diff options
| -rw-r--r-- | XMonad.hs | 15 |
1 files changed, 7 insertions, 8 deletions
@@ -28,6 +28,7 @@ import Prelude hiding ( catch ) import Control.Exception (catch, throw, Exception(ExitException)) import Control.Monad.State import Control.Monad.Reader +import Control.Arrow (first) import System.IO import System.Posix.Process (executeFile, forkProcess, getProcessStatus, createSession) import System.Exit @@ -128,25 +129,23 @@ atom_WM_DELETE_WINDOW = getAtom "WM_DELETE_WINDOW" atom_WM_STATE = getAtom "WM_STATE" ------------------------------------------------------------------------ --- | LayoutClass handling +-- | LayoutClass handling. See particular instances in Operations.hs --- | And existential class that can hold any object that is in --- the LayoutClass. +-- | An existential type that can hold any object that is in the LayoutClass. data Layout a = forall l. LayoutClass l a => Layout (l a) -- | This class defines a set of layout types (held in Layout --- objects) that are used when trying to read an existential --- Layout. +-- objects) that are used when trying to read an existentially wrapped Layout. class ReadableLayout a where defaults :: [Layout a] -- | The different layout modes +-- -- 'doLayout': given a Rectangle and a Stack, layout the stack elements -- inside the given Rectangle. If an element is not given a Rectangle -- by 'doLayout', then it is not shown on screen. Windows are restacked -- according to the order they are returned by 'doLayout'. -- - class (Show (layout a), Read (layout a)) => LayoutClass layout a where -- | Given a Rectangle in which to place the windows, and a Stack of @@ -185,12 +184,12 @@ instance ReadableLayout a => Read (Layout a) where readsPrec _ s = take 1 $ concatMap rl defaults -- We take the first parse only, because multiple matches -- indicate a bad parse. - where rl (Layout x) = map (\(l,s') -> (Layout l,s')) $ rl' x + where rl (Layout x) = map (first Layout) $ rl' x rl' :: LayoutClass l a => l a -> [(l a,String)] rl' _ = reads s instance ReadableLayout a => LayoutClass Layout a where - doLayout (Layout l) r s = fmap (fmap $ fmap Layout) $ doLayout l r s + doLayout (Layout l) r s = fmap (fmap Layout) `liftM` doLayout l r s handleMessage (Layout l) = fmap (fmap Layout) . handleMessage l description (Layout l) = description l |