W.current <$> gets windowset
 
 withoutFloating :: [Window] -> Maybe (W.Stack Window) -> Maybe (W.Stack Window)
 withoutFloating fs = maybe Nothing (unfloat fs)
@@ -772,8 +770,8 @@ instance LayoutClass BinarySpacePartition Window where
           splitShift (SplitShift dir) = resetFoc $ splitShiftNth dir b
 
           b = numerateLeaves b_orig
-          resetFoc bsp = bsp{getFocusedNode=(getFocusedNode bsp){refLeaf=(-1)}
-                            ,getSelectedNode=(getSelectedNode bsp){refLeaf=(-1)}}
+          resetFoc bsp = bsp{getFocusedNode=(getFocusedNode bsp){refLeaf= -1}
+                            ,getSelectedNode=(getSelectedNode bsp){refLeaf= -1}}
 
   description _  = "BSP"
 
@@ -850,8 +848,8 @@ createBorder (Rectangle wx wy ww wh) c = do
               ]
   ws <- mapM (\r -> createNewWindow r Nothing bc False) rects
   showWindows ws
-  maybe Nothing (\s -> Just s{W.down=W.down s ++ ws}) <$> getStackSet >>= replaceStack
-  M.union (M.fromList $ zip ws $ map toRR rects) . W.floating . windowset <$> get >>= replaceFloating
+  replaceStack . maybe Nothing (\s -> Just s{W.down=W.down s ++ ws}) =<< getStackSet
+  replaceFloating . M.union (M.fromList $ zip ws $ map toRR rects) . W.floating . windowset =<< get
   modify (\s -> s{mapped=mapped s `S.union` S.fromList ws})
   -- show <$> mapM isClient ws >>= debug
   return ws
@@ -861,6 +859,6 @@ createBorder (Rectangle wx wy ww wh) c = do
 removeBorder :: [Window] -> X ()
 removeBorder ws = do
   modify (\s -> s{mapped = mapped s `S.difference` S.fromList ws})
-  flip (foldl (flip M.delete)) ws . W.floating . windowset <$> get >>= replaceFloating
-  maybe Nothing (\s -> Just s{W.down=W.down s \\ ws}) <$> getStackSet >>= replaceStack
+  replaceFloating . flip (foldl (flip M.delete)) ws . W.floating . windowset =<< get
+  replaceStack . maybe Nothing (\s -> Just s{W.down=W.down s \\ ws}) =<< getStackSet
   deleteWindows ws

XMonad/Layout/BorderResize.hs

@@ -57,7 +57,7 @@ data BorderInfo = BI { bWin :: Window,
 
 type RectWithBorders = (Rectangle, [BorderInfo])
 
-data BorderResize a = BR (M.Map Window RectWithBorders) deriving (Show, Read)
+newtype BorderResize a = BR (M.Map Window RectWithBorders) deriving (Show, Read)
 
 brBorderSize :: Dimension
 brBorderSize = 2
@@ -99,7 +99,7 @@ instance LayoutModifier BorderResize Window where
 
 compileWrs :: M.Map Window RectWithBorders -> [Window] -> [(Window, Rectangle)]
 compileWrs wrsThisTime correctOrder = let wrs = reorder (M.toList wrsThisTime) correctOrder
-                                      in concat $ map compileWr wrs
+                                      in concatMap compileWr wrs
 
 compileWr :: (Window, RectWithBorders) -> [(Window, Rectangle)]
 compileWr (w, (r, borderInfos)) =
@@ -109,7 +109,7 @@ compileWr (w, (r, borderInfos)) =
 handleGone :: M.Map Window RectWithBorders -> X ()
 handleGone wrsGone = mapM_ deleteWindow borderWins
     where
-        borderWins = map bWin . concat . map snd . M.elems $ wrsGone
+        borderWins = map bWin . concatMap snd . M.elems $ wrsGone
 
 handleAppeared :: M.Map Window Rectangle -> X (M.Map Window RectWithBorders)
 handleAppeared wrsAppeared = do
@@ -124,58 +124,58 @@ handleSingleAppeared (w, r) = do
     return (w, (r, borderInfos))
 
 handleStillThere :: M.Map Window (Maybe Rectangle, RectWithBorders) -> M.Map Window RectWithBorders
-handleStillThere wrsStillThere = M.map handleSingleStillThere wrsStillThere
+handleStillThere = M.map handleSingleStillThere
 
 handleSingleStillThere :: (Maybe Rectangle, RectWithBorders) -> RectWithBorders
 handleSingleStillThere (Nothing, entry) = entry
 handleSingleStillThere (Just rCurrent, (_, borderInfos)) = (rCurrent, updatedBorderInfos)
     where
         changedBorderBlueprints = prepareBorders rCurrent
-        updatedBorderInfos = map updateBorderInfo . zip borderInfos $ changedBorderBlueprints
+        updatedBorderInfos = zipWith (curry updateBorderInfo) borderInfos changedBorderBlueprints
           -- assuming that the four borders are always in the same order
 
 updateBorderInfo :: (BorderInfo, BorderBlueprint) -> BorderInfo
 updateBorderInfo (borderInfo, (r, _, _)) = borderInfo { bRect = r }
 
 createBorderLookupTable :: M.Map Window RectWithBorders -> [(Window, (BorderType, Window, Rectangle))]
-createBorderLookupTable wrsLastTime = concat $ map processSingleEntry $ M.toList wrsLastTime
+createBorderLookupTable wrsLastTime = concatMap processSingleEntry (M.toList wrsLastTime)
     where
         processSingleEntry :: (Window, RectWithBorders) -> [(Window, (BorderType, Window, Rectangle))]
         processSingleEntry (w, (r, borderInfos)) = for borderInfos $ \bi -> (bWin bi, (bType bi, w, r))
 
 prepareBorders :: Rectangle -> [BorderBlueprint]
 prepareBorders (Rectangle x y wh ht) =
-    [((Rectangle (x + fi wh - fi brBorderSize) y brBorderSize ht), xC_right_side , RightSideBorder),
-     ((Rectangle x y brBorderSize ht)                            , xC_left_side  , LeftSideBorder),
-     ((Rectangle x y wh brBorderSize)                            , xC_top_side   , TopSideBorder),
-     ((Rectangle x (y + fi ht - fi brBorderSize) wh brBorderSize), xC_bottom_side, BottomSideBorder)
+    [(Rectangle (x + fi wh - fi brBorderSize) y brBorderSize ht, xC_right_side , RightSideBorder),
+     (Rectangle x y brBorderSize ht                            , xC_left_side  , LeftSideBorder),
+     (Rectangle x y wh brBorderSize                            , xC_top_side   , TopSideBorder),
+     (Rectangle x (y + fi ht - fi brBorderSize) wh brBorderSize, xC_bottom_side, BottomSideBorder)
     ]
 
 handleResize :: [(Window, (BorderType, Window, Rectangle))] -> Event -> X ()
 handleResize borders ButtonEvent { ev_window = ew, ev_event_type = et }
     | et == buttonPress, Just edge <- lookup ew borders =
     case edge of
-        (RightSideBorder, hostWin, (Rectangle hx hy _ hht)) ->
+        (RightSideBorder, hostWin, Rectangle hx hy _ hht) ->
             mouseDrag (\x _ -> do
                             let nwh = max 1 $ fi (x - hx)
                                 rect = Rectangle hx hy nwh hht
                             focus hostWin
                             when (x - hx > 0) $ sendMessage (SetGeometry rect)) (focus hostWin)
-        (LeftSideBorder, hostWin, (Rectangle hx hy hwh hht)) ->
+        (LeftSideBorder, hostWin, Rectangle hx hy hwh hht) ->
             mouseDrag (\x _ -> do
-                            let nx = max 0 $ min (hx + fi hwh) $ x
+                            let nx = max 0 $ min (hx + fi hwh) x
                                 nwh = max 1 $ hwh + fi (hx - x)
                                 rect = Rectangle nx hy nwh hht
                             focus hostWin
                             when (x < hx + fi hwh) $ sendMessage (SetGeometry rect)) (focus hostWin)
-        (TopSideBorder, hostWin, (Rectangle hx hy hwh hht)) ->
+        (TopSideBorder, hostWin, Rectangle hx hy hwh hht) ->
             mouseDrag (\_ y -> do
-                            let ny = max 0 $ min (hy + fi hht) $ y
+                            let ny = max 0 $ min (hy + fi hht) y
                                 nht = max 1 $ hht + fi (hy - y)
                                 rect = Rectangle hx ny hwh nht
                             focus hostWin
                             when (y < hy + fi hht) $ sendMessage (SetGeometry rect)) (focus hostWin)
-        (BottomSideBorder, hostWin, (Rectangle hx hy hwh _)) ->
+        (BottomSideBorder, hostWin, Rectangle hx hy hwh _) ->
             mouseDrag (\_ y -> do
                             let nht = max 1 $ fi (y - hy)
                                 rect = Rectangle hx hy hwh nht
@@ -183,7 +183,7 @@ handleResize borders ButtonEvent { ev_window = ew, ev_event_type = et }
                             when (y - hy > 0) $ sendMessage (SetGeometry rect)) (focus hostWin)
 handleResize _ _ = return ()
 
-createBorder :: BorderBlueprint -> X (BorderInfo)
+createBorder :: BorderBlueprint -> X BorderInfo
 createBorder (borderRect, borderCursor, borderType) = do
     borderWin <- createInputWindow borderCursor borderRect
     return BI { bWin = borderWin, bRect = borderRect, bType = borderType }
@@ -214,10 +214,10 @@ for = flip map
 
 reorder :: (Eq a) => [(a, b)] -> [a] -> [(a, b)]
 reorder wrs order =
-    let ordered = concat $ map (pickElem wrs) order
-        rest = filter (\(w, _) -> not (w `elem` order)) wrs
+    let ordered = concatMap (pickElem wrs) order
+        rest = filter (\(w, _) -> w `notElem` order) wrs
     in ordered ++ rest
     where
-        pickElem list e = case (lookup e list) of
+        pickElem list e = case lookup e list of
                                 Just result -> [(e, result)]
                                 Nothing -> []

XMonad/Layout/BoringWindows.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TypeSynonymInstances, MultiParamTypeClasses, DeriveDataTypeable #-}
+{-# LANGUAGE MultiParamTypeClasses, DeriveDataTypeable #-}
 {-# LANGUAGE PatternGuards, FlexibleContexts, FlexibleInstances #-}
 -----------------------------------------------------------------------------
 -- |
@@ -36,7 +36,7 @@ import XMonad.Layout.LayoutModifier(ModifiedLayout(..),
                                     LayoutModifier(handleMessOrMaybeModifyIt, redoLayout))
 import XMonad(Typeable, LayoutClass, Message, X, fromMessage,
               broadcastMessage, sendMessage, windows, withFocused, Window)
-import XMonad.Prelude (fromMaybe, listToMaybe, maybeToList, union, (\\))
+import XMonad.Prelude (find, fromMaybe, listToMaybe, maybeToList, union, (\\))
 import XMonad.Util.Stack (reverseS)
 import qualified Data.Map as M
 import qualified XMonad.StackSet as W
@@ -110,13 +110,13 @@ boringAuto :: (LayoutClass l a, Eq a) => l a -> ModifiedLayout BoringWindows l a
 boringAuto = ModifiedLayout (BoringWindows M.empty [] (Just []))
 
 instance LayoutModifier BoringWindows Window where
-    redoLayout (b@BoringWindows { hiddenBoring = bs }) _r mst arrs = do
+    redoLayout b@BoringWindows{ hiddenBoring = bs } _r mst arrs = do
         let bs' = W.integrate' mst \\ map fst arrs
-        return (arrs, Just $ b { hiddenBoring = const bs' <$> bs } )
+        return (arrs, Just $ b { hiddenBoring = bs' <$ bs } )
 
     handleMessOrMaybeModifyIt bst@(BoringWindows nbs cbs lbs) m
         | Just (Replace k ws) <- fromMessage m
-        , maybe True (ws/=) (M.lookup k nbs) =
+        , Just ws /= M.lookup k nbs =
             let nnb = if null ws then M.delete k nbs
                           else M.insert k ws nbs
             in rjl bst { namedBoring = nnb }
@@ -155,8 +155,8 @@ instance LayoutModifier BoringWindows Window where
               skipBoringSwapUp = skipBoring'
                                    (maybe True (`notElem` bs) . listToMaybe . W.down)
                                    swapUp'
-              skipBoring' p f st = fromMaybe st $ listToMaybe
-                                   $ filter p
+              skipBoring' p f st = fromMaybe st
+                                   $ find p
                                    $ drop 1
                                    $ take (length $ W.integrate st)
                                    $ iterate f st

XMonad/Layout/ButtonDecoration.hs

@@ -48,7 +48,7 @@ buttonDeco :: (Eq a, Shrinker s) => s -> Theme
            -> l a -> ModifiedLayout (Decoration ButtonDecoration s) l a
 buttonDeco s c = decoration s c $ NFD True
 
-data ButtonDecoration a = NFD Bool deriving (Show, Read)
+newtype ButtonDecoration a = NFD Bool deriving (Show, Read)
 
 instance Eq a => DecorationStyle ButtonDecoration a where
     describeDeco _ = "ButtonDeco"

XMonad/Layout/CenteredMaster.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Layout.CenteredMaster
@@ -29,6 +29,8 @@ import XMonad
 import XMonad.Layout.LayoutModifier
 import qualified XMonad.StackSet as W
 
+import Control.Arrow (first)
+
 -- $usage
 -- This module defines two new layout modifiers: centerMaster and topRightMaster.
 -- centerMaster places master window at center of screen, on top of others.
@@ -76,15 +78,15 @@ applyPosition :: (LayoutClass l a, Eq a) =>
 
 applyPosition pos wksp rect = do
   let stack = W.stack wksp
-  let ws = W.integrate' $ stack
+  let ws = W.integrate' stack
   if null ws then
      runLayout wksp rect
      else do
-       let first = head ws
+       let firstW = head ws
        let other  = tail ws
-       let filtStack = stack >>= W.filter (first /=)
+       let filtStack = stack >>= W.filter (firstW /=)
        wrs <- runLayout (wksp {W.stack = filtStack}) rect
-       return ((first, place pos other rect) : fst wrs, snd wrs)
+       return $ first ((firstW, place pos other rect) :) wrs
 
 -- | Place master window (it's Rectangle is given), using the given Positioner.
 -- If second argument is empty (that is, there is only one window on workspace),
@@ -107,5 +109,3 @@ center rx ry (Rectangle sx sy sw sh) = Rectangle x y w h
         h = round (fromIntegral sh * ry)
         x = sx + fromIntegral (sw-w) `div` 2
         y = sy + fromIntegral (sh-h) `div` 2
-
-

XMonad/Layout/Circle.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses #-}
 
 -----------------------------------------------------------------------------
 -- |

XMonad/Layout/Column.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Layout.Column
@@ -40,7 +40,7 @@ import qualified XMonad.StackSet as W
 -- In this example, each next window will have height 1.6 times less then
 -- previous window.
 
-data Column a = Column Float deriving (Read,Show)
+newtype Column a = Column Float deriving (Read,Show)
 
 instance LayoutClass Column a where
     pureLayout = columnLayout
@@ -57,15 +57,13 @@ columnLayout (Column q) rect stack = zip ws rects
           n = length ws
           heights = map (xn n rect q) [1..n]
           ys = [fromIntegral $ sum $ take k heights | k <- [0..n-1]]
-          rects = map (mkRect rect) $ zip heights ys
+          rects = zipWith (curry (mkRect rect)) heights ys
 
 mkRect :: Rectangle -> (Dimension,Position) -> Rectangle
 mkRect (Rectangle xs ys ws _) (h,y) = Rectangle xs (ys+fromIntegral y) ws h
 
 xn :: Int -> Rectangle -> Float -> Int -> Dimension
 xn n (Rectangle _ _ _ h) q k = if q==1 then
-                                  h `div` (fromIntegral n)
+                                  h `div` fromIntegral n
                                else
-                                  round ((fromIntegral h)*q^(n-k)*(1-q)/(1-q^n))
-
-
+                                  round (fromIntegral h*q^(n-k)*(1-q)/(1-q^n))

XMonad/Layout/Combo.hs

@@ -23,7 +23,7 @@ module XMonad.Layout.Combo (
                            ) where
 
 import XMonad hiding (focus)
-import XMonad.Prelude (delete, intersect, isJust, (\\))
+import XMonad.Prelude (delete, fromMaybe, intersect, isJust, (\\))
 import XMonad.StackSet ( integrate', Workspace (..), Stack(..) )
 import XMonad.Layout.WindowNavigation ( MoveWindowToWindow(..) )
 import qualified XMonad.StackSet as W ( differentiate )
@@ -76,14 +76,14 @@ combineTwo = C2 [] []
 instance (LayoutClass l (), LayoutClass l1 a, LayoutClass l2 a, Read a, Show a, Eq a, Typeable a)
     => LayoutClass (CombineTwo (l ()) l1 l2) a where
     runLayout (Workspace _ (C2 f w2 super l1 l2) s) rinput = arrange (integrate' s)
-        where arrange [] = do l1' <- maybe l1 id <$> handleMessage l1 (SomeMessage ReleaseResources)
-                              l2' <- maybe l2 id <$> handleMessage l2 (SomeMessage ReleaseResources)
-                              super' <- maybe super id <$>
+        where arrange [] = do l1' <- fromMaybe l1 <$> handleMessage l1 (SomeMessage ReleaseResources)
+                              l2' <- fromMaybe l2 <$> handleMessage l2 (SomeMessage ReleaseResources)
+                              super' <- fromMaybe super <$>
                                         handleMessage super (SomeMessage ReleaseResources)
                               return ([], Just $ C2 [] [] super' l1' l2')
-              arrange [w] = do l1' <- maybe l1 id <$> handleMessage l1 (SomeMessage ReleaseResources)
-                               l2' <- maybe l2 id <$> handleMessage l2 (SomeMessage ReleaseResources)
-                               super' <- maybe super id <$>
+              arrange [w] = do l1' <- fromMaybe l1 <$> handleMessage l1 (SomeMessage ReleaseResources)
+                               l2' <- fromMaybe l2 <$> handleMessage l2 (SomeMessage ReleaseResources)
+                               super' <- fromMaybe super <$>
                                          handleMessage super (SomeMessage ReleaseResources)
                                return ([(w,rinput)], Just $ C2 [w] [w] super' l1' l2')
               arrange origws =
@@ -101,17 +101,17 @@ instance (LayoutClass l (), LayoutClass l1 a, LayoutClass l2 a, Read a, Show a,
                      (wrs1, ml1') <- runLayout (Workspace "" l1 s1) r1
                      (wrs2, ml2') <- runLayout (Workspace "" l2 s2) r2
                      return (wrs1++wrs2, Just $ C2 f' w2'
-                                     (maybe super id msuper') (maybe l1 id ml1') (maybe l2 id ml2'))
+                                     (fromMaybe super msuper') (fromMaybe l1 ml1') (fromMaybe l2 ml2'))
     handleMessage (C2 f ws2 super l1 l2) m
         | Just (MoveWindowToWindow w1 w2) <- fromMessage m,
           w1 `notElem` ws2,
-          w2 `elem` ws2 = do l1' <- maybe l1 id <$> handleMessage l1 m
-                             l2' <- maybe l2 id <$> handleMessage l2 m
+          w2 `elem` ws2 = do l1' <- fromMaybe l1 <$> handleMessage l1 m
+                             l2' <- fromMaybe l2 <$> handleMessage l2 m
                              return $ Just $ C2 f (w1:ws2) super l1' l2'
         | Just (MoveWindowToWindow w1 w2) <- fromMessage m,
           w1 `elem` ws2,
-          w2 `notElem` ws2 = do l1' <- maybe l1 id <$> handleMessage l1 m
-                                l2' <- maybe l2 id <$> handleMessage l2 m
+          w2 `notElem` ws2 = do l1' <- fromMaybe l1 <$> handleMessage l1 m
+                                l2' <- fromMaybe l2 <$> handleMessage l2 m
                                 let ws2' = case delete w1 ws2 of [] -> [w2]
                                                                  x -> x
                                 return $ Just $ C2 f ws2' super l1' l2'
@@ -138,6 +138,6 @@ differentiate [] xs = W.differentiate xs
 broadcastPrivate :: LayoutClass l b => SomeMessage -> [l b] -> X (Maybe [l b])
 broadcastPrivate a ol = do nml <- mapM f ol
                            if any isJust nml
-                              then return $ Just $ zipWith ((flip maybe) id) ol nml
+                              then return $ Just $ zipWith (`maybe` id) ol nml
                               else return Nothing
     where f l = handleMessage l a `catchX` return Nothing

XMonad/Layout/ComboP.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TypeSynonymInstances, DeriveDataTypeable, MultiParamTypeClasses, FlexibleContexts, FlexibleInstances, PatternGuards #-}
+{-# LANGUAGE DeriveDataTypeable, MultiParamTypeClasses, FlexibleContexts, FlexibleInstances, PatternGuards #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Layout.ComboP
@@ -97,7 +97,7 @@ instance (LayoutClass l (), LayoutClass l1 Window, LayoutClass l2 Window) =>
             superstack = Just Stack { focus=(), up=[], down=[()] }
             f' = focus s:delete (focus s) f  -- list of focused windows, contains 2 elements at most
         in do
-            matching <- (hasProperty prop) `filterM` new  -- new windows matching predecate
+            matching <- hasProperty prop `filterM` new  -- new windows matching predecate
             let w1' = w1c ++ matching                     -- updated first pane windows
                 w2' = w2c ++ (new \\ matching)            -- updated second pane windows
                 s1 = differentiate f' w1'                 -- first pane stack
@@ -105,8 +105,8 @@ instance (LayoutClass l (), LayoutClass l1 Window, LayoutClass l2 Window) =>
             ([((),r1),((),r2)], msuper') <- runLayout (Workspace "" super superstack) rinput
             (wrs1, ml1') <- runLayout (Workspace "" l1 s1) r1
             (wrs2, ml2') <- runLayout (Workspace "" l2 s2) r2
-            return  (wrs1++wrs2, Just $ C2P f' w1' w2' (maybe super id msuper')
-                (maybe l1 id ml1') (maybe l2 id ml2') prop)
+            return  (wrs1++wrs2, Just $ C2P f' w1' w2' (fromMaybe super msuper')
+                (fromMaybe l1 ml1') (fromMaybe l2 ml2') prop)
 
     handleMessage us@(C2P f ws1 ws2 super l1 l2 prop) m
         | Just PartitionWins   <- fromMessage m = return . Just $ C2P [] [] [] super l1 l2 prop
@@ -127,13 +127,13 @@ instance (LayoutClass l (), LayoutClass l1 Window, LayoutClass l2 Window) =>
                          msuper' <- handleMessage super m
                          if isJust msuper' || isJust ml1' || isJust ml2'
                             then return $ Just $ C2P f ws1 ws2
-                                                 (maybe super id msuper')
-                                                 (maybe l1 id ml1')
-                                                 (maybe l2 id ml2') prop
+                                                 (fromMaybe super msuper')
+                                                 (fromMaybe l1 ml1')
+                                                 (fromMaybe l2 ml2') prop
                             else return Nothing
 
     description (C2P _ _ _ super l1 l2 prop) = "combining " ++ description l1 ++ " and "++
-                                description l2 ++ " with " ++ description super ++ " using "++ (show prop)
+                                description l2 ++ " with " ++ description super ++ " using "++ show prop
 
 -- send focused window to the other pane. Does nothing if we don't
 -- own the focused window
@@ -164,7 +164,7 @@ forwardToFocused (C2P f ws1 ws2 super l1 l2 prop) m = do
             then return Nothing
             else handleMessage super m
     if isJust ml1 || isJust ml2 || isJust ms
-        then return $ Just $ C2P f ws1 ws2 (maybe super id ms) (maybe l1 id ml1) (maybe l2 id ml2) prop
+        then return $ Just $ C2P f ws1 ws2 (fromMaybe super ms) (fromMaybe l1 ml1) (fromMaybe l2 ml2) prop
         else return Nothing
 
 -- forwards message m to layout l if focused window is among w
@@ -172,7 +172,7 @@ forwardIfFocused :: (LayoutClass l Window) => l Window -> [Window] -> SomeMessag
 forwardIfFocused l w m = do
     mst <- gets (W.stack . W.workspace . W.current . windowset)
     maybe (return Nothing) send mst where
-    send st = if (W.focus st) `elem` w
+    send st = if W.focus st `elem` w
                 then handleMessage l m
                 else return Nothing
 

XMonad/Layout/Cross.hs

@@ -34,7 +34,7 @@ import XMonad.Prelude( msum )
 
 -- apply a factor to a Rectangle Dimension
 (<%>) :: Dimension -> Rational -> Dimension
-d <%> f = floor $ f * (fromIntegral d)
+d <%> f = floor $ f * fromIntegral d
 
 -- | The Cross Layout draws the focused window in the center of the screen
 --   and part of the other windows on the sides. The 'Shrink' and 'Expand'
@@ -57,10 +57,10 @@ simpleCross :: Cross a
 simpleCross = Cross (4/5) (1/100)
 
 instance LayoutClass Cross a where
-    pureLayout (Cross f _) r s = [(focus s, mainRect r f)] ++
-                                 (zip winCycle (upRects r f)) ++
-                                 (zip (reverse winCycle) (downRects r f))
-        where winCycle = (up s) ++ (reverse (down s))
+    pureLayout (Cross f _) r s = [(focus s, mainRect r f)]
+                              ++ zip winCycle (upRects r f)
+                              ++ zip (reverse winCycle) (downRects r f)
+        where winCycle = up s ++ reverse (down s)
 
     pureMessage (Cross f d) m = msum [fmap resize (fromMessage m)]
         where resize Shrink = Cross (max (1/100) $ f - d) d
@@ -71,8 +71,8 @@ instance LayoutClass Cross a where
 -- get the Rectangle for the focused window
 mainRect :: Rectangle -> Rational -> Rectangle
 mainRect (Rectangle rx ry rw rh) f = Rectangle
-                                     (rx + (fromIntegral (rw <%> invf)))
-                                     (ry + (fromIntegral (rh <%> invf)))
+                                     (rx + fromIntegral (rw <%> invf))
+                                     (ry + fromIntegral (rh <%> invf))
                                      (rw <%> f) (rh <%> f)
     where invf = (1/2) * (1-f)
 
@@ -88,25 +88,25 @@ downRects r f = [bottomRectangle r nf, leftRectangle r nf]
 
 topRectangle :: Rectangle -> Rational -> Rectangle
 topRectangle (Rectangle rx ry rw rh) f = Rectangle
-                                         (rx + (fromIntegral (rw <%> ((1-f)*(1/2)))))
+                                         (rx + fromIntegral (rw <%> ((1-f)*(1/2))))
                                          ry
                                          (rw <%> f) (rh <%> ((1-f)*(1/2)))
 
 rightRectangle :: Rectangle -> Rational -> Rectangle
 rightRectangle (Rectangle rx ry rw rh) f = Rectangle
-                                           (rx + (fromIntegral (rw - (rw <%> (1/2)))))
-                                           (ry + (fromIntegral (rh <%> ((1-f)*(1/2)))))
+                                           (rx + fromIntegral (rw - (rw <%> (1/2))))
+                                           (ry + fromIntegral (rh <%> ((1-f)*(1/2))))
                                            (rw <%> (1/2)) (rh <%> f)
 
 bottomRectangle :: Rectangle -> Rational -> Rectangle
 bottomRectangle (Rectangle rx ry rw rh) f = Rectangle
-                                            (rx + (fromIntegral (rw <%> ((1-f)*(1/2)))))
-                                            (ry + (fromIntegral (rh - (rh <%> ((1-f)*(1/2))))))
+                                            (rx + fromIntegral (rw <%> ((1-f)*(1/2))))
+                                            (ry + fromIntegral (rh - (rh <%> ((1-f)*(1/2)))))
                                             (rw <%> f) (rh <%> ((1-f)*(1/2)))
 
 leftRectangle :: Rectangle -> Rational -> Rectangle
 leftRectangle (Rectangle rx ry rw rh) f = Rectangle
                                           rx
-                                           (ry + (fromIntegral (rh <%> ((1-f)*(1/2)))))
+                                           (ry + fromIntegral (rh <%> ((1-f)*(1/2))))
                                            (rw <%> (1/2)) (rh <%> f)