clean up names of layout code

Config.hs

@@ -115,22 +115,13 @@ focusedBorderColor = "#ff0000"
 borderWidth :: Dimension
 borderWidth = 1
 
--- |
--- The default Layout, a selector between the layouts listed below in
--- defaultLayouts.
---
-defaultLayout :: Layout Window
-defaultLayout = Layout $ LayoutSelection defaultLayouts
-
--- |
--- The list of selectable layouts
-defaultLayouts :: [Layout Window]
-defaultLayouts = [ Layout tiled
-                 , Layout $ Mirror tiled
-                 , Layout Full
-
-                 -- Extension-provided layouts
-                 ]
+-- | The list of possible layouts. Add your custom layouts to this list.
+layouts :: [Layout Window]
+layouts = [ Layout tiled
+          , Layout $ Mirror tiled
+          , Layout Full
+          -- Add extra layouts you want to use here:
+          ]
   where
      -- default tiling algorithm partitions the screen into two panes
      tiled   = Tall nmaster delta ratio
@@ -145,11 +136,24 @@ defaultLayouts = [ Layout tiled
      delta   = 3%100
 
 -- |
--- A list of layouts which xmonad can deserialize.
-possibleLayouts :: [Layout Window]
-possibleLayouts = [defaultLayout
-                  -- Extension-provided layouts
-                  ] ++ defaultLayouts
+-- The top level layout switcher. By default, we simply switch between
+-- the layouts listed in `layouts', but you may program your own selection
+-- behaviour here. Layout transformers would be hooked in here.
+--
+layoutHook :: Layout Window
+layoutHook = Layout $ Select layouts
+
+-- |
+-- The default Layout, a selector between the layouts listed below in
+-- defaultLayouts.
+--
+-- defaultLayout :: Layout Window
+-- defaultLayout = Layout $ LayoutSelection defaultLayouts
+
+-- | Register with xmonad a list of layouts whose state we can preserve over restarts.
+-- There is typically no need to modify this list, the defaults are fine.
+serialisedLayouts :: [Layout Window]
+serialisedLayouts = layoutHook : layouts
 
 -- |
 -- Perform an arbitrary action on each state change.
@@ -175,7 +179,7 @@ keys = M.fromList $
     , ((modMask .|. shiftMask, xK_c     ), kill) -- %! Close the focused window
 
     , ((modMask,               xK_space ), sendMessage NextLayout) -- %! Rotate through the available layout algorithms
-    , ((modMask .|. shiftMask, xK_space ), setLayout defaultLayout) -- %!  Reset the layouts on the current workspace to default
+    , ((modMask .|. shiftMask, xK_space ), setLayout layoutHook) -- %!  Reset the layouts on the current workspace to default
 
     , ((modMask,               xK_n     ), refresh) -- %! Resize viewed windows to the correct size
 

Config.hs-boot

@@ -3,8 +3,8 @@ import Graphics.X11.Xlib.Types (Dimension)
 import Graphics.X11.Xlib (KeyMask,Window)
 import XMonad
 borderWidth :: Dimension
-logHook     :: X ()
 numlockMask :: KeyMask
 workspaces :: [WorkspaceId]
-possibleLayouts :: [Layout Window]
+logHook     :: X ()
 manageHook :: Window -> String -> String -> String -> X (WindowSet -> WindowSet)
+serialisedLayouts :: [Layout Window]

Main.hs

@@ -50,7 +50,7 @@ main = do
     hSetBuffering stdout NoBuffering
     args <- getArgs
 
-    let initialWinset = new defaultLayout workspaces $ zipWith SD xinesc gaps
+    let initialWinset = new layoutHook workspaces $ zipWith SD xinesc gaps
 
         maybeRead s = case reads s of
                             [(x, "")] -> Just x
@@ -59,8 +59,8 @@ main = do
         winset = fromMaybe initialWinset $ do
                     ("--resume" : s : _) <- return args
                     ws                   <- maybeRead s
-                    return . W.ensureTags defaultLayout workspaces
-                           $ W.mapLayout (fromMaybe defaultLayout . maybeRead) ws
+                    return . W.ensureTags layoutHook workspaces
+                           $ W.mapLayout (fromMaybe layoutHook . maybeRead) ws
 
         gaps = take (length xinesc) $ defaultGaps ++ repeat (0,0,0,0)
 

Operations.hs

@@ -20,7 +20,7 @@ module Operations where
 
 import XMonad
 import qualified StackSet as W
-import {-# SOURCE #-} Config (borderWidth,logHook,manageHook,numlockMask,possibleLayouts)
+import {-# SOURCE #-} Config (borderWidth,logHook,manageHook,numlockMask,serialisedLayouts)
 
 import Data.Maybe
 import Data.List            (nub, (\\), find, partition)
@@ -360,46 +360,49 @@ data ChangeLayout = NextLayout | PrevLayout | JumpToLayout String
 instance Message ChangeLayout
 
 instance ReadableLayout Window where
-    defaults = Layout (LayoutSelection []) :
+    defaults = Layout (Select []) :
                Layout Full : Layout (Tall 1 0.1 0.5) :
                Layout (Mirror $ Tall 1 0.1 0.5) :
-               possibleLayouts
+               serialisedLayouts
 
-data LayoutSelection a = LayoutSelection [Layout a]
-                         deriving ( Show, Read )
+data Select a = Select [Layout a] deriving (Show, Read)
+
+instance ReadableLayout a => LayoutClass Select a where
+    doLayout (Select (l:ls)) r s = do
+        (x,ml') <- doLayout l r s
+        return (x, (\l' -> Select (l':ls)) `fmap` ml')
+
+    doLayout (Select []) r s = do
+        (x,_) <- doLayout Full r s
+        return (x,Nothing)
 
-instance ReadableLayout a => LayoutClass LayoutSelection a where
-    doLayout (LayoutSelection (l:ls)) r s =
-        do (x,ml') <- doLayout l r s
-           return (x, (\l' -> LayoutSelection (l':ls)) `fmap` ml')
-    doLayout (LayoutSelection []) r s = do (x,_) <- doLayout Full r s
-                                           return (x,Nothing)
     -- respond to messages only when there's an actual choice:
-    handleMessage (LayoutSelection (l:ls@(_:_))) m
+    handleMessage (Select (l:ls@(_:_))) m
         | Just NextLayout <- fromMessage m = switchl rls
         | Just PrevLayout <- fromMessage m = switchl rls'
         | Just (JumpToLayout x) <- fromMessage m = switchl (j x)
         | Just ReleaseResources <- fromMessage m =
               do mlls' <- mapM (\ll -> handleMessage ll m) (l:ls)
                  let lls' = zipWith (\x mx -> maybe x id mx) (l:ls) mlls'
-                 return $ Just $ LayoutSelection lls'
+                 return $ Just $ Select lls'
         where rls (x:xs) = xs ++ [x]
               rls [] = []
               rls' = reverse . rls . reverse
-              j s zs = case partition (\z -> s == description z) zs of
-                         (xs,ys) -> xs++ys
-              switchl f = do ml' <- handleMessage l (SomeMessage Hide)
-                             return $ Just (LayoutSelection $ f $ fromMaybe l ml':ls)
-    -- otherwise, or if we don't understand the message, pass it along to the real
-    -- layout:
-    handleMessage (LayoutSelection (l:ls)) m
-        =  do ml' <- handleMessage l m
-              return $ (\l' -> LayoutSelection (l':ls)) `fmap` ml'
-    -- Unless there is no layout...
-    handleMessage (LayoutSelection []) _ = return Nothing
+              j s zs = case partition ((s ==) . description) zs of (xs,ys) -> xs++ys
 
-    description (LayoutSelection (x:_)) = description x
-    description _                       = "default"
+              switchl f = do ml' <- handleMessage l (SomeMessage Hide)
+                             return $ Just (Select $ f $ fromMaybe l ml':ls)
+
+    -- otherwise, or if we don't understand the message, pass it along to the real layout:
+    handleMessage (Select (l:ls)) m = do
+            ml' <- handleMessage l m
+            return $ (\l' -> Select (l':ls)) `fmap` ml'
+
+    -- Unless there is no layout...
+    handleMessage (Select []) _ = return Nothing
+
+    description (Select (x:_)) = description x
+    description _              = "default"
 --
 -- Builtin layout algorithms:
 --