diff options
Diffstat (limited to 'XMonad.hs')
| -rw-r--r-- | XMonad.hs | 38 |
1 files changed, 28 insertions, 10 deletions
@@ -17,6 +17,7 @@ module XMonad ( X, WindowSet, WorkspaceId(..), ScreenId(..), XState(..), XConf(..), Layout(..), + Typeable, Message, SomeMessage(..), fromMessage, runX, io, withDisplay, isRoot, spawn, trace, whenJust ) where @@ -28,7 +29,7 @@ import System.IO import System.Posix.Process (executeFile, forkProcess, getProcessStatus) import System.Exit import Graphics.X11.Xlib -import Data.Dynamic ( Dynamic ) +import Data.Typeable import qualified Data.Map as M @@ -36,10 +37,8 @@ import qualified Data.Map as M -- Just the display, width, height and a window list data XState = XState { workspace :: !WindowSet -- ^ workspace list - , layouts :: !(M.Map WorkspaceId (Layout, [Layout])) - -- ^ mapping of workspaces - -- to descriptions of their layouts - } + , layouts :: !(M.Map WorkspaceId (Layout, [Layout])) } + -- ^ mapping of workspaces to descriptions of their layouts data XConf = XConf { display :: Display -- ^ the X11 display @@ -52,8 +51,7 @@ data XConf = XConf , xineScreens :: ![Rectangle] -- ^ dimensions of each screen , normalBorder :: !Color -- ^ border color of unfocused windows - , focusedBorder :: !Color -- ^ border color of the focused window - } + , focusedBorder :: !Color } -- ^ border color of the focused window type WindowSet = StackSet WorkspaceId ScreenId Window @@ -95,10 +93,30 @@ isRoot w = liftM (w==) (asks theRoot) -- Layout handling -- | The different layout modes --- 'doLayout', a pure function to layout a Window set --- 'modifyLayout', +-- 'doLayout', a pure function to layout a Window set 'modifyLayout', +-- 'modifyLayout' can be considered a branch of an exception handler. +-- data Layout = Layout { doLayout :: Rectangle -> [Window] -> [(Window, Rectangle)] - , modifyLayout :: Dynamic -> Maybe Layout } + , modifyLayout :: SomeMessage -> Maybe Layout } + +-- Based on ideas in /An Extensible Dynamically-Typed Hierarchy of Exceptions/, +-- Simon Marlow, 2006. Use extensible messages to the modifyLayout handler. +-- +-- User-extensible messages must be a member of this class: +-- +class (Typeable a, Show a) => Message a + +-- +-- A wrapped value of some type in the Message class. +-- +data SomeMessage = forall a. Message a => SomeMessage a + +-- +-- And now, unwrap a given, unknown Message type, performing a (dynamic) +-- type check on the result. +-- +fromMessage :: Message m => SomeMessage -> Maybe m +fromMessage (SomeMessage m) = cast m -- --------------------------------------------------------------------- -- Utilities |