Bump XMonadContrib version

This makes userCode catch errors even when the
user does something like (return undefined).

Config.hs

@@ -4,147 +4,256 @@
 -- Copyright   :  (c) Spencer Janssen 2007
 -- License     :  BSD3-style (see LICENSE)
 --
--- Maintainer  :  dons@cse.unsw.edu.au
+-- Maintainer  :  dons@galois.com
 -- Stability   :  stable
 -- Portability :  portable
 --
------------------------------------------------------------------------------
+-- This module specifies configurable defaults for xmonad. If you change
+-- values here, be sure to recompile and restart (mod-q) xmonad,
+-- for the changes to take effect.
+--
+------------------------------------------------------------------------
 
 module Config where
 
 --
--- xmonad bindings follow mostly the dwm/wmii conventions:
+-- Useful imports
 --
---     key combination         action
---     
---     mod-shift-return        new xterm
---     mod-p                   launch dmenu
---     mod-shift-p             launch gmrun
--- 
---     mod-space               switch tiling mode
--- 
---     mod-tab                 raise next window in stack
---     mod-j
---     mod-k
--- 
---     mod-h                   decrease the size of the master area
---     mod-l                   increase the size of the master area
--- 
---     mod-shift-c             kill client
---     mod-shift-q             exit window manager
---     mod-shift-ctrl-q        restart window manager ('xmonad' must be in $PATH)
--- 
---     mod-return              cycle the current tiling order
--- 
---     mod-1..9                switch to workspace N
---     mod-shift-1..9          move client to workspace N
--- 
---     mod-w,e,r               switch to physical/Xinerama screen 1, 2 or 3.
--- 
--- xmonad places each window into a "workspace." Each workspace can have
--- any number of windows, which you can cycle though with mod-j and mod-k.
--- Windows are either displayed full screen, tiled horizontally, or tiled
--- vertically. You can toggle the layout mode with mod-space, which will
--- cycle through the available modes.
--- 
--- You can switch to workspace N with mod-N. For example, to switch to
--- workspace 5, you would press mod-5. Similarly, you can move the current
--- window to another workspace with mod-shift-N.
--- 
--- When running with multiple monitors (Xinerama), each screen has exactly
--- 1 workspace visible. When xmonad starts, workspace 1 is on screen 1,
--- workspace 2 is on screen 2, etc. If you switch to a workspace which is
--- currently visible on another screen, xmonad simply switches focus to
--- that screen. If you switch to a workspace which is *not* visible, xmonad
--- replaces the workspace on the *current* screen with the workspace you
--- selected.
--- 
--- For example, if you have the following configuration:
--- 
--- Screen 1: Workspace 2
--- Screen 2: Workspace 5 (current workspace)
--- 
--- and you wanted to view workspace 7 on screen 1, you would press:
--- 
--- mod-2 (to select workspace 2, and make screen 1 the current screen)
--- mod-7 (to select workspace 7)
--- 
--- Since switching to the workspace currently visible on a given screen is
--- such a common operation, shortcuts are provided: mod-{w,e,r} switch to
--- the workspace currently visible on screens 1, 2, and 3 respectively.
--- Likewise, shift-mod-{w,e,r} moves the current window to the workspace on
--- that screen.  Using these keys, the above example would become mod-w
--- mod-7.
--- 
-
+import XMonad
+import Operations
+import qualified StackSet as W
 import Data.Ratio
-import Data.Bits
+import Data.Bits ((.|.))
 import qualified Data.Map as M
 import System.Exit
 import Graphics.X11.Xlib
-import XMonad
-import Operations
 
--- The number of workspaces:
-workspaces :: Int
-workspaces = 9
+-- % Extension-provided imports
 
--- modMask lets you easily change which modkey you use. The default is mod1Mask
--- ("left alt").  You may also consider using mod3Mask ("right alt"), which
--- does not conflict with emacs keybindings. The "windows key" is usually
--- mod4Mask.
+-- | The default number of workspaces (virtual screens) and their names.
+-- By default we use numeric strings, but any string may be used as a
+-- workspace name. The number of workspaces is determined by the length
+-- of this list.
+--
+-- A tagging example:
+--
+-- > workspaces = ["web", "irc", "code" ] ++ map show [4..9]
+--
+workspaces :: [WorkspaceId]
+workspaces = map show [1 .. 9 :: Int]
+
+-- | modMask lets you specify which modkey you want to use. The default
+-- is mod1Mask ("left alt").  You may also consider using mod3Mask
+-- ("right alt"), which does not conflict with emacs keybindings. The
+-- "windows key" is usually mod4Mask.
+--
 modMask :: KeyMask
 modMask = mod1Mask
 
--- How much to change the horizontal/vertical split bar by defalut.
-defaultDelta :: Rational
-defaultDelta = 3%100
-
--- The mask for the numlock key. You may need to change this on some systems.
+-- | The mask for the numlock key. Numlock status is "masked" from the
+-- current modifier status, so the keybindings will work with numlock on or
+-- off. You may need to change this on some systems.
+--
+-- You can find the numlock modifier by running "xmodmap" and looking for a
+-- modifier with Num_Lock bound to it:
+--
+-- > $ xmodmap | grep Num
+-- > mod2        Num_Lock (0x4d)
+--
+-- Set numlockMask = 0 if you don't have a numlock key, or want to treat
+-- numlock status separately.
+--
 numlockMask :: KeyMask
-numlockMask = lockMask
+numlockMask = mod2Mask
 
--- What layout to start in, and what the default proportion for the
--- left pane should be in the tiled layout.  See LayoutDesc and
--- friends in XMonad.hs for options.
-startingLayoutDesc :: LayoutDesc
-startingLayoutDesc =
-    LayoutDesc { layoutType   = Full
-               , tileFraction = 1%2  }
+-- | Width of the window border in pixels.
+--
+borderWidth :: Dimension
+borderWidth = 1
 
--- The keys list.
+-- | Border colors for unfocused and focused windows, respectively.
+--
+normalBorderColor, focusedBorderColor :: String
+normalBorderColor  = "#dddddd"
+focusedBorderColor = "#ff0000"
+
+-- | Default offset of drawable screen boundaries from each physical
+-- screen. Anything non-zero here will leave a gap of that many pixels
+-- on the given edge, on the that screen. A useful gap at top of screen
+-- for a menu bar (e.g. 15)
+--
+-- An example, to set a top gap on monitor 1, and a gap on the bottom of
+-- monitor 2, you'd use a list of geometries like so:
+--
+-- > defaultGaps = [(18,0,0,0),(0,18,0,0)] -- 2 gaps on 2 monitors
+--
+-- Fields are: top, bottom, left, right.
+--
+defaultGaps :: [(Int,Int,Int,Int)]
+defaultGaps = [(0,0,0,0)] -- 15 for default dzen font
+
+------------------------------------------------------------------------
+-- Window rules
+
+-- | Execute arbitrary actions and WindowSet manipulations when managing
+-- a new window. You can use this to, for example, always float a
+-- particular program, or have a client always appear on a particular
+-- workspace.
+--
+manageHook :: Window -- ^ the new window to manage
+           -> String -- ^ window title
+           -> String -- ^ window resource name
+           -> String -- ^ window resource class
+           -> X (WindowSet -> WindowSet)
+
+-- Always float various programs:
+manageHook w _ _ c | c `elem` floats = fmap (W.float w . snd) (floatLocation w)
+ where floats = ["MPlayer", "Gimp"]
+
+-- Desktop panels and dock apps should be ignored by xmonad:
+manageHook w _ n _ | n `elem` ignore = reveal w >> return (W.delete w)
+ where ignore = ["gnome-panel", "desktop_window", "kicker", "kdesktop"]
+
+-- Automatically send Firefox windows to the "web" workspace:
+-- If a workspace named "web" doesn't exist, the window will appear on the
+-- current workspace.
+manageHook _ _ "Gecko" _ = return $ W.shift "web"
+
+-- The default rule: return the WindowSet unmodified.  You typically do not
+-- want to modify this line.
+manageHook _ _ _ _ = return id
+
+------------------------------------------------------------------------
+-- Extensible 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:
+          -- % Extension-provided layouts
+          ]
+  where
+     -- default tiling algorithm partitions the screen into two panes
+     tiled   = Tall nmaster delta ratio
+
+     -- The default number of windows in the master pane
+     nmaster = 1
+
+     -- Default proportion of screen occupied by master pane
+     ratio   = 1%2
+
+     -- Percent of screen to increment by when resizing panes
+     delta   = 3%100
+
+-- | The top level layout switcher. Most users will not need to modify this binding.
+--
+-- By default, we simply switch between the layouts listed in `layouts'
+-- above, but you may program your own selection behaviour here. Layout
+-- transformers, for example, would be hooked in here.
+--
+layoutHook :: Layout Window
+layoutHook = Layout $ Select layouts
+
+-- | 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
+
+------------------------------------------------------------------------
+-- Logging
+
+-- | Perform an arbitrary action on each internal state change or X event.
+-- Examples include:
+--      * do nothing
+--      * log the state to stdout
+--
+-- See the 'DynamicLog' extension for examples.
+--
+logHook :: X ()
+logHook = return ()
+
+------------------------------------------------------------------------
+-- Key bindings:
+
+-- | The xmonad key bindings. Add, modify or remove key bindings here.
+--
+-- (The comment formatting character is used when generating the manpage)
+--
 keys :: M.Map (KeyMask, KeySym) (X ())
 keys = M.fromList $
-    [ ((modMask .|. shiftMask, xK_Return), spawn "xterm")
-    , ((modMask,               xK_p     ), spawn "exe=`dmenu_path | dmenu` && exec $exe")
-    , ((modMask .|. shiftMask, xK_p     ), spawn "gmrun")
-    , ((modMask,               xK_space ), switchLayout)
+    -- launching and killing programs
+    [ ((modMask .|. shiftMask, xK_Return), spawn "xterm") -- %! Launch an xterm
+    , ((modMask,               xK_p     ), spawn "exe=`dmenu_path | dmenu` && eval \"exec $exe\"") -- %! Launch dmenu
+    , ((modMask .|. shiftMask, xK_p     ), spawn "gmrun") -- %! Launch gmrun
+    , ((modMask .|. shiftMask, xK_c     ), kill) -- %! Close the focused window
 
-    , ((modMask,               xK_Tab   ), raise GT)
-    , ((modMask,               xK_j     ), raise GT)
-    , ((modMask,               xK_k     ), raise LT)
+    , ((modMask,               xK_space ), sendMessage NextLayout) -- %! Rotate through the available layout algorithms
+    , ((modMask .|. shiftMask, xK_space ), setLayout layoutHook) -- %!  Reset the layouts on the current workspace to default
 
-    , ((modMask,               xK_h     ), changeSplit (negate defaultDelta))
-    , ((modMask,               xK_l     ), changeSplit defaultDelta)
+    , ((modMask,               xK_n     ), refresh) -- %! Resize viewed windows to the correct size
 
-    , ((modMask .|. shiftMask, xK_c     ), kill)
+    -- move focus up or down the window stack
+    , ((modMask,               xK_Tab   ), windows W.focusDown) -- %! Move focus to the next window
+    , ((modMask,               xK_j     ), windows W.focusDown) -- %! Move focus to the next window
+    , ((modMask,               xK_k     ), windows W.focusUp  ) -- %! Move focus to the previous window
+    , ((modMask,               xK_m     ), windows W.focusMaster  ) -- %! Move focus to the master window
 
-    , ((modMask .|. shiftMask, xK_q                     ), io $ exitWith ExitSuccess)
-    , ((modMask .|. shiftMask .|. controlMask, xK_q     ), io restart)
+    -- modifying the window order
+    , ((modMask,               xK_Return), windows W.swapMaster) -- %! Swap the focused window and the master window
+    , ((modMask .|. shiftMask, xK_j     ), windows W.swapDown  ) -- %! Swap the focused window with the next window
+    , ((modMask .|. shiftMask, xK_k     ), windows W.swapUp    ) -- %! Swap the focused window with the previous window
 
-    -- Cycle the current tiling order
-    , ((modMask,               xK_Return), promote)
+    -- resizing the master/slave ratio
+    , ((modMask,               xK_h     ), sendMessage Shrink) -- %! Shrink the master area
+    , ((modMask,               xK_l     ), sendMessage Expand) -- %! Expand the master area
 
-    ] ++
-    -- Keybindings to get to each workspace:
-    [((m .|. modMask, xK_0 + fromIntegral i), f (fromIntegral (pred i))) -- index from 0.
-        | i <- [1 .. workspaces]
-        , (f, m) <- [(view, 0), (tag, shiftMask)]]
+    -- floating layer support
+    , ((modMask,               xK_t     ), withFocused $ windows . W.sink) -- %! Push window back into tiling
 
-    -- Keybindings to each screen :
-    -- mod-wer (underneath 123) switches to physical/Xinerama screens 1 2 and 3
+    -- 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
+
+    -- toggle the status bar gap
+    , ((modMask              , xK_b     ), modifyGap (\i n -> let x = (defaultGaps ++ repeat (0,0,0,0)) !! i in if n == x then (0,0,0,0) else x)) -- %! Toggle the status bar gap
+
+    -- quit, or restart
+    , ((modMask .|. shiftMask, xK_q     ), io (exitWith ExitSuccess)) -- %! Quit xmonad
+    , ((modMask              , xK_q     ), broadcastMessage ReleaseResources >> restart Nothing True) -- %! Restart xmonad
+
+    -- % Extension-provided key bindings
+    ]
     ++
-    [((m .|. modMask, key), screenWorkspace sc >>= f)
+    -- mod-[1..9] %! Switch to workspace N
+    -- mod-shift-[1..9] %! Move client to workspace N
+    [((m .|. modMask, k), windows $ f i)
+        | (i, k) <- zip workspaces [xK_1 ..]
+        , (f, m) <- [(W.greedyView, 0), (W.shift, shiftMask)]]
+    ++
+    -- mod-{w,e,r} %! Switch to physical/Xinerama screens 1, 2, or 3
+    -- mod-shift-{w,e,r} %! Move client to screen 1, 2, or 3
+    [((m .|. modMask, key), screenWorkspace sc >>= flip whenJust (windows . f))
         | (key, sc) <- zip [xK_w, xK_e, xK_r] [0..]
-        , (f, m) <- [(view, 0), (tag, shiftMask)]]
+        , (f, m) <- [(W.view, 0), (W.shift, shiftMask)]]
 
+    -- % Extension-provided key bindings lists
+
+-- | Mouse bindings: default actions bound to mouse events
+--
+mouseBindings :: M.Map (KeyMask, Button) (Window -> X ())
+mouseBindings = M.fromList $
+    -- mod-button1 %! Set the window to floating mode and move by dragging
+    [ ((modMask, button1), (\w -> focus w >> mouseMoveWindow w))
+    -- mod-button2 %! Raise the window to the top of the stack
+    , ((modMask, button2), (\w -> focus w >> windows W.swapMaster))
+    -- mod-button3 %! Set the window to floating mode and resize by dragging
+    , ((modMask, button3), (\w -> focus w >> mouseResizeWindow w))
+    -- you may also bind events to the mouse scroll wheel (button4 and button5)
+
+    -- % Extension-provided mouse bindings
+    ]
+
+-- % Extension-provided definitions

Config.hs-boot

@@ -0,0 +1,10 @@
+module Config where
+import Graphics.X11.Xlib.Types (Dimension)
+import Graphics.X11.Xlib (KeyMask,Window)
+import XMonad
+borderWidth :: Dimension
+numlockMask :: KeyMask
+workspaces :: [WorkspaceId]
+logHook     :: X ()
+manageHook :: Window -> String -> String -> String -> X (WindowSet -> WindowSet)
+serialisedLayouts :: [Layout Window]

LICENSE

@@ -14,7 +14,7 @@ are met:
    may be used to endorse or promote products derived from this software
    without specific prior written permission.
 
-THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE

Main.hs

@@ -1,4 +1,4 @@
------------------------------------------------------------------------------
+----------------------------------------------------------------------------
 -- |
 -- Module      :  Main.hs
 -- Copyright   :  (c) Spencer Janssen 2007
@@ -8,100 +8,149 @@
 -- Stability   :  unstable
 -- Portability :  not portable, uses mtl, X11, posix
 --
+-- xmonad, a minimalist, tiling window manager for X11
+--
 -----------------------------------------------------------------------------
---
--- xmonad, a minimal window manager for X11
---
+
+module Main where
 
 import Data.Bits
 import qualified Data.Map as M
+import qualified Data.Set as S
+import Control.Monad.Reader
+import Control.Monad.State
+import Data.Maybe (fromMaybe)
+
+import System.Environment (getArgs)
 
 import Graphics.X11.Xlib hiding (refreshKeyboardMapping)
 import Graphics.X11.Xlib.Extras
-import Graphics.X11.Xinerama
-
-import Control.Monad.State
-
-import qualified StackSet as W
+import Graphics.X11.Xinerama    (getScreenInfo)
 
 import XMonad
-import Operations
 import Config
+import StackSet (new, floating, member)
+import qualified StackSet as W
+import Operations
 
---
+import System.IO
+
+-- |
 -- The main entry point
 --
 main :: IO ()
 main = do
     dpy   <- openDisplay ""
     let dflt = defaultScreen dpy
+
     rootw  <- rootWindow dpy dflt
-    wmdelt <- internAtom dpy "WM_DELETE_WINDOW" False
-    wmprot <- internAtom dpy "WM_PROTOCOLS"     False
     xinesc <- getScreenInfo dpy
+    nbc    <- initColor dpy normalBorderColor
+    fbc    <- initColor dpy focusedBorderColor
+    hSetBuffering stdout NoBuffering
+    args <- getArgs
 
-    let st = XState
+    let initialWinset = new layoutHook workspaces $ zipWith SD xinesc gaps
+
+        maybeRead s = case reads s of
+                            [(x, "")] -> Just x
+                            _         -> Nothing
+
+        winset = fromMaybe initialWinset $ do
+                    ("--resume" : s : _) <- return args
+                    ws                   <- maybeRead s
+                    return . W.ensureTags layoutHook workspaces
+                           $ W.mapLayout (fromMaybe layoutHook . maybeRead) ws
+
+        gaps = take (length xinesc) $ defaultGaps ++ repeat (0,0,0,0)
+
+        cf = XConf
             { display       = dpy
-            , xineScreens   = xinesc
             , theRoot       = rootw
-            , wmdelete      = wmdelt
-            , wmprotocols   = wmprot
-            -- fromIntegral needed for X11 versions that use Int instead of CInt.
-            , dimensions    = (fromIntegral (displayWidth dpy dflt),
-                               fromIntegral (displayHeight dpy dflt))
-            , workspace     = W.empty workspaces (length xinesc)
-            , defaultLayoutDesc = startingLayoutDesc
-            , layoutDescs   = M.empty
-            }
+            , normalBorder  = nbc
+            , focusedBorder = fbc }
+        st = XState
+            { windowset     = initialWinset
+            , mapped        = S.empty
+            , waitingUnmap  = M.empty
+            , dragging      = Nothing }
 
-    xSetErrorHandler -- in C, I'm too lazy to write the binding
+    xSetErrorHandler -- in C, I'm too lazy to write the binding: dons
 
     -- setup initial X environment
     sync dpy False
-    selectInput dpy rootw $  substructureRedirectMask
-                         .|. substructureNotifyMask
-                         .|. enterWindowMask
-                         .|. leaveWindowMask
-    grabKeys dpy rootw
-    sync dpy False
+    selectInput dpy rootw $  substructureRedirectMask .|. substructureNotifyMask
+                         .|. enterWindowMask .|. leaveWindowMask .|. structureNotifyMask
 
-    ws <- scan dpy rootw
     allocaXEvent $ \e ->
-        runX st $ do
+        runX cf st $ do
+
+            grabKeys
+            grabButtons
+
+            io $ sync dpy False
+
+            -- bootstrap the windowset, Operations.windows will identify all
+            -- the windows in winset as new and set initial properties for
+            -- those windows
+            windows (const winset)
+
+            -- scan for all top-level windows, add the unmanaged ones to the
+            -- windowset
+            ws <- io $ scan dpy rootw
             mapM_ manage ws
-            forever $ handle =<< xevent dpy e
-      where
-        xevent d e = io (nextEvent d e >> getEvent e)
-        forever a = a >> forever a
+
+            -- main loop, for all you HOF/recursion fans out there.
+            forever_ $ handle =<< io (nextEvent dpy e >> getEvent e)
+
+    return ()
+      where forever_ a = a >> forever_ a
 
 -- ---------------------------------------------------------------------
 -- IO stuff. Doesn't require any X state
 -- Most of these things run only on startup (bar grabkeys)
 
--- | scan for any initial windows to manage
+-- | scan for any new windows to manage. If they're already managed,
+-- this should be idempotent.
 scan :: Display -> Window -> IO [Window]
 scan dpy rootw = do
     (_, _, ws) <- queryTree dpy rootw
     filterM ok ws
-  where
-    ok w = do wa <- getWindowAttributes dpy w
+  -- TODO: scan for windows that are either 'IsViewable' or where WM_STATE ==
+  -- Iconic
+  where ok w = do wa <- getWindowAttributes dpy w
+                  a  <- internAtom dpy "WM_STATE" False
+                  p  <- getWindowProperty32 dpy a w
+                  let ic = case p of
+                            Just (3:_) -> True -- 3 for iconified
+                            _          -> False
                   return $ not (wa_override_redirect wa)
-                     && wa_map_state wa == waIsViewable
+                         && (wa_map_state wa == waIsViewable || ic)
 
 -- | Grab the keys back
-grabKeys :: Display -> Window -> IO ()
-grabKeys dpy rootw = do
-    ungrabKey dpy '\0' {-AnyKey-} anyModifier rootw
-    flip mapM_ (M.keys keys) $ \(mask,sym) -> do
-         kc <- keysymToKeycode dpy sym
-         mapM_ (grab kc) [mask, mask .|. numlockMask] -- note: no numlock
-  where
-    grab kc m = grabKey dpy kc m rootw True grabModeAsync grabModeAsync
+grabKeys :: X ()
+grabKeys = do
+    XConf { display = dpy, theRoot = rootw } <- ask
+    let grab kc m = io $ grabKey dpy kc m rootw True grabModeAsync grabModeAsync
+    io $ ungrabKey dpy anyKey anyModifier rootw
+    forM_ (M.keys keys) $ \(mask,sym) -> do
+         kc <- io $ keysymToKeycode dpy sym
+         -- "If the specified KeySym is not defined for any KeyCode,
+         -- XKeysymToKeycode() returns zero."
+         when (kc /= '\0') $ mapM_ (grab kc . (mask .|.)) extraModifiers
+
+-- | XXX comment me
+grabButtons :: X ()
+grabButtons = do
+    XConf { display = dpy, theRoot = rootw } <- ask
+    let grab button mask = io $ grabButton dpy button mask rootw False buttonPressMask
+                                           grabModeAsync grabModeSync none none
+    io $ ungrabButton dpy anyButton anyModifier rootw
+    mapM_ (\(m,b) -> mapM_ (grab b . (m .|.)) extraModifiers) (M.keys mouseBindings)
 
 -- ---------------------------------------------------------------------
--- Event handler
---
--- | handle. Handle X events
+-- | Event handler. Map X events onto calls into Operations.hs, which
+-- modify our internal model of the window manager state.
 --
 -- Events dwm handles that we don't:
 --
@@ -109,81 +158,105 @@ grabKeys dpy rootw = do
 --    [Expose]         = expose,
 --    [PropertyNotify] = propertynotify,
 --
--- Todo: seperate IO from X monad stuff. We want to be able to test the
--- handler, and client functions, with dummy X interface ops, in QuickCheck
---
--- Will require an abstract interpreter from Event -> X Action, which
--- modifies the internal X state, and then produces an IO action to
--- evaluate.
---
--- XCreateWindowEvent(3X11)
--- Window manager clients normally should ignore this window if the
--- override_redirect member is True.
---
 
 handle :: Event -> X ()
 
 -- run window manager command
 handle (KeyEvent {ev_event_type = t, ev_state = m, ev_keycode = code})
-    | t == keyPress
-    = withDisplay $ \dpy -> do
+    | t == keyPress = withDisplay $ \dpy -> do
         s  <- io $ keycodeToKeysym dpy code 0
-        whenJust (M.lookup (m,s) keys) id
+        userCode $ whenJust (M.lookup (cleanMask m,s) keys) id
 
 -- manage a new window
 handle (MapRequestEvent    {ev_window = w}) = withDisplay $ \dpy -> do
     wa <- io $ getWindowAttributes dpy w -- ignore override windows
-    when (not (wa_override_redirect wa)) $ manage w
+    -- need to ignore mapping requests by managed windows not on the current workspace
+    managed <- isClient w
+    when (not (wa_override_redirect wa) && not managed) $ do manage w
 
 -- window destroyed, unmanage it
-handle (DestroyWindowEvent {ev_window = w}) = do b <- isClient w; when b $ unmanage w
-
 -- window gone,      unmanage it
-handle (UnmapEvent         {ev_window = w}) = do b <- isClient w; when b $ unmanage w
+handle (DestroyWindowEvent {ev_window = w}) = whenX (isClient w) $ unmanage w
+
+-- We track expected unmap events in waitingUnmap.  We ignore this event unless
+-- it is synthetic or we are not expecting an unmap notification from a window.
+handle (UnmapEvent {ev_window = w, ev_send_event = synthetic}) = whenX (isClient w) $ do
+    e <- gets (fromMaybe 0 . M.lookup w . waitingUnmap)
+    if (synthetic || e == 0)
+        then unmanage w
+        else modify (\s -> s { waitingUnmap = M.adjust pred w (waitingUnmap s) })
 
 -- set keyboard mapping
-handle e@(MappingNotifyEvent {ev_window = w}) = do
-    -- this fromIntegral is only necessary with the old X11 version that uses
-    -- Int instead of CInt.  TODO delete it when there is a new release of X11
-    let m = (ev_request e, ev_first_keycode e, fromIntegral $ ev_count e)
-    withDisplay $ \d -> io $ refreshKeyboardMapping d m
-    when (ev_request e == mappingKeyboard) $ withDisplay $ io . flip grabKeys w
+handle e@(MappingNotifyEvent {}) = do
+    io $ refreshKeyboardMapping e
+    when (ev_request e == mappingKeyboard) grabKeys
 
--- click on an unfocussed window
-handle (ButtonEvent {ev_window = w, ev_event_type = t})
-    | t == buttonPress
-    = safeFocus w
+-- handle button release, which may finish dragging.
+handle e@(ButtonEvent {ev_event_type = t})
+    | t == buttonRelease = do
+    drag <- gets dragging
+    case drag of
+        -- we're done dragging and have released the mouse:
+        Just (_,f) -> modify (\s -> s { dragging = Nothing }) >> f
+        Nothing    -> broadcastMessage e
 
--- entered a normal window
+-- handle motionNotify event, which may mean we are dragging.
+handle e@(MotionEvent {ev_event_type = _t, ev_x = x, ev_y = y}) = do
+    drag <- gets dragging
+    case drag of
+        Just (d,_) -> d (fromIntegral x) (fromIntegral y) -- we're dragging
+        Nothing -> broadcastMessage e
+
+-- click on an unfocused window, makes it focused on this workspace
+handle e@(ButtonEvent {ev_window = w,ev_event_type = t,ev_button = b })
+    | t == buttonPress = do
+    -- If it's the root window, then it's something we
+    -- grabbed in grabButtons. Otherwise, it's click-to-focus.
+    isr <- isRoot w
+    if isr then userCode $ whenJust (M.lookup (cleanMask (ev_state e), b) mouseBindings) ($ ev_subwindow e)
+           else focus w
+    sendMessage e -- Always send button events.
+
+-- entered a normal window, makes this focused.
 handle e@(CrossingEvent {ev_window = w, ev_event_type = t})
-    | t == enterNotify  && ev_mode e == notifyNormal && ev_detail e /= notifyInferior
-    = safeFocus w
+    | t == enterNotify && ev_mode   e == notifyNormal
+                       && ev_detail e /= notifyInferior = focus w
 
 -- left a window, check if we need to focus root
 handle e@(CrossingEvent {ev_event_type = t})
     | t == leaveNotify
-    = do rootw <- gets theRoot
-         when (ev_window e == rootw && not (ev_same_screen e)) $ setFocus rootw
+    = do rootw <- asks theRoot
+         when (ev_window e == rootw && not (ev_same_screen e)) $ setFocusX rootw
 
 -- configure a window
-handle e@(ConfigureRequestEvent {ev_window = w}) = do
-    XState { display = dpy, workspace = ws } <- get
+handle e@(ConfigureRequestEvent {ev_window = w}) = withDisplay $ \dpy -> do
+    ws <- gets windowset
+    wa <- io $ getWindowAttributes dpy w
 
-    when (W.member w ws) $ -- already managed, reconfigure (see client:configure()
-        trace ("Reconfigure already managed window: " ++ show w)
-
-    io $ configureWindow dpy (ev_window e) (ev_value_mask e) $ WindowChanges
+    if M.member w (floating ws)
+        || not (member w ws)
+        then do io $ configureWindow dpy w (ev_value_mask e) $ WindowChanges
                     { wc_x            = ev_x e
                     , wc_y            = ev_y e
                     , wc_width        = ev_width e
                     , wc_height       = ev_height e
-        , wc_border_width = ev_border_width e
+                    , wc_border_width = fromIntegral borderWidth
                     , wc_sibling      = ev_above e
-        -- this fromIntegral is only necessary with the old X11 version that uses
-        -- Int instead of CInt.  TODO delete it when there is a new release of X11
-        , wc_stack_mode   = fromIntegral $ ev_detail e
-        }
-
+                    , wc_stack_mode   = ev_detail e }
+                when (member w ws) (float w)
+        else io $ allocaXEvent $ \ev -> do
+                 setEventType ev configureNotify
+                 setConfigureEvent ev w w
+                     (wa_x wa) (wa_y wa) (wa_width wa)
+                     (wa_height wa) (ev_border_width e) none (wa_override_redirect wa)
+                 sendEvent dpy w False 0 ev
     io $ sync dpy False
 
-handle e = trace (eventName e) -- ignoring
+-- configuration changes in the root may mean display settings have changed
+handle (ConfigureEvent {ev_window = w}) = whenX (isRoot w) rescreen
+
+-- property notify
+handle PropertyEvent { ev_event_type = t, ev_atom = a }
+    | t == propertyNotify && a == wM_NAME = userCode logHook
+
+handle e = broadcastMessage e -- trace (eventName e) -- ignoring

Operations.hs

@@ -1,282 +1,656 @@
------------------------------------------------------------------------------
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+{-# OPTIONS_GHC -fglasgow-exts    #-} -- For deriving Data/Typeable
+{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, PatternGuards, TypeSynonymInstances #-}
+
+-- --------------------------------------------------------------------------
 -- |
 -- Module      :  Operations.hs
 -- Copyright   :  (c) Spencer Janssen 2007
 -- License     :  BSD3-style (see LICENSE)
 --
 -- Maintainer  :  dons@cse.unsw.edu.au
--- Stability   :  stable
--- Portability :  portable
+-- Stability   :  unstable
+-- Portability :  not portable, Typeable deriving, mtl, posix
+--
+-- Operations.
 --
 -----------------------------------------------------------------------------
 
 module Operations where
 
-import Data.List
+import XMonad
+import qualified StackSet as W
+import {-# SOURCE #-} Config (borderWidth,logHook,manageHook,numlockMask,serialisedLayouts)
+
 import Data.Maybe
-import Data.Bits
+import Data.List            (nub, (\\), find, partition)
+import Data.Bits            ((.|.), (.&.), complement)
+import Data.Ratio
 import qualified Data.Map as M
+import qualified Data.Set as S
 
 import Control.Monad.State
-import Control.Arrow
-
-import System.Posix.Process
-import System.Environment
-import System.Directory
+import Control.Monad.Reader
+import Control.Arrow ((***), second)
 
+import System.IO
 import Graphics.X11.Xlib
+import Graphics.X11.Xinerama (getScreenInfo)
 import Graphics.X11.Xlib.Extras
 
-import XMonad
+-- ---------------------------------------------------------------------
+-- |
+-- Window manager operations
+-- manage. Add a new window to be managed in the current workspace.
+-- Bring it into focus.
+--
+-- Whether the window is already managed, or not, it is mapped, has its
+-- border set, and its event mask set.
+--
+manage :: Window -> X ()
+manage w = whenX (fmap not $ isClient w) $ withDisplay $ \d -> do
+    sh <- io $ getWMNormalHints d w
 
-import qualified StackSet as W
+    let isFixedSize = sh_min_size sh /= Nothing && sh_min_size sh == sh_max_size sh
+    isTransient <- isJust `liftM` io (getTransientForHint d w)
 
+    (sc, rr) <- floatLocation w
+    -- ensure that float windows don't go over the edge of the screen
+    let adjust (W.RationalRect x y wid h) | x + wid > 1 || y + h > 1 || x < 0 || y < 0
+                                              = W.RationalRect (0.5 - wid/2) (0.5 - h/2) wid h
+        adjust r = r
+
+        f ws | isFixedSize || isTransient = W.float w (adjust rr) . W.insertUp w . W.view i $ ws
+             | otherwise                  = W.insertUp w ws
+            where i = fromMaybe (W.tag . W.workspace . W.current $ ws) $ W.lookupWorkspace sc ws
+
+    n <- fmap (fromMaybe "") $ io $ fetchName d w
+    (ClassHint rn rc) <- io $ getClassHint d w
+    g <- manageHook w n rn rc `catchX` return id
+    windows (g . f)
+
+-- | unmanage. A window no longer exists, remove it from the window
+-- list, on whatever workspace it is.
+--
+-- should also unmap?
+--
+unmanage :: Window -> X ()
+unmanage w = do
+    windows (W.delete w)
+    setWMState w 0 {-withdrawn-}
+    modify (\s -> s {mapped = S.delete w (mapped s), waitingUnmap = M.delete w (waitingUnmap s)})
+
+-- | Modify the size of the status gap at the top of the current screen
+-- Taking a function giving the current screen, and current geometry.
+modifyGap :: (Int -> (Int,Int,Int,Int) -> (Int,Int,Int,Int)) -> X ()
+modifyGap f = do
+    windows $ \ws@(W.StackSet { W.current = c@(W.Screen { W.screenDetail = sd }) }) ->
+        let n = fromIntegral . W.screen $ c
+            g = f n . statusGap $ sd
+        in ws { W.current = c { W.screenDetail = sd { statusGap = g } } }
+
+-- | Kill the currently focused client. If we do kill it, we'll get a
+-- delete notify back from X.
+--
+-- There are two ways to delete a window. Either just kill it, or if it
+-- supports the delete protocol, send a delete event (e.g. firefox)
+--
+kill :: X ()
+kill = withDisplay $ \d -> withFocused $ \w -> do
+    wmdelt <- atom_WM_DELETE_WINDOW  ;  wmprot <- atom_WM_PROTOCOLS
+
+    protocols <- io $ getWMProtocols d w
+    io $ if wmdelt `elem` protocols
+        then allocaXEvent $ \ev -> do
+                setEventType ev clientMessage
+                setClientMessageEvent ev w wmprot 32 wmdelt 0
+                sendEvent d w False noEventMask ev
+        else killClient d w >> return ()
 
 -- ---------------------------------------------------------------------
 -- Managing windows
 
--- | refresh. Refresh the currently focused window. Resizes to full
--- screen and raises the window.
-refresh :: X ()
-refresh = do
-    XState {workspace = ws, xineScreens = xinesc
-           ,display   = d ,layoutDescs = fls  ,defaultLayoutDesc = dfltfl } <- get
+data LayoutMessages = Hide | ReleaseResources deriving ( Typeable, Eq )
 
-    flip mapM_ (M.assocs (W.screen2ws ws)) $ \(scn, n) -> do
-        let sc =  genericIndex xinesc scn -- temporary coercion!
-            fl = M.findWithDefault dfltfl n fls
-        mapM_ (\(w, rect) -> io $ moveWindowInside d w rect) $
-            case layoutType fl of
-                Full -> fmap (flip (,) sc) $ maybeToList $ W.peekStack n ws
-                Tall -> tile  (tileFraction fl) sc $ W.index n ws
-                Wide -> vtile (tileFraction fl) sc $ W.index n ws
-        whenJust (W.peekStack n ws) (io . raiseWindow d)
-    whenJust (W.peek ws) setFocus
-    clearEnterEvents
-
--- | clearEnterEvents.  Remove all window entry events from the event queue.
-clearEnterEvents :: X ()
-clearEnterEvents = do
-    d <- gets display
-    io $ sync d False
-    io $ allocaXEvent $ \p -> fix $ \again -> do
-        more <- checkMaskEvent d enterWindowMask p
-        when more again
-
--- | tile.  Compute the positions for windows in horizontal layout
--- mode.
---
-tile :: Rational -> Rectangle -> [Window] -> [(Window, Rectangle)]
-tile _ _ []    = []
-tile _ d [w]   = [(w, d)]
-tile r (Rectangle sx sy sw sh) (w:s)
- = (w, Rectangle sx sy (fromIntegral lw) sh) : zipWith f [sy, sy + rh ..] s
- where
-    lw = floor $ fromIntegral sw * r
-    rw = sw - fromIntegral lw
-    rh = fromIntegral sh `div` fromIntegral (length s)
-    f i a = (a, Rectangle (sx + lw) i rw (fromIntegral rh))
-
--- | vtile. Tile vertically.
-vtile :: Rational -> Rectangle -> [Window] -> [(Window, Rectangle)]
-vtile r rect = map (second flipRect) . tile r (flipRect rect)
-
--- | Flip rectangles around
-flipRect :: Rectangle -> Rectangle
-flipRect (Rectangle rx ry rw rh) = (Rectangle ry rx rh rw)
-
--- | switchLayout.  Switch to another layout scheme.  Switches the
--- current workspace. By convention, a window set as master in Tall mode
--- remains as master in Wide mode. When switching from full screen to a
--- tiling mode, the currently focused window becomes a master. When
--- switching back , the focused window is uppermost.
---
-switchLayout :: X ()
-switchLayout = layout $ \fl -> fl { layoutType = rotateLayout (layoutType fl) }
-
--- | changeSplit.  Changes the window split.
-changeSplit :: Rational -> X ()
-changeSplit delta = layout $ \fl ->
-    fl { tileFraction = min 1 (max 0 (tileFraction fl + delta)) }
-
--- | layout. Modify the current workspace's layout with a pure
--- function and refresh.
-layout :: (LayoutDesc -> LayoutDesc) -> X ()
-layout f = do
-    modify $ \s ->
-        let fls = layoutDescs s
-            n   = W.current . workspace $ s
-            fl  = M.findWithDefault (defaultLayoutDesc s) n fls
-        in s { layoutDescs = M.insert n (f fl) fls }
-    refresh
+instance Message LayoutMessages
 
 -- | windows. Modify the current window list with a pure function, and refresh
 windows :: (WindowSet -> WindowSet) -> X ()
 windows f = do
-    modify $ \s -> s { workspace = f (workspace s) }
-    refresh
-    ws <- gets workspace
-    trace (show ws) -- log state changes to stderr
+    XState { windowset = old } <- get
+    let oldvisible = concatMap (W.integrate' . W.stack . W.workspace) $ W.current old : W.visible old
+        ws = f old
+    XConf { display = d , normalBorder = nbc, focusedBorder = fbc } <- ask
+    mapM_ setInitialProperties (W.allWindows ws \\ W.allWindows old)
+    whenJust (W.peek old) $ \otherw -> io $ setWindowBorder d otherw nbc
+    modify (\s -> s { windowset = ws })
 
--- | hide. Hide a window by moving it offscreen.
+    -- notify non visibility
+    let tags_oldvisible = map (W.tag . W.workspace) $ W.current old : W.visible old
+        gottenhidden    = filter (`elem` tags_oldvisible) $ map W.tag $ W.hidden ws
+    sendMessageToWorkspaces Hide gottenhidden
+
+    -- for each workspace, layout the currently visible workspaces
+    let allscreens     = W.screens ws
+        summed_visible = scanl (++) [] $ map (W.integrate' . W.stack . W.workspace) allscreens
+    visible <- fmap concat $ forM (zip allscreens summed_visible) $ \ (w, vis) -> do
+        let n      = W.tag (W.workspace w)
+            this   = W.view n ws
+            l = W.layout (W.workspace w)
+            flt = filter (flip M.member (W.floating ws)) (W.index this)
+            tiled = (W.stack . W.workspace . W.current $ this)
+                    >>= W.filter (not . flip M.member (W.floating ws))
+                    >>= W.filter (not . (`elem` vis))
+            (SD (Rectangle sx sy sw sh)
+                (gt,gb,gl,gr))          = W.screenDetail w
+            viewrect = Rectangle (sx + fromIntegral gl)        (sy + fromIntegral gt)
+                                 (sw - fromIntegral (gl + gr)) (sh - fromIntegral (gt + gb))
+
+        -- just the tiled windows:
+        -- now tile the windows on this workspace, modified by the gap
+        (rs, ml') <- runLayout l viewrect tiled `catchX` runLayout (Layout Full) viewrect tiled
+        mapM_ (uncurry tileWindow) rs
+        whenJust ml' $ \l' -> runOnWorkspaces (\ww -> if W.tag ww == n
+                                                      then return $ ww { W.layout = l'}
+                                                      else return ww)
+
+        -- now the floating windows:
+        -- move/resize the floating windows, if there are any
+        forM_ flt $ \fw -> whenJust (M.lookup fw (W.floating ws)) $
+          \(W.RationalRect rx ry rw rh) -> do
+            tileWindow fw $ Rectangle
+                (sx + floor (toRational sw*rx)) (sy + floor (toRational sh*ry))
+                (floor (toRational sw*rw)) (floor (toRational sh*rh))
+
+        let vs = flt ++ map fst rs
+        io $ restackWindows d vs
+        -- return the visible windows for this workspace:
+        return vs
+
+    whenJust (W.peek ws) $ \w -> io $ setWindowBorder d w fbc
+    setTopFocus
+    userCode logHook
+    -- io performGC -- really helps, but seems to trigger GC bugs?
+
+    -- hide every window that was potentially visible before, but is not
+    -- given a position by a layout now.
+    mapM_ hide (nub oldvisible \\ visible)
+
+    clearEvents enterWindowMask
+
+-- | setWMState.  set the WM_STATE property
+setWMState :: Window -> Int -> X ()
+setWMState w v = withDisplay $ \dpy -> do
+    a <- atom_WM_STATE
+    io $ changeProperty32 dpy w a a propModeReplace [fromIntegral v, fromIntegral none]
+
+-- | hide. Hide a window by unmapping it, and setting Iconified.
 hide :: Window -> X ()
-hide w = withDisplay $ \d -> do
-    (sw,sh) <- gets dimensions
-    io $ moveWindow d w (2*fromIntegral sw) (2*fromIntegral sh)
+hide w = whenX (gets (S.member w . mapped)) $ withDisplay $ \d -> do
+    io $ do selectInput d w (clientMask .&. complement structureNotifyMask)
+            unmapWindow d w
+            selectInput d w clientMask
+    setWMState w 3 --iconic
+    -- this part is key: we increment the waitingUnmap counter to distinguish
+    -- between client and xmonad initiated unmaps.
+    modify (\s -> s { waitingUnmap = M.insertWith (+) w 1 (waitingUnmap s)
+                    , mapped       = S.delete w (mapped s) })
+
+-- | reveal. Show a window by mapping it and setting Normal
+-- this is harmless if the window was already visible
+reveal :: Window -> X ()
+reveal w = withDisplay $ \d -> do
+    setWMState w 1 --normal
+    io $ mapWindow d w
+    modify (\s -> s { mapped = S.insert w (mapped s) })
+
+-- | The client events that xmonad is interested in
+clientMask :: EventMask
+clientMask = structureNotifyMask .|. enterWindowMask .|. propertyChangeMask
+
+-- | Set some properties when we initially gain control of a window
+setInitialProperties :: Window -> X ()
+setInitialProperties w = asks normalBorder >>= \nb -> withDisplay $ \d -> io $ do
+    selectInput d w $ clientMask
+    setWindowBorderWidth d w borderWidth
+    -- we must initially set the color of new windows, to maintain invariants
+    -- required by the border setting in 'windows'
+    setWindowBorder d w nb
+
+-- | refresh. Render the currently visible workspaces, as determined by
+-- the StackSet. Also, set focus to the focused window.
+--
+-- This is our 'view' operation (MVC), in that it pretty prints our model
+-- with X calls.
+--
+refresh :: X ()
+refresh = windows id
+
+-- | clearEvents.  Remove all events of a given type from the event queue.
+clearEvents :: EventMask -> X ()
+clearEvents mask = withDisplay $ \d -> io $ do
+    sync d False
+    allocaXEvent $ \p -> fix $ \again -> do
+        more <- checkMaskEvent d mask p
+        when more again -- beautiful
+
+-- | tileWindow. Moves and resizes w such that it fits inside the given
+-- rectangle, including its border.
+tileWindow :: Window -> Rectangle -> X ()
+tileWindow w r = withDisplay $ \d -> do
+    bw <- (fromIntegral . wa_border_width) `liftM` io (getWindowAttributes d w)
+    -- give all windows at least 1x1 pixels
+    let least x | x <= bw*2  = 1
+                | otherwise  = x - bw*2
+    io $ moveResizeWindow d w (rect_x r) (rect_y r)
+                              (least $ rect_width r) (least $ rect_height r)
+    reveal w
+
+-- ---------------------------------------------------------------------
+
+-- | rescreen.  The screen configuration may have changed (due to
+-- xrandr), update the state and refresh the screen, and reset the gap.
+rescreen :: X ()
+rescreen = do
+    xinesc <- withDisplay (io . getScreenInfo)
+
+    windows $ \ws@(W.StackSet { W.current = v, W.visible = vs, W.hidden = hs }) ->
+        let (xs, ys) = splitAt (length xinesc) $ map W.workspace (v:vs) ++ hs
+            (a:as)   = zipWith3 W.Screen xs [0..] $ zipWith SD xinesc gs
+            sgs      = map (statusGap . W.screenDetail) (v:vs)
+            gs       = take (length xinesc) (sgs ++ repeat (0,0,0,0))
+        in  ws { W.current = a
+               , W.visible = as
+               , W.hidden  = ys }
 
 -- ---------------------------------------------------------------------
--- Window operations
 
 -- | setButtonGrab. Tell whether or not to intercept clicks on a given window
-buttonsToGrab :: [Button]
-buttonsToGrab = [button1, button2, button3]
-
 setButtonGrab :: Bool -> Window -> X ()
-setButtonGrab True  w = withDisplay $ \d -> io $
-    flip mapM_ buttonsToGrab $ \b ->
-        grabButton d b anyModifier w False
-                   (buttonPressMask .|. buttonReleaseMask)
+setButtonGrab grab w = withDisplay $ \d -> io $
+    if grab
+        then forM_ [button1, button2, button3] $ \b ->
+            grabButton d b anyModifier w False buttonPressMask
                        grabModeAsync grabModeSync none none
+        else ungrabButton d anyButton anyModifier w
 
-setButtonGrab False w = withDisplay $ \d -> io $
-    flip mapM_ buttonsToGrab $ \b ->
-        ungrabButton d b anyModifier w
-
--- | moveWindowInside. Moves and resizes w such that it fits inside the given
--- rectangle, including its border.
-moveWindowInside :: Display -> Window -> Rectangle -> IO ()
-moveWindowInside d w r = do
-    bw <- (fromIntegral . wa_border_width) `liftM` getWindowAttributes d w
-    moveResizeWindow d w (rect_x r) (rect_y r)
-                         (rect_width  r - bw*2)
-                         (rect_height r - bw*2)
-
--- | manage. Add a new window to be managed in the current workspace. Bring it into focus.
--- If the window is already under management, it is just raised.
---
-manage :: Window -> X ()
-manage w = do
-    withDisplay $ \d -> io $ do
-        selectInput d w $ structureNotifyMask .|. enterWindowMask .|. propertyChangeMask
-        mapWindow d w
-    windows $ W.push w
-
--- | unmanage. A window no longer exists, remove it from the window
--- list, on whatever workspace it is.
-unmanage :: Window -> X ()
-unmanage w = do
-    windows $ W.delete w
-    withServerX $ do
-      setTopFocus
-      withDisplay $ \d -> io (sync d False)
-      -- TODO, everything operates on the current display, so wrap it up.
-
--- | Grab the X server (lock it) from the X monad
-withServerX :: X () -> X ()
-withServerX f = withDisplay $ \dpy -> do
-    io $ grabServer dpy
-    f
-    io $ ungrabServer dpy
-
-safeFocus :: Window -> X ()
-safeFocus w = do ws <- gets workspace
-                 if W.member w ws
-                    then setFocus w
-                    else do b <- isRoot w
-                            when b setTopFocus
-
--- | Explicitly set the keyboard focus to the given window
-setFocus :: Window -> X ()
-setFocus w = do
-    ws <- gets workspace
-
-    -- clear mouse button grab and border on other windows
-    flip mapM_ (W.visibleWorkspaces ws) $ \n -> do
-        flip mapM_ (W.index n ws) $ \otherw -> do
-            setButtonGrab True otherw
-            setBorder otherw 0xdddddd
-
-    withDisplay $ \d -> io $ setInputFocus d w revertToPointerRoot 0
-    setButtonGrab False w
-    setBorder w 0xff0000    -- make this configurable
-
-    -- This does not use 'windows' intentionally.  'windows' calls refresh,
-    -- which means infinite loops.
-    modify $ \s -> s { workspace = W.raiseFocus w (workspace s) }
+-- ---------------------------------------------------------------------
+-- Setting keyboard focus
 
 -- | Set the focus to the window on top of the stack, or root
 setTopFocus :: X ()
-setTopFocus = do
-    ws <- gets workspace
-    case W.peek ws of
-        Just new -> setFocus new
-        Nothing  -> gets theRoot >>= setFocus
+setTopFocus = withWindowSet $ maybe (setFocusX =<< asks theRoot) setFocusX . W.peek
 
--- | Set the border color for a particular window.
-setBorder :: Window -> Pixel -> X ()
-setBorder w p = withDisplay $ \d -> io $ setWindowBorder d w p
+-- | Set focus explicitly to window 'w' if it is managed by us, or root.
+-- This happens if X notices we've moved the mouse (and perhaps moved
+-- the mouse to a new screen).
+focus :: Window -> X ()
+focus w = withWindowSet $ \s -> do
+    if W.member w s then when (W.peek s /= Just w) $ windows (W.focusWindow w)
+                    else whenX (isRoot w) $ setFocusX w
 
--- | raise. focus to window at offset 'n' in list.
--- The currently focused window is always the head of the list
-raise :: Ordering -> X ()
-raise = windows . W.rotate
+-- | Call X to set the keyboard focus details.
+setFocusX :: Window -> X ()
+setFocusX w = withWindowSet $ \ws -> do
+    dpy <- asks display
 
--- | promote. Move the currently focused window into the master frame
-promote :: X ()
-promote = windows W.promote
+    -- clear mouse button grab and border on other windows
+    forM_ (W.current ws : W.visible ws) $ \wk -> do
+        forM_ (W.index (W.view (W.tag (W.workspace wk)) ws)) $ \otherw -> do
+            setButtonGrab True otherw
 
--- | Kill the currently focused client
-kill :: X ()
-kill = withDisplay $ \d -> do
-    ws <- gets workspace
-    whenJust (W.peek ws) $ \w -> do
-        protocols <- io $ getWMProtocols d w
-        XState {wmdelete = wmdelt, wmprotocols = wmprot} <- get
-        if wmdelt `elem` protocols
-            then io $ allocaXEvent $ \ev -> do
-                    setEventType ev clientMessage
-                    setClientMessageEvent ev w wmprot 32 wmdelt 0
-                    sendEvent d w False noEventMask ev
-            else io (killClient d w) >> return ()
+    -- If we ungrab buttons on the root window, we lose our mouse bindings.
+    whenX (not `liftM` isRoot w) $ setButtonGrab False w
+    io $ do setInputFocus dpy w revertToPointerRoot 0
+            -- raiseWindow dpy w
 
--- | tag. Move a window to a new workspace, 0 indexed.
-tag :: WorkspaceId -> X ()
-tag n = do
-    ws <- gets workspace
-    let m = W.current ws -- :: WorkspaceId
-    when (n /= m) $
-        whenJust (W.peek ws) $ \w -> do
-            hide w
-            windows $ W.shift n
+------------------------------------------------------------------------
+-- Message handling
 
--- | view. Change the current workspace to workspace at offset n (0 indexed).
-view :: WorkspaceId -> X ()
-view n = do
-    ws <- gets workspace
-    let m = W.current ws
-    windows $ W.view n
-    ws' <- gets workspace
-    -- If the old workspace isn't visible anymore, we have to hide the windows
-    -- in case we're switching to an empty workspace.
-    when (m `notElem` (W.visibleWorkspaces ws')) (mapM_ hide (W.index m ws))
-    clearEnterEvents
-    setTopFocus
+-- | Throw a message to the current LayoutClass possibly modifying how we
+-- layout the windows, then refresh.
+sendMessage :: Message a => a -> X ()
+sendMessage a = do
+    w <- (W.workspace . W.current) `fmap` gets windowset
+    ml' <- handleMessage (W.layout w) (SomeMessage a) `catchX` return Nothing
+    whenJust ml' $ \l' -> do
+        windows $ \ws -> ws { W.current = (W.current ws)
+                                { W.workspace = (W.workspace $ W.current ws)
+                                  { W.layout = l' }}}
 
--- | 'screenWorkspace sc' returns the workspace number viewed by 'sc'.
-screenWorkspace :: ScreenId -> X WorkspaceId
-screenWorkspace sc = fmap (fromMaybe 0 . W.workspace sc) (gets workspace)
+-- | Send a message to a list of workspaces' layouts, without necessarily refreshing.
+sendMessageToWorkspaces :: Message a => a -> [WorkspaceId] -> X ()
+sendMessageToWorkspaces a l = runOnWorkspaces $ \w ->
+   if W.tag w `elem` l
+      then do ml' <- handleMessage (W.layout w) (SomeMessage a) `catchX` return Nothing
+              return $ w { W.layout = maybe (W.layout w) id ml' }
+      else return w
+
+-- | Send a message to all visible layouts, without necessarily refreshing.
+-- This is how we implement the hooks, such as UnDoLayout.
+broadcastMessage :: Message a => a -> X ()
+broadcastMessage a = runOnWorkspaces $ \w -> do
+    ml' <- handleMessage (W.layout w) (SomeMessage a) `catchX` return Nothing
+    return $ w { W.layout = maybe (W.layout w) id ml' }
+
+-- | This is basically a map function, running a function in the X monad on
+-- each workspace with the output of that function being the modified workspace.
+runOnWorkspaces :: (WindowSpace -> X WindowSpace) -> X ()
+runOnWorkspaces job =do
+    ws <- gets windowset
+    h <- mapM job $ W.hidden ws
+    c:v <- mapM (\s -> fmap (\w -> s { W.workspace = w}) $ job (W.workspace s))
+             $ W.current ws : W.visible ws
+    modify $ \s -> s { windowset = ws { W.current = c, W.visible = v, W.hidden = h } }
+
+-- | Set the layout of the currently viewed workspace
+setLayout :: Layout Window -> X ()
+setLayout l = do
+    ss@(W.StackSet { W.current = c@(W.Screen { W.workspace = ws })}) <- gets windowset
+    handleMessage (W.layout ws) (SomeMessage ReleaseResources)
+    windows $ const $ ss {W.current = c { W.workspace = ws { W.layout = l } } }
+
+-- | X Events are valid Messages
+instance Message Event
+
+------------------------------------------------------------------------
+-- LayoutClass selection manager
+
+-- | A layout that allows users to switch between various layout options.
+-- This layout accepts three Messages:
+--
+-- >    NextLayout
+-- >    PrevLayout
+-- >    JumpToLayout.
+--
+data ChangeLayout = NextLayout | PrevLayout | JumpToLayout String
+                 deriving (Eq, Show, Typeable)
+
+instance Message ChangeLayout
+
+instance ReadableLayout Window where
+    readTypes = Layout (Select []) :
+                Layout Full : Layout (Tall 1 0.1 0.5) :
+                Layout (Mirror $ Tall 1 0.1 0.5) :
+                serialisedLayouts
+
+data Select a = Select [Layout a] deriving (Show, Read)
+
+instance ReadableLayout a => LayoutClass Select a where
+    doLayout (Select (l:ls)) r s =
+        second (fmap (Select . (:ls))) `fmap` doLayout l r s
+    doLayout (Select []) r s      =
+        second (const Nothing) `fmap` doLayout Full r s
+
+    -- respond to messages only when there's an actual choice:
+    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 -- each branch has a different type
+                 mlls' <- mapM (flip handleMessage m) (l:ls)
+                 let lls' = zipWith (flip maybe id) (l:ls) mlls'
+                 return (Just (Select lls'))
+
+        where rls []     = []
+              rls (x:xs) = xs ++ [x]
+              rls' = reverse . rls . reverse
+
+              j s zs = case partition ((s ==) . description) zs of (xs,ys) -> xs++ys
+
+              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 =
+       fmap (Select . (:ls)) `fmap` handleMessage l m
+
+    -- Unless there is no layout...
+    handleMessage (Select []) _ = return Nothing
+
+    description (Select (x:_)) = description x
+    description _              = "default"
+
+--
+-- | Builtin layout algorithms:
+--
+-- > fullscreen mode
+-- > tall mode
+--
+-- The latter algorithms support the following operations:
+--
+-- >    Shrink
+-- >    Expand
+--
+data Resize     = Shrink | Expand   deriving Typeable
+
+-- | You can also increase the number of clients in the master pane
+data IncMasterN = IncMasterN Int    deriving Typeable
+
+instance Message Resize
+instance Message IncMasterN
+
+-- | Simple fullscreen mode, just render all windows fullscreen.
+data Full a = Full deriving (Show, Read)
+
+instance LayoutClass Full a
+
+-- | The inbuilt tiling mode of xmonad, and its operations.
+data Tall a = Tall Int Rational Rational deriving (Show, Read)
+
+instance LayoutClass Tall a where
+    doLayout (Tall nmaster _ frac) r =
+        return . (flip (,) Nothing) .
+        ap zip (tile frac r nmaster . length) . W.integrate
+
+    pureMessage (Tall nmaster delta frac) m = msum [fmap resize (fromMessage m)
+                                                   ,fmap incmastern (fromMessage m)]
+        where resize Shrink = Tall nmaster delta (max 0 $ frac-delta)
+              resize Expand = Tall nmaster delta (min 1 $ frac+delta)
+              incmastern (IncMasterN d) = Tall (max 0 (nmaster+d)) delta frac
+    description _ = "Tall"
+
+-- | Mirror a rectangle
+mirrorRect :: Rectangle -> Rectangle
+mirrorRect (Rectangle rx ry rw rh) = (Rectangle ry rx rh rw)
+
+-- | Mirror a layout, compute its 90 degree rotated form.
+data Mirror l a = Mirror (l a) deriving (Show, Read)
+
+instance LayoutClass l a => LayoutClass (Mirror l) a where
+    doLayout (Mirror l) r s = (map (second mirrorRect) *** fmap Mirror)
+                                `fmap` doLayout l (mirrorRect r) s
+    handleMessage (Mirror l) = fmap (fmap Mirror) . handleMessage l
+    description (Mirror l) = "Mirror "++ description l
+
+-- | tile.  Compute the positions for windows using the default 2 pane tiling algorithm.
+--
+-- The screen is divided (currently) into two panes. all clients are
+-- then partioned between these two panes. one pane, the `master', by
+-- convention has the least number of windows in it (by default, 1).
+-- the variable `nmaster' controls how many windows are rendered in the
+-- master pane.
+--
+-- `delta' specifies the ratio of the screen to resize by.
+--
+-- 'frac' specifies what proportion of the screen to devote to the
+-- master area.
+--
+tile :: Rational -> Rectangle -> Int -> Int -> [Rectangle]
+tile f r nmaster n = if n <= nmaster || nmaster == 0
+    then splitVertically n r
+    else splitVertically nmaster r1 ++ splitVertically (n-nmaster) r2 -- two columns
+  where (r1,r2) = splitHorizontallyBy f r
+
+--
+-- Divide the screen vertically into n subrectangles
+--
+splitVertically, splitHorizontally :: Int -> Rectangle -> [Rectangle]
+splitVertically n r | n < 2 = [r]
+splitVertically n (Rectangle sx sy sw sh) = Rectangle sx sy sw smallh :
+    splitVertically (n-1) (Rectangle sx (sy+fromIntegral smallh) sw (sh-smallh))
+  where smallh = sh `div` fromIntegral n --hmm, this is a fold or map.
+
+splitHorizontally n = map mirrorRect . splitVertically n . mirrorRect
+
+-- Divide the screen into two rectangles, using a rational to specify the ratio
+splitHorizontallyBy, splitVerticallyBy :: RealFrac r => r -> Rectangle -> (Rectangle, Rectangle)
+splitHorizontallyBy f (Rectangle sx sy sw sh) =
+    ( Rectangle sx sy leftw sh
+    , Rectangle (sx + fromIntegral leftw) sy (sw-fromIntegral leftw) sh)
+  where leftw = floor $ fromIntegral sw * f
+
+-- | XXX comment me
+splitVerticallyBy f = (mirrorRect *** mirrorRect) . splitHorizontallyBy f . mirrorRect
+
+------------------------------------------------------------------------
+-- Utilities
+
+-- | Return workspace visible on screen 'sc', or Nothing.
+screenWorkspace :: ScreenId -> X (Maybe WorkspaceId)
+screenWorkspace sc = withWindowSet $ return . W.lookupWorkspace sc
+
+-- | Apply an X operation to the currently focused window, if there is one.
+withFocused :: (Window -> X ()) -> X ()
+withFocused f = withWindowSet $ \w -> whenJust (W.peek w) f
 
 -- | True if window is under management by us
 isClient :: Window -> X Bool
-isClient w = liftM (W.member w) (gets workspace)
+isClient w = withWindowSet $ return . W.member w
 
--- | Restart xmonad by exec()'ing self. This doesn't save state and xmonad has
--- to be in PATH for this to work.
-restart :: IO ()
-restart = do
-    prog      <- getProgName
-    prog_path <- findExecutable prog
-    case prog_path of
-        Nothing -> return ()    -- silently fail
-        Just p  -> do args <- getArgs
-                      executeFile p True args Nothing
+-- | Combinations of extra modifier masks we need to grab keys\/buttons for.
+-- (numlock and capslock)
+extraModifiers :: [KeyMask]
+extraModifiers = [0, numlockMask, lockMask, numlockMask .|. lockMask ]
+
+-- | Strip numlock\/capslock from a mask
+cleanMask :: KeyMask -> KeyMask
+cleanMask = (complement (numlockMask .|. lockMask) .&.)
+
+-- | Get the Pixel value for a named color
+initColor :: Display -> String -> IO Pixel
+initColor dpy c = (color_pixel . fst) `liftM` allocNamedColor dpy colormap c
+    where colormap = defaultColormap dpy (defaultScreen dpy)
+
+------------------------------------------------------------------------
+-- | Floating layer support
+
+-- | Given a window, find the screen it is located on, and compute
+-- the geometry of that window wrt. that screen.
+floatLocation :: Window -> X (ScreenId, W.RationalRect)
+floatLocation w = withDisplay $ \d -> do
+    ws <- gets windowset
+    wa <- io $ getWindowAttributes d w
+
+    -- XXX horrible
+    let sc = fromMaybe (W.current ws) $ find (pointWithin (fi $ wa_x wa) (fi $ wa_y wa) . screenRect . W.screenDetail) $ W.screens ws
+        sr = screenRect . W.screenDetail $ sc
+        bw = fi . wa_border_width $ wa
+        rr = W.RationalRect ((fi (wa_x wa) - fi (rect_x sr)) % fi (rect_width sr))
+                            ((fi (wa_y wa) - fi (rect_y sr)) % fi (rect_height sr))
+                            (fi (wa_width  wa + bw*2) % fi (rect_width sr))
+                            (fi (wa_height wa + bw*2) % fi (rect_height sr))
+
+    return (W.screen $ sc, rr)
+  where fi x = fromIntegral x
+        pointWithin :: Integer -> Integer -> Rectangle -> Bool
+        pointWithin x y r = x >= fi (rect_x r) &&
+                            x <  fi (rect_x r) + fi (rect_width r) &&
+                            y >= fi (rect_y r) &&
+                            y <  fi (rect_y r) + fi (rect_height r)
+
+-- | Make a tiled window floating, using its suggested rectangle
+float :: Window -> X ()
+float w = do
+    (sc, rr) <- floatLocation w
+    windows $ \ws -> W.float w rr . fromMaybe ws $ do
+        i <- W.findIndex w ws
+        guard $ i `elem` map (W.tag . W.workspace) (W.screens ws)
+        f <- W.peek ws
+        sw <- W.lookupWorkspace sc ws
+        return (W.focusWindow f . W.shiftWin sw w $ ws)
+
+-- ---------------------------------------------------------------------
+-- Mouse handling
+
+-- | Accumulate mouse motion events
+mouseDrag :: (Position -> Position -> X ()) -> X () -> X ()
+mouseDrag f done = do
+    drag <- gets dragging
+    case drag of
+        Just _ -> return () -- error case? we're already dragging
+        Nothing -> do
+            XConf { theRoot = root, display = d } <- ask
+            io $ grabPointer d root False (buttonReleaseMask .|. pointerMotionMask)
+                    grabModeAsync grabModeAsync none none currentTime
+            modify $ \s -> s { dragging = Just (motion, cleanup) }
+ where
+    cleanup = do
+        withDisplay $ io . flip ungrabPointer currentTime
+        modify $ \s -> s { dragging = Nothing }
+        done
+    motion x y = do z <- f x y
+                    clearEvents pointerMotionMask
+                    return z
+
+-- | XXX comment me
+mouseMoveWindow :: Window -> X ()
+mouseMoveWindow w = whenX (isClient w) $ withDisplay $ \d -> do
+    io $ raiseWindow d w
+    wa <- io $ getWindowAttributes d w
+    (_, _, _, ox', oy', _, _, _) <- io $ queryPointer d w
+    let ox = fromIntegral ox'
+        oy = fromIntegral oy'
+    mouseDrag (\ex ey -> io $ moveWindow d w (fromIntegral (fromIntegral (wa_x wa) + (ex - ox)))
+                                             (fromIntegral (fromIntegral (wa_y wa) + (ey - oy))))
+              (float w)
+
+-- | XXX comment me
+mouseResizeWindow :: Window -> X ()
+mouseResizeWindow w = whenX (isClient w) $ withDisplay $ \d -> do
+    io $ raiseWindow d w
+    wa <- io $ getWindowAttributes d w
+    sh <- io $ getWMNormalHints d w
+    io $ warpPointer d none w 0 0 0 0 (fromIntegral (wa_width wa)) (fromIntegral (wa_height wa))
+    mouseDrag (\ex ey -> do
+                 io $ resizeWindow d w `uncurry`
+                    applySizeHints sh (ex - fromIntegral (wa_x wa),
+                                       ey - fromIntegral (wa_y wa)))
+              (float w)
+
+-- ---------------------------------------------------------------------
+-- | Support for window size hints
+
+type D = (Dimension, Dimension)
+
+-- | Reduce the dimensions if needed to comply to the given SizeHints.
+applySizeHints :: Integral a => SizeHints -> (a,a) -> D
+applySizeHints sh (w,h) = applySizeHints' sh (fromIntegral $ max 1 w,
+                                              fromIntegral $ max 1 h)
+
+-- | XXX comment me
+applySizeHints' :: SizeHints -> D -> D
+applySizeHints' sh =
+      maybe id applyMaxSizeHint                   (sh_max_size   sh)
+    . maybe id (\(bw, bh) (w, h) -> (w+bw, h+bh)) (sh_base_size  sh)
+    . maybe id applyResizeIncHint                 (sh_resize_inc sh)
+    . maybe id applyAspectHint                    (sh_aspect     sh)
+    . maybe id (\(bw,bh) (w,h)   -> (w-bw, h-bh)) (sh_base_size  sh)
+
+-- | Reduce the dimensions so their aspect ratio falls between the two given aspect ratios.
+applyAspectHint :: (D, D) -> D -> D
+applyAspectHint ((minx, miny), (maxx, maxy)) x@(w,h)
+    | or [minx < 1, miny < 1, maxx < 1, maxy < 1] = x
+    | w * maxy > h * maxx                         = (h * maxx `div` maxy, h)
+    | w * miny < h * minx                         = (w, w * miny `div` minx)
+    | otherwise                                   = x
+
+-- | Reduce the dimensions so they are a multiple of the size increments.
+applyResizeIncHint :: D -> D -> D
+applyResizeIncHint (iw,ih) x@(w,h) =
+    if iw > 0 && ih > 0 then (w - w `mod` iw, h - h `mod` ih) else x
+
+-- | Reduce the dimensions if they exceed the given maximum dimensions.
+applyMaxSizeHint  :: D -> D -> D
+applyMaxSizeHint (mw,mh) x@(w,h) =
+    if mw > 0 && mh > 0 then (min w mw,min h mh) else x

README

@@ -1,42 +1,120 @@
                xmonad : a lightweight X11 window manager.
 
-Motivation:
+                           http://xmonad.org
 
-    dwm is great, but we can do better, building a more robust,
-    more correct window manager in fewer lines of code, using strong
-    static typing. Enter Haskell.
+------------------------------------------------------------------------
 
-    If the aim of dwm is to fit in under 2000 lines of C, the aim of
-    xmonad is to fit in under 500 lines of Haskell with similar functionality.
+About:
+
+    Xmonad is a tiling window manager for X. Windows are managed using
+    automatic tiling algorithms, which can be dynamically configured.
+    Windows are arranged so as to tile the screen without gaps, maximising
+    screen use. All features of the window manager are accessible 
+    from the keyboard: a mouse is strictly optional. Xmonad is written
+    and extensible in Haskell, and custom layout algorithms may be
+    implemented by the user in config files. A guiding principle of the
+    user interface is <i>predictability</i>: users should know in
+    advance precisely the window arrangement that will result from any
+    action, leading to an intuitive user interface.
+
+    Xmonad provides three tiling algorithms by default: tall, wide and
+    fullscreen. In tall or wide mode, all windows are visible and tiled
+    to fill the plane without gaps. In fullscreen mode only the focused
+    window is visible, filling the screen.  Alternative tiling
+    algorithms are provided as extensions. Sets of windows are grouped
+    together on virtual workspaces and each workspace retains its own
+    layout. Multiple physical monitors are supported via Xinerama,
+    allowing simultaneous display of several workspaces.
+
+    Adhering to a minimalist philosophy of doing one job, and doing it
+    well, the entire code base remains tiny, and is written to be simple
+    to understand and modify. By using Haskell as a configuration
+    language arbitrarily complex extensions may be implemented by the
+    user using a powerful `scripting' language, without needing to
+    modify the window manager directly. For example, users may write
+    their own tiling algorithms.
+
+------------------------------------------------------------------------
 
 Building:
 
-    Get the dependencies
+Get the dependencies
 
-    X11             http://hackage.haskell.org/cgi-bin/hackage-scripts/package/X11-1.2
-        (Unfortunately X11-1.2 does not work correctly on AMD64.  The latest
-         darcs version from http://darcs.haskell.org/packages/X11 does.)
+    Firstly, you'll need the C X11 library headers. On many platforms,
+    these come pre-installed. For others, such as Debian, you can get 
+    them from your package manager:
+
+        apt-get install libx11-dev
+
+    It is likely that you already have some of these dependencies.  To check
+    whether you've got a package run 'ghc-pkg list some_package_name'
 
     mtl             http://hackage.haskell.org/cgi-bin/hackage-scripts/package/mtl-1.0
-    unix            http://hackage.haskell.org/cgi-bin/hackage-scripts/package/unix-2.0 (included with ghc)
-
-    X11-extras:     darcs get http://darcs.haskell.org/~sjanssen/X11-extras
-
-    dmenu   2.{5,6,7} http://www.suckless.org/download/dmenu-2.7.tar.gz
+    unix            http://hackage.haskell.org/cgi-bin/hackage-scripts/package/unix-2.0 
+    X11             http://hackage.haskell.org/cgi-bin/hackage-scripts/package/X11-1.2.3
+    X11-extras:     http://hackage.haskell.org/cgi-bin/hackage-scripts/package/X11-extras-0.4
 
 And then build with Cabal:
 
-    runhaskell Setup.lhs configure --prefix=/home/dons
+    runhaskell Setup.lhs configure --prefix=$HOME
     runhaskell Setup.lhs build
-    runhaskell Setup.lhs install
+    runhaskell Setup.lhs install --user
 
-Then add:
+------------------------------------------------------------------------
 
-         exec /home/dons/bin/xmonad
+Notes for using the darcs version
 
-    to the last line of your .xsession file
+    If you're building the darcs version of xmonad, be sure to also
+    use the darcs version of X11-extras, which is developed concurrently
+    with xmonad.
+
+        darcs get http://code.haskell.org/X11-extras
+
+    Not using X11-extras from darcs, is the most common reason for the
+    darcs version of xmonad to fail to build.
+
+------------------------------------------------------------------------
+
+Running xmonad:
+
+    Add:
+
+         $HOME/bin/xmonad
+
+    to the last line of your .xsession or .xinitrc file.
+
+------------------------------------------------------------------------
+
+XMonadContrib
+
+    There are various contributed modules that can be used with xmonad.
+    Examples include an ion3-like tabbed layout, a prompt/program launcher,
+    and various other useful modules.  XMonadContrib is available at:
+
+    0.4 release:   http://www.xmonad.org/XMonadContrib-0.4.tar.gz
+
+    darcs version: darcs get http://code.haskell.org/XMonadContrib
+
+------------------------------------------------------------------------
+
+Other useful programs:
+
+ For a program dispatch menu:
+
+    dmenu           http://www.suckless.org/download/
+ or
+    gmrun           (in your package system)
+
+ For custom status bars:
+
+    dzen            http://gotmor.googlepages.com/dzen
+
+ A nicer xterm replacment, that supports resizing better:
+
+    urxvt           http://software.schmorp.de/pkg/rxvt-unicode.html
 
 Authors:
 
     Spencer Janssen
     Don Stewart
+    Jason Creighton

StackSet.hs

@@ -1,252 +1,565 @@
+{-# LANGUAGE PatternGuards #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  StackSet
 -- Copyright   :  (c) Don Stewart 2007
 -- License     :  BSD3-style (see LICENSE)
 --
--- Maintainer  :  dons@cse.unsw.edu.au
--- Stability   :  stable
--- Portability :  portable, needs GHC 6.6
---
------------------------------------------------------------------------------
---
--- The 'StackSet' data type encodes a set of stacks. A given stack in the
--- set is always current. Elements may appear only once in the entire
--- stack set.
---
--- A StackSet provides a nice data structure for window managers with
--- multiple physical screens, and multiple workspaces, where each screen
--- has a stack of windows, and a window may be on only 1 screen at any
--- given time.
+-- Maintainer  :  dons@galois.com
+-- Stability   :  experimental
+-- Portability :  portable, Haskell 98
 --
 
 module StackSet (
-    StackSet(..),           -- abstract
+        -- * Introduction
+        -- $intro
+        StackSet(..), Workspace(..), Screen(..), StackOrNot, Stack(..), RationalRect(..),
+        -- *  Construction
+        -- $construction
+        new, view, greedyView,
+        -- * Xinerama operations
+        -- $xinerama
+        lookupWorkspace,
+        screens, workspaces, allWindows,
+        -- *  Operations on the current stack
+        -- $stackOperations
+        peek, index, integrate, integrate', differentiate,
+        focusUp, focusDown, focusMaster, focusWindow,
+        tagMember, renameTag, ensureTags, member, findIndex, mapWorkspace, mapLayout,
+        -- * Modifying the stackset
+        -- $modifyStackset
+        insertUp, delete, delete', filter,
+        -- * Setting the master window
+        -- $settingMW
+        swapUp, swapDown, swapMaster, modify, modify', float, sink, -- needed by users
+        -- * Composite operations
+        -- $composite
+        shift, shiftWin,
 
-    screen, peekStack, index, empty, peek, push, delete, member,
-    raiseFocus, rotate, promote, shift, view, workspace, fromList,
-    toList, size, visibleWorkspaces, swap {- helper -}
+        -- for testing
+        abort
     ) where
 
-import Data.Maybe
-import qualified Data.List     as L (delete,genericLength,elemIndex)
-import qualified Data.Map      as M
+import Prelude hiding (filter)
+import Data.Maybe   (listToMaybe,fromJust)
+import qualified Data.List as L (deleteBy,find,splitAt,filter,nub)
+import Data.List ( (\\) )
+import qualified Data.Map  as M (Map,insert,delete,empty)
+
+-- $intro
+--
+-- The 'StackSet' data type encodes a window manager abstraction. The
+-- window manager is a set of virtual workspaces. On each workspace is a
+-- stack of windows. A given workspace is always current, and a given
+-- window on each workspace has focus. The focused window on the current
+-- workspace is the one which will take user input. It can be visualised
+-- as follows:
+--
+-- > Workspace  { 0*}   { 1 }   { 2 }   { 3 }   { 4 }
+-- >
+-- > Windows    [1      []      [3*     [6*]    []
+-- >            ,2*]            ,4
+-- >                            ,5]
+--
+-- Note that workspaces are indexed from 0, windows are numbered
+-- uniquely. A '*' indicates the window on each workspace that has
+-- focus, and which workspace is current.
+--
+-- Zipper
+--
+-- We encode all the focus tracking directly in the data structure, with a 'zipper':
+--
+--    A Zipper is essentially an `updateable' and yet pure functional
+--    cursor into a data structure. Zipper is also a delimited
+--    continuation reified as a data structure.
+--
+--    The Zipper lets us replace an item deep in a complex data
+--    structure, e.g., a tree or a term, without an  mutation.  The
+--    resulting data structure will share as much of its components with
+--    the old structure as possible.
+--
+--      Oleg Kiselyov, 27 Apr 2005, haskell\@, "Zipper as a delimited continuation"
+--
+-- We use the zipper to keep track of the focused workspace and the
+-- focused window on each workspace, allowing us to have correct focus
+-- by construction. We closely follow Huet's original implementation:
+--
+--      G. Huet, /Functional Pearl: The Zipper/,
+--      1997, J. Functional Programming 75(5):549-554.
+-- and:
+--      R. Hinze and J. Jeuring, /Functional Pearl: The Web/.
+--
+-- and Conor McBride's zipper differentiation paper.
+-- Another good reference is:
+--
+--      The Zipper, Haskell wikibook
+--
+-- Xinerama support:
+--
+-- Xinerama in X11 lets us view multiple virtual workspaces
+-- simultaneously. While only one will ever be in focus (i.e. will
+-- receive keyboard events), other workspaces may be passively viewable.
+-- We thus need to track which virtual workspaces are associated
+-- (viewed) on which physical screens. We use a simple Map Workspace
+-- Screen for this.
+--
+-- Master and Focus
+--
+-- Each stack tracks a focused item, and for tiling purposes also tracks
+-- a 'master' position. The connection between 'master' and 'focus'
+-- needs to be well defined. Particular in relation to 'insert' and
+-- 'delete'.
+--
+
+-- |
+-- API changes from xmonad 0.1:
+-- StackSet constructor arguments changed. StackSet workspace window screen
+--
+-- * new,                    -- was: empty
+--
+-- * view,
+--
+-- * index,
+--
+-- * peek,                   -- was: peek\/peekStack
+--
+-- * focusUp, focusDown,  -- was: rotate
+--
+-- * swapUp, swapDown
+--
+-- * focus                   -- was: raiseFocus
+--
+-- * insertUp,             -- was: insert\/push
+--
+-- * delete,
+--
+-- * swapMaster,             -- was: promote\/swap
+--
+-- * member,
+--
+-- * shift,
+--
+-- * lookupWorkspace,        -- was: workspace
+--
+-- * visibleWorkspaces       -- gone.
+--
+------------------------------------------------------------------------
+-- |
+-- A cursor into a non-empty list of workspaces.
+--
+-- We puncture the workspace list, producing a hole in the structure
+-- used to track the currently focused workspace. The two other lists
+-- that are produced are used to track those workspaces visible as
+-- Xinerama screens, and those workspaces not visible anywhere.
+
+data StackSet i l a sid sd =
+    StackSet { current  :: !(Screen i l a sid sd)    -- ^ currently focused workspace
+             , visible  :: [Screen i l a sid sd]     -- ^ non-focused workspaces, visible in xinerama
+             , hidden   :: [Workspace i l a]      -- ^ workspaces not visible anywhere
+             , floating :: M.Map a RationalRect -- ^ floating windows
+             } deriving (Show, Read, Eq)
+
+-- | Visible workspaces, and their Xinerama screens.
+data Screen i l a sid sd = Screen { workspace :: !(Workspace i l a)
+                                  , screen :: !sid
+                                  , screenDetail :: !sd }
+    deriving (Show, Read, Eq)
+
+-- |
+-- A workspace is just a tag - its index - and a stack
+--
+data Workspace i l a = Workspace  { tag :: !i, layout :: l, stack :: StackOrNot a }
+    deriving (Show, Read, Eq)
+
+-- | A structure for window geometries
+data RationalRect = RationalRect Rational Rational Rational Rational
+    deriving (Show, Read, Eq)
+
+-- |
+-- A stack is a cursor onto a (possibly empty) window list.
+-- The data structure tracks focus by construction, and
+-- the master window is by convention the top-most item.
+-- Focus operations will not reorder the list that results from
+-- flattening the cursor. The structure can be envisaged as:
+--
+-- >    +-- master:  < '7' >
+-- > up |            [ '2' ]
+-- >    +---------   [ '3' ]
+-- > focus:          < '4' >
+-- > dn +----------- [ '8' ]
+--
+-- A 'Stack' can be viewed as a list with a hole punched in it to make
+-- the focused position. Under the zipper\/calculus view of such
+-- structures, it is the differentiation of a [a], and integrating it
+-- back has a natural implementation used in 'index'.
+--
+type StackOrNot a = Maybe (Stack a)
+
+data Stack a = Stack { focus  :: !a        -- focused thing in this set
+                     , up     :: [a]       -- clowns to the left
+                     , down   :: [a] }     -- jokers to the right
+    deriving (Show, Read, Eq)
+
+
+-- | this function indicates to catch that an error is expected
+abort :: String -> a
+abort x = error $ "xmonad: StackSet: " ++ x
+
+-- ---------------------------------------------------------------------
+-- $construction
+
+-- | /O(n)/. Create a new stackset, of empty stacks, with given tags, with
+-- 'm' physical screens. 'm' should be less than or equal to the number of
+-- workspace tags.  The first workspace in the list will be current.
+--
+-- Xinerama: Virtual workspaces are assigned to physical screens, starting at 0.
+--
+new :: (Integral s) => l -> [i] -> [sd] -> StackSet i l a s sd
+new l wids m | not (null wids) && length m <= length wids = StackSet cur visi unseen M.empty
+  where (seen,unseen) = L.splitAt (length m) $ map (\i -> Workspace i l Nothing) wids
+        (cur:visi)    = [ Screen i s sd |  (i, s, sd) <- zip3 seen [0..] m ]
+                -- now zip up visibles with their screen id
+new _ _ _ = abort "non-positive argument to StackSet.new"
+
+-- |
+-- /O(w)/. Set focus to the workspace with index \'i\'.
+-- If the index is out of range, return the original StackSet.
+--
+-- Xinerama: If the workspace is not visible on any Xinerama screen, it
+-- becomes the current screen. If it is in the visible list, it becomes
+-- current.
+
+view :: (Eq s, Eq i) => i -> StackSet i l a s sd -> StackSet i l a s sd
+view i s
+    | not (i `tagMember` s)
+      || i == tag (workspace (current s)) = s  -- out of bounds or current
+
+    | Just x <- L.find ((i==).tag.workspace) (visible s)
+    -- if it is visible, it is just raised
+    = s { current = x, visible = current s : L.deleteBy (equating screen) x (visible s) }
+
+    | Just x <- L.find ((i==).tag)           (hidden  s) -- must be hidden then
+    -- if it was hidden, it is raised on the xine screen currently used
+    = s { current = (current s) { workspace = x }
+        , hidden = workspace (current s) : L.deleteBy (equating tag) x (hidden s) }
+
+    | otherwise = s -- can't happen: all workspaces are either invalid, current, visible, or hidden
+
+  where equating f = \x y -> f x == f y
+
+    -- 'Catch'ing this might be hard. Relies on monotonically increasing
+    -- workspace tags defined in 'new'
+    --
+    -- and now tags are not monotonic, what happens here?
+
+-- |
+-- Set focus to the given workspace.  If that workspace does not exist
+-- in the stackset, the original workspace is returned.  If that workspace is
+-- 'hidden', then display that workspace on the current screen, and move the
+-- current workspace to 'hidden'.  If that workspace is 'visible' on another
+-- screen, the workspaces of the current screen and the other screen are
+-- swapped.
+
+greedyView :: (Eq s, Eq i) => i -> StackSet i l a s sd -> StackSet i l a s sd
+greedyView w ws
+     | any wTag (hidden ws) = view w ws
+     | (Just s) <- L.find (wTag . workspace) (visible ws)
+                            = ws { current = (current ws) { workspace = workspace s }
+                                 , visible = s { workspace = workspace (current ws) }
+                                           : L.filter (not . wTag . workspace) (visible ws) }
+     | otherwise = ws
+   where wTag = (w == ) . tag
+
+-- ---------------------------------------------------------------------
+-- $xinerama
+
+-- | Find the tag of the workspace visible on Xinerama screen 'sc'.
+-- Nothing if screen is out of bounds.
+lookupWorkspace :: Eq s => s -> StackSet i l a s sd -> Maybe i
+lookupWorkspace sc w = listToMaybe [ tag i | Screen i s _ <- current w : visible w, s == sc ]
+
+-- ---------------------------------------------------------------------
+-- $stackOperations
+
+-- |
+-- The 'with' function takes a default value, a function, and a
+-- StackSet. If the current stack is Nothing, 'with' returns the
+-- default value. Otherwise, it applies the function to the stack,
+-- returning the result. It is like 'maybe' for the focused workspace.
+--
+with :: b -> (Stack a -> b) -> StackSet i l a s sd -> b
+with dflt f = maybe dflt f . stack . workspace . current
+
+-- |
+-- Apply a function, and a default value for Nothing, to modify the current stack.
+--
+modify :: StackOrNot a -> (Stack a -> StackOrNot a) -> StackSet i l a s sd -> StackSet i l a s sd
+modify d f s = s { current = (current s)
+                        { workspace = (workspace (current s)) { stack = with d f s }}}
+
+-- |
+-- Apply a function to modify the current stack if it isn't empty, and we don't
+--  want to empty it.
+--
+modify' :: (Stack a -> Stack a) -> StackSet i l a s sd -> StackSet i l a s sd
+modify' f = modify Nothing (Just . f)
+
+-- |
+-- /O(1)/. Extract the focused element of the current stack.
+-- Return Just that element, or Nothing for an empty stack.
+--
+peek :: StackSet i l a s sd -> Maybe a
+peek = with Nothing (return . focus)
+
+-- |
+-- /O(n)/. Flatten a Stack into a list.
+--
+integrate :: Stack a -> [a]
+integrate (Stack x l r) = reverse l ++ x : r
+
+-- |
+-- /O(n)/ Flatten a possibly empty stack into a list.
+integrate' :: StackOrNot a -> [a]
+integrate' = maybe [] integrate
+
+-- |
+-- /O(n)/. Texture a list.
+--
+differentiate :: [a] -> StackOrNot a
+differentiate []     = Nothing
+differentiate (x:xs) = Just $ Stack x [] xs
+
+-- |
+-- /O(n)/. 'filter p s' returns the elements of 's' such that 'p' evaluates to
+-- True.  Order is preserved, and focus moves as described for 'delete'.
+--
+filter :: (a -> Bool) -> Stack a -> StackOrNot a
+filter p (Stack f ls rs) = case L.filter p (f:rs) of
+    f':rs' -> Just $ Stack f' (L.filter p ls) rs'    -- maybe move focus down
+    []     -> case L.filter p ls of                  -- filter back up
+                    f':ls' -> Just $ Stack f' ls' [] -- else up
+                    []     -> Nothing
+
+-- |
+-- /O(s)/. Extract the stack on the current workspace, as a list.
+-- The order of the stack is determined by the master window -- it will be
+-- the head of the list. The implementation is given by the natural
+-- integration of a one-hole list cursor, back to a list.
+--
+index :: StackSet i l a s sd -> [a]
+index = with [] integrate
+
+--  let is = t : r ++ reverse l in take (length is) (dropWhile (/= m) (cycle is))
+
+-- |
+-- /O(1), O(w) on the wrapping case/.
+--
+-- focusUp, focusDown. Move the window focus up or down the stack,
+-- wrapping if we reach the end. The wrapping should model a 'cycle'
+-- on the current stack. The 'master' window, and window order,
+-- are unaffected by movement of focus.
+--
+-- swapUp, swapDown, swap the neighbour in the stack ordering, wrapping
+-- if we reach the end. Again the wrapping model should 'cycle' on
+-- the current stack.
+--
+focusUp, focusDown, swapUp, swapDown :: StackSet i l a s sd -> StackSet i l a s sd
+focusUp   = modify' focusUp'
+focusDown = modify' (reverseStack . focusUp' . reverseStack)
+
+swapUp    = modify' swapUp'
+swapDown  = modify' (reverseStack . swapUp' . reverseStack)
+
+focusUp', swapUp' :: Stack a -> Stack a
+focusUp' (Stack t (l:ls) rs) = Stack l ls (t:rs)
+focusUp' (Stack t []     rs) = Stack x xs [] where (x:xs) = reverse (t:rs)
+
+swapUp'  (Stack t (l:ls) rs) = Stack t ls (l:rs)
+swapUp'  (Stack t []     rs) = Stack t (reverse rs) []
+
+-- | reverse a stack: up becomes down and down becomes up.
+reverseStack :: Stack a -> Stack a
+reverseStack (Stack t ls rs) = Stack t rs ls
+
+--
+-- | /O(1) on current window, O(n) in general/. Focus the window 'w',
+-- and set its workspace as current.
+--
+focusWindow :: (Eq s, Eq a, Eq i) => a -> StackSet i l a s sd -> StackSet i l a s sd
+focusWindow w s | Just w == peek s = s
+                | otherwise        = maybe s id $ do
+                    n <- findIndex w s
+                    return $ until ((Just w ==) . peek) focusUp (view n s)
+
+-- | Get a list of all screens in the StackSet.
+screens :: StackSet i l a s sd -> [Screen i l a s sd]
+screens s = current s : visible s
+
+-- | Get a list of all workspaces in the StackSet.
+workspaces :: StackSet i l a s sd -> [Workspace i l a]
+workspaces s = workspace (current s) : map workspace (visible s) ++ hidden s
+
+-- | Get a list of all windows in the StackSet in no particular order
+allWindows :: Eq a => StackSet i l a s sd -> [a]
+allWindows = L.nub . concatMap (integrate' . stack) . workspaces
+
+-- | Is the given tag present in the StackSet?
+tagMember :: Eq i => i -> StackSet i l a s sd -> Bool
+tagMember t = elem t . map tag . workspaces
+
+-- | Rename a given tag if present in the StackSet.
+renameTag :: Eq i => i -> i -> StackSet i l a s sd -> StackSet i l a s sd
+renameTag o n = mapWorkspace rename
+    where rename w = if tag w == o then w { tag = n } else w
+
+-- | Ensure that a given set of tags is present.
+ensureTags :: Eq i => l -> [i] -> StackSet i l a s sd -> StackSet i l a s sd
+ensureTags l allt st = et allt (map tag (workspaces st) \\ allt) st
+    where et [] _ s = s
+          et (i:is) rn s | i `tagMember` s = et is rn s
+          et (i:is) [] s = et is [] (s { hidden = Workspace i l Nothing : hidden s })
+          et (i:is) (r:rs) s = et is rs $ renameTag r i s
+
+-- | Map a function on all the workspaces in the StackSet.
+mapWorkspace :: (Workspace i l a -> Workspace i l a) -> StackSet i l a s sd -> StackSet i l a s sd
+mapWorkspace f s = s { current = updScr (current s)
+                     , visible = map updScr (visible s)
+                     , hidden  = map f (hidden s) }
+    where updScr scr = scr { workspace = f (workspace scr) }
+
+-- | Map a function on all the layouts in the StackSet.
+mapLayout :: (l -> l') -> StackSet i l a s sd -> StackSet i l' a s sd
+mapLayout f (StackSet v vs hs m) = StackSet (fScreen v) (map fScreen vs) (map fWorkspace hs) m
+ where
+    fScreen (Screen ws s sd) = Screen (fWorkspace ws) s sd
+    fWorkspace (Workspace t l s) = Workspace t (f l) s
+
+-- | /O(n)/. Is a window in the StackSet.
+member :: Eq a => a -> StackSet i l a s sd -> Bool
+member a s = maybe False (const True) (findIndex a s)
+
+-- | /O(1) on current window, O(n) in general/.
+-- Return Just the workspace index of the given window, or Nothing
+-- if the window is not in the StackSet.
+findIndex :: Eq a => a -> StackSet i l a s sd -> Maybe i
+findIndex a s = listToMaybe
+    [ tag w | w <- workspaces s, has a (stack w) ]
+    where has _ Nothing         = False
+          has x (Just (Stack t l r)) = x `elem` (t : l ++ r)
+
+-- ---------------------------------------------------------------------
+-- $modifyStackset
+
+-- |
+-- /O(n)/. (Complexity due to duplicate check). Insert a new element into
+-- the stack, above the currently focused element.
+--
+-- The new element is given focus, and is set as the master window.
+-- The previously focused element is moved down.  The previously
+-- 'master' element is forgotten. (Thus, 'insert' will cause a retiling).
+--
+-- If the element is already in the stackset, the original stackset is
+-- returned unmodified.
+--
+-- Semantics in Huet's paper is that insert doesn't move the cursor.
+-- However, we choose to insert above, and move the focus.
+--
+insertUp :: Eq a => a -> StackSet i l a s sd -> StackSet i l a s sd
+insertUp a s = if member a s then s else insert
+  where insert = modify (Just $ Stack a [] []) (\(Stack t l r) -> Just $ Stack a l (t:r)) s
+
+-- insertDown :: a -> StackSet i l a s sd -> StackSet i l a s sd
+-- insertDown a = modify (Stack a [] []) $ \(Stack t l r) -> Stack a (t:l) r
+-- Old semantics, from Huet.
+-- >    w { down = a : down w }
+
+-- |
+-- /O(1) on current window, O(n) in general/. Delete window 'w' if it exists.
+-- There are 4 cases to consider:
+--
+--   * delete on an Nothing workspace leaves it Nothing
+--   * otherwise, try to move focus to the down
+--   * otherwise, try to move focus to the up
+--   * otherwise, you've got an empty workspace, becomes Nothing
+--
+-- Behaviour with respect to the master:
+--
+--   * deleting the master window resets it to the newly focused window
+--   * otherwise, delete doesn't affect the master.
+--
+delete :: (Ord a, Eq s) => a -> StackSet i l a s sd -> StackSet i l a s sd
+delete w = sink w . delete' w
+
+-- | Only temporarily remove the window from the stack, thereby not destroying special
+-- information saved in the Stackset
+delete' :: (Eq a, Eq s) => a -> StackSet i l a s sd -> StackSet i l a s sd
+delete' w s = s { current = removeFromScreen        (current s)
+                , visible = map removeFromScreen    (visible s)
+                , hidden  = map removeFromWorkspace (hidden  s) }
+    where removeFromWorkspace ws = ws { stack = stack ws >>= filter (/=w) }
+          removeFromScreen scr   = scr { workspace = removeFromWorkspace (workspace scr) }
 
 ------------------------------------------------------------------------
 
--- | The StackSet data structure. Multiple screens containing tables of
--- stacks, with a current pointer
-data StackSet i j a =
-    StackSet
-        { current  :: !i             -- ^ the currently visible stack
-        , screen2ws:: !(M.Map j i)   -- ^ screen -> workspace
-        , ws2screen:: !(M.Map i j)   -- ^ workspace -> screen map
-        , stacks   :: !(M.Map i [a]) -- ^ the separate stacks
-        , focus    :: !(M.Map i a)   -- ^ the window focused in each stack
-        , cache    :: !(M.Map a i)   -- ^ a cache of windows back to their stacks
-        } deriving Eq
+-- | Given a window, and its preferred rectangle, set it as floating
+-- A floating window should already be managed by the StackSet.
+float :: Ord a => a -> RationalRect -> StackSet i l a s sd -> StackSet i l a s sd
+float w r s = s { floating = M.insert w r (floating s) }
 
-instance (Show i, Show a) => Show (StackSet i j a) where
-    showsPrec p s r = showsPrec p (show . toList $ s) r
-
--- The cache is used to check on insertion that we don't already have
--- this window managed on another stack
+-- | Clear the floating status of a window
+sink :: Ord a => a -> StackSet i l a s sd -> StackSet i l a s sd
+sink w s = s { floating = M.delete w (floating s) }
 
 ------------------------------------------------------------------------
+-- $settingMW
 
--- | /O(n)/. Create a new empty stacks of size 'n', indexed from 0, with 'm'
--- screens. (also indexed from 0) The 0-indexed stack will be current.
-empty :: (Integral i, Integral j) => Int -> Int -> StackSet i j a
-empty n m = StackSet { current   = 0
-                     , screen2ws = wsScrs2Works
-                     , ws2screen = wsWorks2Scrs
-                     , stacks    = M.fromList (zip [0..fromIntegral n-1] (repeat []))
-                     , focus     = M.empty
-                     , cache     = M.empty }
+-- | /O(s)/. Set the master window to the focused window.
+-- The old master window is swapped in the tiling order with the focused window.
+-- Focus stays with the item moved.
+swapMaster :: StackSet i l a s sd -> StackSet i l a s sd
+swapMaster = modify' $ \c -> case c of
+    Stack _ [] _  -> c    -- already master.
+    Stack t ls rs -> Stack t [] (xs ++ x : rs) where (x:xs) = reverse ls
 
-    where (scrs,wrks)  = unzip $ map (\x -> (fromIntegral x, fromIntegral x)) [0..m-1]
-          wsScrs2Works = M.fromList (zip scrs wrks)
-          wsWorks2Scrs = M.fromList (zip wrks scrs)
+-- natural! keep focus, move current to the top, move top to current.
 
--- | /O(log w)/. True if x is somewhere in the StackSet
-member :: Ord a => a -> StackSet i j a -> Bool
-member a w = M.member a (cache w)
-
--- | /O(log n)/. Looks up the workspace that x is in, if it is in the StackSet
--- lookup :: (Monad m, Ord a) => a -> StackSet i j a -> m i
--- lookup x w = M.lookup x (cache w)
-
--- | /O(n)/. Number of stacks
-size :: StackSet i j a -> Int
-size = M.size . stacks
-
-------------------------------------------------------------------------
-
--- | fromList. Build a new StackSet from a list of list of elements,
--- keeping track of the currently focused workspace, and the total
--- number of workspaces. If there are duplicates in the list, the last
--- occurence wins.
-fromList :: (Integral i, Integral j, Ord a) => (i, Int,[[a]]) -> StackSet i j a
-fromList (_,_,[]) = error "Cannot build a StackSet from an empty list"
-
-fromList (n,m,xs) | n < 0 || n >= L.genericLength xs
-                = error $ "Cursor index is out of range: " ++ show (n, length xs)
-                  | m < 1 || m >  L.genericLength xs
-                = error $ "Can't have more screens than workspaces: " ++ show (m, length xs)
-
-fromList (o,m,xs) = view o $ foldr (\(i,ys) s ->
-                                  foldr (\a t -> insert a i t) s ys)
-                                      (empty (length xs) m) (zip [0..] xs)
-
-
--- | toList. Flatten a stackset to a list of lists
-toList  :: StackSet i j a -> (i,Int,[[a]])
-toList x = (current x, M.size $ screen2ws x, map snd $ M.toList (stacks x))
-
--- | Push. Insert an element onto the top of the current stack.
--- If the element is already in the current stack, it is moved to the top.
--- If the element is managed on another stack, it is removed from that
--- stack first.
-push :: (Integral i, Ord a) => a -> StackSet i j a -> StackSet i j a
-push k w = insert k (current w) w
-
--- | /O(log s)/. Extract the element on the top of the current stack. If no such
--- element exists, Nothing is returned.
-peek :: Integral i => StackSet i j a -> Maybe a
-peek w = peekStack (current w) w
-
--- | /O(log s)/. Extract the element on the top of the given stack. If no such
--- element exists, Nothing is returned.
-peekStack :: Integral i => i -> StackSet i j a -> Maybe a
-peekStack i w = M.lookup i (focus w)
-
--- | /O(log s)/. Index. Extract the stack at workspace 'n'.
--- If the index is invalid, an exception is thrown.
-index :: Integral i => i -> StackSet i j a -> [a]
-index k w = fromJust (M.lookup k (stacks w))
-
--- | view. Set the stack specified by the argument as being visible and the
--- current StackSet. If the stack wasn't previously visible, it will become
--- visible on the current screen. If the index is out of range an exception is
--- thrown.
-view :: (Integral i, Integral j) => i -> StackSet i j a -> StackSet i j a
--- view n w | n >= 0 && n < fromIntegral (M.size (stacks w)) -- coerce
-
-view n w | M.member n (stacks w)
-         = if M.member n (ws2screen w) then w { current = n }
-                                       else tweak (fromJust $ screen (current w) w)
-         | otherwise = error $ "view: index out of bounds: " ++ show n
-  where
-    tweak sc = w { screen2ws = M.insert sc n (screen2ws w)
-                 , ws2screen = M.insert n sc (M.filter (/=sc) (ws2screen w))
-                 , current = n
-                 }
-
--- | That screen that workspace 'n' is visible on, if any.
-screen :: Integral i => i -> StackSet i j a -> Maybe j
-screen n w = M.lookup n (ws2screen w)
-
--- | The workspace visible on screen 'sc'. Nothing if screen is out of bounds.
-workspace :: Integral j => j -> StackSet i j a -> Maybe i
-workspace sc w = M.lookup sc (screen2ws w)
-
--- | A list of the currently visible workspaces.
-visibleWorkspaces :: StackSet i j a -> [i]
-visibleWorkspaces = M.keys . ws2screen
+-- | /O(s)/. Set focus to the master window.
+focusMaster :: StackSet i l a s sd -> StackSet i l a s sd
+focusMaster = modify' $ \c -> case c of
+    Stack _ [] _  -> c
+    Stack t ls rs -> Stack x [] (xs ++ t : rs) where (x:xs) = reverse ls
 
 --
--- | /O(log n)/. rotate. cycle the current window list up or down.
--- Has the effect of rotating focus. In fullscreen mode this will cause
--- a new window to be visible.
---
---  rotate EQ   -->  [5,6,7,8,1,2,3,4]
---  rotate GT   -->  [6,7,8,1,2,3,4,5]
---  rotate LT   -->  [4,5,6,7,8,1,2,3]
---
---  where xs = [5..8] ++ [1..4]
---
-rotate :: (Integral i, Eq a) => Ordering -> StackSet i j a -> StackSet i j a
-rotate o w = maybe w id $ do
-    f <- M.lookup (current w) (focus w)
-    s <- M.lookup (current w) (stacks w)
-    ea <- case o of
-            EQ -> Nothing
-            GT -> elemAfter f s
-            LT -> elemAfter f (reverse s)
-    return $ w { focus = M.insert (current w) ea (focus w) }
+-- ---------------------------------------------------------------------
+-- $composite
 
--- | /O(log n)/. shift. move the client on top of the current stack to
--- the top of stack 'n'. If the stack to move to is not valid, and
--- exception is thrown.
+-- | /O(w)/. shift. Move the focused element of the current stack to stack
+-- 'n', leaving it as the focused element on that stack. The item is
+-- inserted above the currently focused element on that workspace.
+-- The actual focused workspace doesn't change. If there is no
+-- element on the current stack, the original stackSet is returned.
 --
-shift :: (Integral i, Ord a) => i -> StackSet i j a -> StackSet i j a
-shift n w = maybe w (\k -> insert k n (delete k w)) (peek w)
+shift :: (Ord a, Eq s, Eq i) => i -> StackSet i l a s sd -> StackSet i l a s sd
+shift n s | n `tagMember` s && n /= curtag = maybe s go (peek s)
+          | otherwise                      = s
+    where go w = view curtag . insertUp w . view n . delete' w $ s
+          curtag = tag (workspace (current s))
 
--- | /O(log n)/. Insert an element onto the top of stack 'n'.
--- If the element is already in the stack 'n', it is moved to the top.
--- If the element exists on another stack, it is removed from that stack.
--- If the index is wrong an exception is thrown.
---
-insert :: (Integral i, Ord a) => a -> i -> StackSet i j a -> StackSet i j a
-insert k n old = new { cache  = M.insert k n (cache new)
-                     , stacks = M.adjust (k:) n (stacks new)
-                     , focus  = M.insert n k (focus new) }
-    where new = delete k old
+-- | /O(n)/. shiftWin. Searches for the specified window 'w' on all workspaces
+-- of the stackSet and moves it to stack 'n', leaving it as the focused
+-- element on that stack. The item is inserted above the currently
+-- focused element on that workspace.
+-- The actual focused workspace doesn't change. If the window is not
+-- found in the stackSet, the original stackSet is returned.
+-- TODO how does this duplicate 'shift's behaviour?
+shiftWin :: (Ord a, Eq a, Eq s, Eq i) => i -> a -> StackSet i l a s sd -> StackSet i l a s sd
+shiftWin n w s | from == Nothing                     = s -- not found
+               | n `tagMember` s && (Just n) /= from = go
+               | otherwise                           = s
+    where from   = findIndex w s
 
--- | /O(log n)/. Delete an element entirely from from the StackSet.
--- This can be used to ensure that a given element is not managed elsewhere.
--- If the element doesn't exist, the original StackSet is returned unmodified.
-delete :: (Integral i, Ord a) => a -> StackSet i j a -> StackSet i j a
-delete k w = maybe w tweak (M.lookup k (cache w))
-  where
-    tweak i = w { cache  = M.delete k (cache w)
-                , stacks = M.adjust (L.delete k) i (stacks w)
-                , focus  = M.update (\k' -> if k == k' then elemAfter k (stacks w M.! i)
-                                                       else Just k') i
-                                    (focus w)
-                }
+          go     = on n (insertUp w) . on (fromJust from) (delete' w) $ s
+          curtag = tag (workspace (current s))
+          on i f = view curtag . f . view i
 
--- | /O(log n)/. If the given window is contained in a workspace, make it the
--- focused window of that workspace, and make that workspace the current one.
-raiseFocus :: (Integral i, Integral j, Ord a) => a -> StackSet i j a -> StackSet i j a
-raiseFocus k w = case M.lookup k (cache w) of
-    Nothing -> w
-    Just i  -> (view i w) { focus = M.insert i k (focus w) }
-
--- | Swap the currently focused window with the master window (the
--- window on top of the stack). Focus moves to the master.
-promote :: (Integral i, Ord a) => StackSet i j a -> StackSet i j a
-promote w = maybe w id $ do
-    a <- peek w -- fail if null
-    let w' = w { stacks = M.adjust (\s -> swap a (head s) s) (current w) (stacks w) }
-    return $ insert a (current w) w' -- and maintain focus (?)
-
---
--- | Swap first occurences of 'a' and 'b' in list.
--- If both elements are not in the list, the list is unchanged.
---
--- Given a set as a list (no duplicates)
---
--- > swap a b . swap a b == id
---
-swap :: Eq a => a -> a -> [a] -> [a]
-swap a b xs
-    | a == b                    = xs    -- do nothing
-    | Just ai <- L.elemIndex a xs
-    , Just bi <- L.elemIndex b xs = insertAt bi a (insertAt ai b xs)
- where
-    insertAt n x ys = as ++ x : tail bs
-        where (as,bs) = splitAt n ys
-
-swap _ _ xs = xs -- do nothing
-
---
--- cycling:
--- promote w = w { stacks = M.adjust next (current w) (stacks w) }
---    where next [] = []
---          next xs = last xs : init xs
---
-
--- | Find the element in the (circular) list after given element.
-elemAfter :: Eq a => a -> [a] -> Maybe a
-elemAfter w ws = listToMaybe . filter (/= w) . dropWhile (/= w) $ ws ++ ws

TODO

@@ -1,29 +1,15 @@
-- think about the statusbar/multithreading.
-    Three shared TVars:
-        windowTitle :: TVar String
-        workspace   :: TVar Int
-        statusText  :: TVar String
-    Three threads:
-        Main thread, handles all of the events that it handles now.  When
-        necessary, it writes to workspace or windowTitle
+ - Write down invariants for the window life cycle, especially:
+    - When are borders set?  Prove that the current handling is sufficient.
 
-        Status IO thread, the algorithm is something like this:
-            forever $ do
-                s <- getLine
-                atomic (writeTVar statusText s)
+= Release management =
 
-        Statusbar drawing thread, waits for changes in all three TVars, and
-        redraws whenever it finds a change.
-
-- Notes on new StackSet:
-
-   The actors: screens, workspaces, windows
-
-   Invariants:
-   - There is exactly one screen in focus at any given time.
-   - A screen views exactly one workspace.
-   - A workspace is visible on one or zero screens.
-   - A workspace has zero or more windows.
-   - A workspace has either one or zero windows in focus.  Zero if the
-     workspace has no windows, one in all other cases.
-   - A window is a member of only one workspace.
+* build and typecheck all XMC
+* generate haddocks for core and XMC, upload to xmonad.org
+* generate manpage, generate html manpage
+* document, with photos, any new layouts
+* double check README build instructions
+* test core with 6.6 and 6.8
+* upload X11/X11-extras/xmonad to hacakge
+* check examples/text in use-facing Config.hs
+* check tour.html and intro.html are up to date, and mention all core bindings
+* bump xmonad.cabal version

XMonad.hs

@@ -1,4 +1,5 @@
-{-# OPTIONS -fglasgow-exts #-}
+{-# LANGUAGE ExistentialQuantification, FlexibleInstances, GeneralizedNewtypeDeriving, MultiParamTypeClasses #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.hs
@@ -9,113 +10,266 @@
 -- Stability   :  unstable
 -- Portability :  not portable, uses cunning newtype deriving
 --
------------------------------------------------------------------------------
---
 -- The X monad, a state monad transformer over IO, for the window
 -- manager state, and support routines.
 --
+-----------------------------------------------------------------------------
 
 module XMonad (
-    X, WindowSet, WorkspaceId(..), ScreenId(..), XState(..), Layout(..), LayoutDesc(..),
-    runX, io, withDisplay, isRoot, spawn, trace, whenJust, rotateLayout
+    X, WindowSet, WindowSpace, WorkspaceId, ScreenId(..), ScreenDetail(..), XState(..), XConf(..), LayoutClass(..), Layout(..), ReadableLayout(..),
+    Typeable, Message, SomeMessage(..), fromMessage, runLayout,
+    runX, catchX, userCode, io, catchIO, withDisplay, withWindowSet, isRoot, getAtom, spawn, restart, trace, whenJust, whenX,
+    atom_WM_STATE, atom_WM_PROTOCOLS, atom_WM_DELETE_WINDOW
   ) where
 
-import StackSet (StackSet)
+import StackSet
 
+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)
+import System.Posix.Process (executeFile, forkProcess, getProcessStatus, createSession)
 import System.Exit
+import System.Environment
 import Graphics.X11.Xlib
+-- for Read instance
+import Graphics.X11.Xlib.Extras ()
+import Data.Typeable
 
 import qualified Data.Map as M
+import qualified Data.Set as S
 
 -- | XState, the window manager state.
 -- Just the display, width, height and a window list
 data XState = XState
+    { windowset    :: !WindowSet           -- ^ workspace list
+    , mapped       :: !(S.Set Window)      -- ^ the Set of mapped windows
+    , waitingUnmap :: !(M.Map Window Int)  -- ^ the number of expected UnmapEvents
+    , dragging     :: !(Maybe (Position -> Position -> X (), X ())) }
+data XConf = XConf
     { display       :: Display      -- ^ the X11 display
-
     , theRoot       :: !Window      -- ^ the root window
-    , wmdelete          :: !Atom                           -- ^ window deletion atom
-    , wmprotocols       :: !Atom                           -- ^ wm protocols atom
-    , dimensions        :: !(Int,Int)                      -- ^ dimensions of the screen, 
-                                                           -- used for hiding windows
-    , workspace         :: !WindowSet                      -- ^ workspace list
+    , normalBorder  :: !Pixel       -- ^ border color of unfocused windows
+    , focusedBorder :: !Pixel     } -- ^ border color of the focused window
 
-    , xineScreens       :: ![Rectangle]                    -- ^ dimensions of each screen
-    , defaultLayoutDesc :: !LayoutDesc                     -- ^ default layout
-    , layoutDescs       :: !(M.Map WorkspaceId LayoutDesc) -- ^ mapping of workspaces 
-                                                           -- to descriptions of their layouts
-    }
-
-type WindowSet = StackSet WorkspaceId ScreenId Window
+type WindowSet   = StackSet  WorkspaceId (Layout Window) Window ScreenId ScreenDetail
+type WindowSpace = Workspace WorkspaceId (Layout Window) Window
 
 -- | Virtual workspace indicies
-newtype WorkspaceId = W Int deriving (Eq,Ord,Show,Enum,Num,Integral,Real)
+type WorkspaceId = String
 
 -- | Physical screen indicies
-newtype ScreenId    = S Int deriving (Eq,Ord,Show,Enum,Num,Integral,Real)
+newtype ScreenId    = S Int deriving (Eq,Ord,Show,Read,Enum,Num,Integral,Real)
+
+-- | TODO Comment me
+data ScreenDetail   = SD { screenRect :: !Rectangle
+                         , statusGap  :: !(Int,Int,Int,Int) -- ^ width of status bar on the screen
+                         } deriving (Eq,Show, Read)
 
 ------------------------------------------------------------------------
 
 -- | The X monad, a StateT transformer over IO encapsulating the window
 -- manager state
-newtype X a = X (StateT XState IO a)
-    deriving (Functor, Monad, MonadIO, MonadState XState)
+--
+-- Dynamic components may be retrieved with 'get', static components
+-- with 'ask'. With newtype deriving we get readers and state monads
+-- instantiated on XConf and XState automatically.
+--
+newtype X a = X (ReaderT XConf (StateT XState IO) a)
+    deriving (Functor, Monad, MonadIO, MonadState XState, MonadReader XConf)
 
 -- | Run the X monad, given a chunk of X monad code, and an initial state
 -- Return the result, and final state
-runX :: XState -> X a -> IO ()
-runX st (X a) = runStateT a st >> return ()
+runX :: XConf -> XState -> X a -> IO (a, XState)
+runX c st (X a) = runStateT (runReaderT a c) st
+
+-- | Run in the X monad, and in case of exception, and catch it and log it
+-- to stderr, and run the error case.
+catchX :: X a -> X a -> X a
+catchX job errcase = do
+    st <- get
+    c <- ask
+    (a, s') <- io $ runX c st job `catch`
+                    \e -> case e of
+                            ExitException {} -> throw e
+                            _ -> do hPrint stderr e; runX c st errcase
+    put s'
+    return a
+
+-- | Execute the argument, catching all exceptions.  Either this function or
+-- catchX should be used at all callsites of user customized code.
+userCode :: X () -> X ()
+userCode a = catchX (a >> return ()) (return ())
 
 -- ---------------------------------------------------------------------
 -- Convenient wrappers to state
 
 -- | Run a monad action with the current display settings
-withDisplay :: (Display -> X ()) -> X ()
-withDisplay f = gets display >>= f
+withDisplay :: (Display -> X a) -> X a
+withDisplay   f = asks display >>= f
+
+-- | Run a monadic action with the current stack set
+withWindowSet :: (WindowSet -> X a) -> X a
+withWindowSet f = gets windowset >>= f
 
 -- | True if the given window is the root window
 isRoot :: Window -> X Bool
-isRoot w = liftM (w==) (gets theRoot)
+isRoot w = liftM (w==) (asks theRoot)
+
+-- | Wrapper for the common case of atom internment
+getAtom :: String -> X Atom
+getAtom str = withDisplay $ \dpy -> io $ internAtom dpy str False
+
+-- | Common non-predefined atoms
+atom_WM_PROTOCOLS, atom_WM_DELETE_WINDOW, atom_WM_STATE :: X Atom
+atom_WM_PROTOCOLS       = getAtom "WM_PROTOCOLS"
+atom_WM_DELETE_WINDOW   = getAtom "WM_DELETE_WINDOW"
+atom_WM_STATE           = getAtom "WM_STATE"
 
 ------------------------------------------------------------------------
--- Layout handling
+-- | LayoutClass handling. See particular instances in Operations.hs
+
+-- | 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 existentially wrapped Layout.
+class ReadableLayout a where
+    readTypes :: [Layout a]
 
 -- | The different layout modes
-data Layout = Full | Tall | Wide deriving (Enum, Bounded, Eq)
+--
+-- '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
 
--- | 'rot' for Layout.
-rotateLayout :: Layout -> Layout
-rotateLayout x = if x == maxBound then minBound else succ x
+    -- | Given a Rectangle in which to place the windows, and a Stack of
+    -- windows, return a list of windows and their corresponding Rectangles.
+    -- The order of windows in this list should be the desired stacking order.
+    -- Also return a modified layout, if this layout needs to be modified
+    -- (e.g. if we keep track of the windows we have displayed).
+    doLayout    :: layout a -> Rectangle -> Stack a -> X ([(a, Rectangle)], Maybe (layout a))
+    doLayout l r s   = return (pureLayout l r s, Nothing)
 
--- | A full description of a particular workspace's layout parameters.
-data LayoutDesc = LayoutDesc { layoutType   :: !Layout
-                             , tileFraction :: !Rational
-                             }
+    -- | This is a pure version of doLayout, for cases where we don't need
+    -- access to the X monad to determine how to layou out the windows, and
+    -- we don't need to modify our layout itself.
+    pureLayout  :: layout a -> Rectangle -> Stack a -> [(a, Rectangle)]
+    pureLayout _ r s = [(focus s, r)]
+
+    -- | 'handleMessage' performs message handling for that layout.  If
+    -- 'handleMessage' returns Nothing, then the layout did not respond to
+    -- that message and the screen is not refreshed.  Otherwise, 'handleMessage'
+    -- returns an updated 'LayoutClass' and the screen is refreshed.
+    --
+    handleMessage :: layout a -> SomeMessage -> X (Maybe (layout a))
+    handleMessage l  = return . pureMessage l
+
+    -- | Respond to a message by (possibly) changing our layout, but taking
+    -- no other action.  If the layout changes, the screen will be refreshed.
+    pureMessage :: layout a -> SomeMessage -> Maybe (layout a)
+    pureMessage _ _  = Nothing
+
+    -- | This should be a human-readable string that is used when selecting
+    -- layouts by name.
+    description :: layout a -> String
+    description      = show
+
+-- Here's the magic for parsing serialised state of existentially
+-- wrapped layouts: attempt to parse using the Read instance from each
+-- type in our list of types, if any suceed, take the first one.
+instance ReadableLayout a => Read (Layout a) where
+
+    -- We take the first parse only, because multiple matches indicate a bad parse.
+    readsPrec _ s = take 1 $ concatMap readLayout readTypes
+        where
+            readLayout (Layout x) = map (first Layout) $ readAsType x
+
+            -- the type indicates which Read instance to dispatch to.
+            -- That is, read asTypeOf the argument from the readTypes.
+            readAsType :: LayoutClass l a => l a -> [(l a, String)]
+            readAsType _ = reads s
+
+instance ReadableLayout a => LayoutClass Layout a where
+    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
+
+instance Show (Layout a) where show (Layout l) = show l
+
+-- | This calls doLayout if there are any windows to be laid out.
+runLayout :: LayoutClass l a => l a -> Rectangle -> StackOrNot a -> X ([(a, Rectangle)], Maybe (l a))
+runLayout l r = maybe (return ([], Nothing)) (doLayout l r)
+
+-- | Based on ideas in /An Extensible Dynamically-Typed Hierarchy of Exceptions/,
+-- Simon Marlow, 2006. Use extensible messages to the handleMessage handler.
+--
+-- User-extensible messages must be a member of this class.
+--
+class Typeable 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
-
--- | Lift an IO action into the X monad
+-- | General utilities
+--
+-- Lift an IO action into the X monad
 io :: IO a -> X a
 io = liftIO
-{-# INLINE io #-}
+
+-- | Lift an IO action into the X monad.  If the action results in an IO
+-- exception, log the exception to stderr and continue normal execution.
+catchIO :: IO () -> X ()
+catchIO f = liftIO (f `catch` \e -> hPrint stderr e >> hFlush stderr)
 
 -- | spawn. Launch an external application
 spawn :: String -> X ()
 spawn x = io $ do
     pid <- forkProcess $ do
-        forkProcess (executeFile "/bin/sh" False ["-c", x] Nothing)
+        forkProcess (createSession >> executeFile "/bin/sh" False ["-c", x] Nothing)
         exitWith ExitSuccess
-        return ()
     getProcessStatus True False pid
     return ()
 
+-- | Restart xmonad via exec().
+--
+-- If the first parameter is 'Just name', restart will attempt to execute the
+-- program corresponding to 'name'.  Otherwise, xmonad will attempt to execute
+-- the name of the current program.
+--
+-- When the second parameter is 'True', xmonad will attempt to resume with the
+-- current window state.
+restart :: Maybe String -> Bool -> X ()
+restart mprog resume = do
+    prog <- maybe (io getProgName) return mprog
+    args <- if resume then gets (("--resume":) . return . showWs . windowset) else return []
+    catchIO (executeFile prog True args Nothing)
+ where showWs = show . mapLayout show
+
 -- | Run a side effecting action with the current workspace. Like 'when' but
 whenJust :: Maybe a -> (a -> X ()) -> X ()
 whenJust mg f = maybe (return ()) f mg
 
+-- | Conditionally run an action, using a X event to decide
+whenX :: X Bool -> X () -> X ()
+whenX a f = a >>= \b -> when b f
+
 -- | A 'trace' for the X monad. Logs a string to stderr. The result may
 -- be found in your .xsession-errors file
 trace :: String -> X ()

man/xmonad.1.in

@@ -0,0 +1,49 @@
+./" man page created by David Lazar on April 24, 2007
+./" uses ``tmac.an'' macro set
+.TH xmonad 1 "18 April 07" xmonad\-1.0 "xmonad manual"
+.SH NAME
+xmonad \- a tiling window manager
+.SH DESCRIPTION
+.PP
+\fBxmonad\fR is a minimalist tiling window manager for X, written in Haskell. Windows are managed using automatic layout algorithms, which can be dynamically reconfigured. At any time windows are arranged so as to maximise the use of screen real estate. All features of the window manager are accessible purely from the keyboard: a mouse is entirely optional. \fBxmonad\fR is configured in Haskell, and custom layout algorithms may be implemented by the user in config files. A principle of \fBxmonad\fR is predictability: the user should know in advance precisely the window arrangement that will result from any action.
+.PP
+By default, \fBxmonad\fR provides three layout algorithms: tall, wide and fullscreen. In tall or wide mode, windows are tiled and arranged to prevent overlap and maximise screen use. Sets of windows are grouped together on virtual screens, and each screen retains its own layout, which may be reconfigured dynamically. Multiple physical monitors are supported via Xinerama, allowing simultaneous display of a number of screens.
+.PP
+By utilising the expressivity of a modern functional language with a rich static type system, \fBxmonad\fR provides a complete, featureful window manager in less than 500 lines of code, with an emphasis on correctness and robustness. Internal properties of the window manager are checked using a combination of static guarantees provided by the type system, and type-based automated testing. A benefit of this is that the code is simple to understand, and easy to modify.
+.SH USAGE
+.PP
+\fBxmonad\fR places each window into a "workspace". Each workspace can have any number of windows, which you can cycle though with mod-j and mod-k. Windows are either displayed full screen, tiled horizontally, or tiled vertically. You can toggle the layout mode with mod-space, which will cycle through the available modes.
+.PP
+You can switch to workspace N with mod-N. For example, to switch to workspace 5, you would press mod-5. Similarly, you can move the current window to another workspace with mod-shift-N.
+.PP
+When running with multiple monitors (Xinerama), each screen has exactly 1 workspace visible. When \fBxmonad\fR starts, workspace 1 is on screen 1, workspace 2 is on screen 2, etc. If you switch to a workspace which is currently visible on another screen, \fBxmonad\fR simply switches focus to that screen. If you switch to a workspace which is *not* visible, \fBxmonad\fR replaces the workspace on the *current* screen with the workspace you selected.
+.PP
+For example, if you have the following configuration:
+.RS
+.PP
+Screen 1: Workspace 2
+.PP
+Screen 2: Workspace 5 (current workspace)
+.RE
+.PP
+and you wanted to view workspace 7 on screen 1, you would press:
+.RS
+.PP
+mod-2 (to select workspace 2, and make screen 1 the current screen)
+.PP
+mod-7 (to select workspace 7)
+.RE
+.PP
+Since switching to the workspace currently visible on a given screen is such a common operation, shortcuts are provided: mod-{w,e,r} switch to the workspace currently visible on screens 1, 2, and 3 respectively. Likewise, shift-mod-{w,e,r} moves the current window to the workspace on that screen. Using these keys, the above example would become mod-w mod-7.
+.SS Default keyboard bindings
+___KEYBINDINGS___
+.SH EXAMPLES
+To use \fBxmonad\fR as your window manager add:
+.RS
+xmonad
+.RE
+to your \fI~/.xinitrc\fR file
+.SH CUSTOMIZATION
+\fBxmonad\fR is customized by creating a custom Config.hs and (re)compiling the source code. After recompiling, 'restart' is used to fork the new version, with changes reflected immediately.
+.SH BUGS
+Probably. If you find any, please report them: http://code.google.com/p/xmonad/issues/list

tests/Main.hs

@@ -0,0 +1,8 @@
+module Main where
+
+import qualified Properties
+
+-- This will run all of the QC files for xmonad core. Currently, that's just
+-- Properties. If any more get added, sequence the main actions together.
+main = do
+  Properties.main

tests/loc.hs

@@ -8,9 +8,7 @@ main = do foo <- getContents
           putStrLn $ show loc
           -- uncomment the following to check for mistakes in isntcomment
           -- putStr $ unlines $ actual_loc
-          when (loc > 500) $ fail "Too many lines of code!"
 
-isntcomment "" = False
 isntcomment ('-':'-':_) = False
 isntcomment ('{':'-':_) = False -- pragmas
 isntcomment _ = True

util/GenerateManpage.hs

@@ -0,0 +1,47 @@
+--
+-- Generates man/xmonad.1 from man/xmonad.1.in by filling the list of
+-- keybindings with values scraped from Config.hs
+--
+-- Format for the docstrings in Config.hs takes the following form:
+--
+-- -- mod-x %! Frob the whatsit
+-- 
+-- "Frob the whatsit" will be used as the description for keybinding "mod-x"
+--
+-- If the keybinding name is omitted, it will try to guess from the rest of the
+-- line. For example:
+--
+-- [ ((modMask .|. shiftMask, xK_Return), spawn "xterm") -- %! Launch an xterm
+--
+-- Here, mod-shift-return will be used as the keybinding name.
+--
+import Control.Monad
+import Text.Regex.Posix
+import Data.Char
+import Data.List
+
+trim :: String -> String
+trim = reverse . dropWhile isSpace . reverse . dropWhile isSpace
+
+guessKeys line = concat $ intersperse "-" (modifiers ++ [map toLower key])
+    where modifiers = map (!!1) (line =~ "(mod|shift|control)Mask")
+          (_, _, _, [key]) = line =~ "xK_(\\w+)" :: (String, String, String, [String])
+
+binding :: [String] -> (String, String)
+binding [ _, bindingLine, "", desc ] = (guessKeys bindingLine, desc)
+binding [ _, _, keyCombo, desc ] = (keyCombo, desc)
+
+allBindings :: String -> [(String, String)]
+allBindings xs = map (binding . map trim) (xs =~ "(.*)--(.*)%!(.*)")
+
+-- FIXME: What escaping should we be doing on these strings?
+troff :: (String, String) -> String
+troff (key, desc) = ".IP\n \\fB" ++ key ++ "\\fR\n" ++ desc ++ "\n"
+
+replace :: Eq a => a -> a -> [a] -> [a]
+replace x y = map (\a -> if a == x then y else a)
+
+main = do
+    troffBindings <- (concatMap troff . allBindings) `liftM` readFile "./Config.hs"
+    let sed = unlines . replace "___KEYBINDINGS___" troffBindings . lines
+    readFile "./man/xmonad.1.in" >>= return . sed >>= writeFile "./man/xmonad.1"

xmonad.cabal

@@ -1,18 +1,30 @@
 name:               xmonad
-version:            0.1
-description:        A lightweight X11 window manager.
+version:            0.4
+homepage:           http://xmonad.org
 synopsis:           A lightweight X11 window manager.
+description:
+    xmonad is a tiling window manager for X. Windows are arranged
+    automatically to tile the screen without gaps or overlap, maximising
+    screen use. All features of the window manager are accessible from
+    the keyboard: a mouse is strictly optional. xmonad is written and
+    extensible in Haskell. Custom layout algorithms, and other
+    extensions, may be written by the user in config files. Layouts are
+    applied dynamically, and different layouts may be used on each
+    workspace. Xinerama is fully supported, allowing windows to be tiled
+    on several screens.
 category:           System
 license:            BSD3
 license-file:       LICENSE
 author:             Spencer Janssen
 maintainer:         sjanssen@cse.unl.edu
-build-depends:      base>=1.0, X11>=1.1, X11-extras>=0.0, mtl>=1.0, unix>=1.0
-extra-source-files: README TODO tests/loc.hs tests/Properties.hs
+build-depends:      base>=2.0, X11>=1.2.1, X11-extras>=0.4, mtl>=1.0, unix>=1.0
+extra-source-files: README TODO tests/loc.hs tests/Properties.hs man/xmonad.1.in
+                    Config.hs-boot util/GenerateManpage.hs man/xmonad.1 man/xmonad.html
 
 executable:         xmonad
 main-is:            Main.hs
 other-modules:      Config Operations StackSet XMonad
-ghc-options:        -funbox-strict-fields -O2 -Wall -optl-Wl,-s
+ghc-options:        -funbox-strict-fields -O2 -fasm -Wall -optl-Wl,-s
 ghc-prof-options:   -prof -auto-all
 extensions:         GeneralizedNewtypeDeriving
+-- Also requires deriving Typeable, PatternGuards