README: spelling

This is important if the hook is slow (e.g. try adding "float w"
to the window-dragging hook), as it allows xmonad to keep up with
the motion of the mouse.

Config.hs

@@ -7,144 +7,180 @@
 -- Maintainer  :  dons@cse.unsw.edu.au
 -- 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
 
+-- 
+-- Useful imports
 --
--- xmonad bindings follow mostly the dwm/wmii conventions:
--- 
---     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
+--
+-- The number of workspaces (virtual screens, or window groups)
+--
+workspaces :: [WorkspaceId]
+workspaces = [0..8]
 
--- 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.
+-- |
+-- 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
+-- |
+-- 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
 
+-- |
+-- numlock handling:
+--
 -- The mask for the numlock key. 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)
+--
 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  }
+-- |
+-- Border colors for unfocused and focused windows, respectively.
+--
+normalBorderColor, focusedBorderColor :: String
+normalBorderColor  = "#dddddd"
+focusedBorderColor = "#ff0000"
 
--- The keys list.
+-- |
+-- Width of the window border in pixels
+--
+borderWidth :: Dimension
+borderWidth = 1
+
+-- |
+-- The default set of tiling algorithms
+--
+defaultLayouts :: [Layout Window]
+defaultLayouts = [ tiled , mirror tiled , full ]
+  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
+
+-- |
+-- Perform an arbitrary action on each state change.
+-- Examples include:
+--      * do nothing
+--      * log the state to stdout
+--
+logHook :: X ()
+logHook = return ()
+
+-- |
+-- The key bindings list.
+-- 
+-- The unusual comment format is used to generate the documentation
+-- automatically.
+--
 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 ), switchLayout) -- @@ Rotate through the available layout algorithms
 
-    , ((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   ), focusDown) -- @@ Move focus to the next window
+    , ((modMask,               xK_j     ), focusDown) -- @@ Move focus to the next window
+    , ((modMask,               xK_k     ), focusUp  ) -- @@ Move focus to the previous window
 
-    , ((modMask .|. shiftMask, xK_q                     ), io $ exitWith ExitSuccess)
-    , ((modMask .|. shiftMask .|. controlMask, xK_q     ), io restart)
+    -- modifying the window order
+    , ((modMask,               xK_Return), swapMaster) -- @@ Swap the focused window and the master window
+    , ((modMask .|. shiftMask, xK_j     ), swapDown  ) -- @@ Swap the focused window with the next window
+    , ((modMask .|. shiftMask, xK_k     ), 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
+
+    , ((modMask,               xK_t     ), withFocused sink) -- @@ Push window back into tiling
+
+    -- 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     ), restart Nothing True) -- @@ Restart xmonad
 
     ] ++
-    -- 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)]]
+    -- mod-[1..9] @@ Switch to workspace N
+    -- mod-shift-[1..9] @@ Move client to workspace N
+    [((m .|. modMask, k), f i)
+        | (i, k) <- zip workspaces [xK_1 ..]
+        , (f, m) <- [(view, 0), (shift, shiftMask)]]
 
-    -- Keybindings to each screen :
-    -- mod-wer (underneath 123) switches to physical/Xinerama screens 1 2 and 3
+    -- 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 >>= f)
+    [((m .|. modMask, key), screenWorkspace sc >>= flip whenJust f)
         | (key, sc) <- zip [xK_w, xK_e, xK_r] [0..]
-        , (f, m) <- [(view, 0), (tag, shiftMask)]]
+        , (f, m) <- [(windows . W.view, 0), (shift, shiftMask)]]
 
+-- |
+-- 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 >> swapMaster))
+    -- mod-button3 @@ Set the window to floating mode and resize by dragging
+    , ((modMask, button3), (\w -> focus w >> mouseResizeWindow w)) ]

Config.hs-boot

@@ -0,0 +1,8 @@
+module Config where
+import Graphics.X11.Xlib.Types (Dimension)
+import Graphics.X11.Xlib (KeyMask)
+import XMonad
+borderWidth :: Dimension
+logHook     :: X ()
+numlockMask :: KeyMask
+workspaces :: [WorkspaceId]

Main.hs

@@ -8,100 +8,142 @@
 -- 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, findIndex, workspace, tag, current, visible)
+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 winset | ("--resume" : s : _) <- args
+               , [(x, "")]            <- reads s = x
+               | otherwise = new workspaces $ zipWith SD xinesc gaps
+        gaps = take (length xinesc) $ defaultGaps ++ repeat (0,0,0,0)
+
+        safeLayouts = case defaultLayouts of [] -> (full, []); (x:xs) -> (x,xs)
+        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     = winset
+            , layouts       = M.fromList [(w, safeLayouts) | w <- workspaces]
+            , 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
+    selectInput dpy rootw $  substructureRedirectMask .|. substructureNotifyMask
+                         .|. enterWindowMask .|. leaveWindowMask .|. structureNotifyMask
     grabKeys dpy rootw
+    grabButtons dpy rootw
+
     sync dpy False
 
-    ws <- scan dpy rootw
+    ws <- scan dpy rootw -- on the resume case, will pick up new windows
     allocaXEvent $ \e ->
-        runX st $ do
-            mapM_ manage ws
-            forever $ handle =<< xevent dpy e
-      where
-        xevent d e = io (nextEvent d e >> getEvent e)
-        forever a = a >> forever a
+        runX cf st $ do
+
+            -- walk workspace, resetting X states/mask for windows
+            -- TODO, general iterators for these lists.
+            sequence_ [ setInitialProperties w >> reveal w
+                      | wk <- map W.workspace (W.current winset : W.visible winset)
+                      , w  <- W.integrate' (W.stack wk) ]
+
+            sequence_ [ setInitialProperties w >> hide w
+                      | wk <- W.hidden winset
+                      , w  <- W.integrate' (W.stack wk) ]
+
+            mapM_ manage ws -- find new windows
+            refresh
+
+            -- main loop, for all you HOF/recursion fans out there.
+            forever $ handle =<< io (nextEvent dpy e >> getEvent e)
+
+      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
-              return $ not (wa_override_redirect wa)
-                     && wa_map_state wa == waIsViewable
+  -- 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 || 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
+    ungrabKey dpy anyKey anyModifier rootw
+    forM_ (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
+         -- "If the specified KeySym is not defined for any KeyCode,
+         -- XKeysymToKeycode() returns zero."
+         when (kc /= '\0') $ mapM_ (grab kc . (mask .|.)) extraModifiers
+
+  where grab kc m = grabKey dpy kc m rootw True grabModeAsync grabModeAsync
+
+grabButtons :: Display -> Window -> IO ()
+grabButtons dpy rootw = do
+    ungrabButton dpy anyButton anyModifier rootw
+    mapM_ (\(m,b) -> mapM_ (grab b . (m .|.)) extraModifiers) (M.keys mouseBindings)
+  where grab button mask = grabButton dpy button mask rootw False buttonPressMask
+                                      grabModeAsync grabModeSync none none
 
 -- ---------------------------------------------------------------------
--- 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 +151,104 @@ 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
-        s   <- io $ keycodeToKeysym dpy code 0
-        whenJust (M.lookup (m,s) keys) id
+    | t == keyPress = withDisplay $ \dpy -> do
+        s  <- io $ keycodeToKeysym dpy code 0
+        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 (DestroyWindowEvent {ev_window = w}) = whenX (isClient w) $ unmanage w
 
--- window gone, unmanage it
-handle (UnmapEvent         {ev_window = w}) = do b <- isClient w; when b $ 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
+    io $ refreshKeyboardMapping e
     when (ev_request e == mappingKeyboard) $ withDisplay $ io . flip grabKeys w
 
--- 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 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
-
-    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
-        { 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_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
-        }
+handle e@(ConfigureRequestEvent {ev_window = w}) = withDisplay $ \dpy -> do
+    ws <- gets windowset
+    wa <- io $ getWindowAttributes dpy w
 
+    -- TODO temporary workaround for some bugs in float.  Don't call 'float' on
+    -- windows that aren't visible, because it changes the focused screen
+    let vis = any ((== findIndex w ws) . Just . tag . workspace) (current ws : visible ws)
+    if (M.member w (floating ws) && vis)
+        || 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 = fromIntegral borderWidth
+                    , wc_sibling      = ev_above 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
+-- the root may have configured
+handle (ConfigureEvent {ev_window = w}) = whenX (isRoot w) rescreen
+
+handle e = broadcastMessage e -- trace (eventName e) -- ignoring

Operations.hs

@@ -1,282 +1,581 @@
------------------------------------------------------------------------------
+{-# OPTIONS -fno-warn-orphans -fglasgow-exts #-}
+-- \^^ deriving Typeable
+-- --------------------------------------------------------------------------
 -- |
 -- 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,numlockMask)
+
 import Data.Maybe
-import Data.Bits
+import Data.List            (nub, (\\), find)
+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 ((***), first, second)
 
+import System.IO
 import Graphics.X11.Xlib
+import Graphics.X11.Xinerama (getScreenInfo)
 import Graphics.X11.Xlib.Extras
 
-import XMonad
+import qualified Data.Traversable as T
 
-import qualified StackSet as W
+-- ---------------------------------------------------------------------
+-- |
+-- 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
+    setInitialProperties w >> reveal w
 
+    -- FIXME: This is pretty awkward. We can't can't let "refresh" happen
+    -- before the call to float, because that will resize the window and
+    -- lose the default sizing.
+
+    sh <- io $ getWMNormalHints d w
+    let isFixedSize = sh_min_size sh /= Nothing && sh_min_size sh == sh_max_size sh
+    isTransient <- isJust `liftM` io (getTransientForHint d w)
+    if isFixedSize || isTransient
+        then do modify $ \s -> s { windowset = W.insertUp w (windowset s) }
+                float w -- \^^ now go the refresh.
+        else windows $ W.insertUp w
+
+-- | unmanage. A window no longer exists, remove it from the window
+-- list, on whatever workspace it is.
+--
+-- FIXME: clearFloating should be taken care of in W.delete, but if we do it
+-- there, floating status is lost when moving windows between workspaces,
+-- because W.shift calls W.delete.
+--
+-- should also unmap?
+--
+unmanage :: Window -> X ()
+unmanage w = do
+    windows (W.sink w . W.delete w)
+    setWMState w 0 {-withdrawn-}
+    modify (\s -> s {mapped = S.delete w (mapped s), waitingUnmap = M.delete w (waitingUnmap s)})
+
+-- | focus. focus window up or down. or swap various windows.
+focusUp, focusDown, swapUp, swapDown, swapMaster :: X ()
+focusUp    = windows W.focusUp
+focusDown  = windows W.focusDown
+swapUp     = windows W.swapUp
+swapDown   = windows W.swapDown
+swapMaster = windows W.swapMaster
+
+-- | shift. Move a window to a new workspace, 0 indexed.
+shift :: WorkspaceId -> X ()
+shift n = windows (W.shift n)
+
+-- | view. Change the current workspace to workspace at offset n (0 indexed).
+view :: WorkspaceId -> X ()
+view = windows . W.greedyView
+
+-- | 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
-
-    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
+data UnDoLayout = UnDoLayout deriving ( Typeable, Eq )
+instance Message UnDoLayout
 
 -- | 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
+    -- Notify visible layouts to remove decorations etc
+    -- We cannot use sendMessage because this must not call refresh ever,
+    -- and must be called on all visible workspaces.
+    broadcastMessage UnDoLayout
+    XState { windowset = old, layouts = fls } <- get
+    let oldvisible = concatMap (W.integrate' . W.stack . W.workspace) $ W.current old : W.visible old
+        ws = f old
+    modify (\s -> s { windowset = ws })
+    d <- asks display
 
--- | hide. Hide a window by moving it offscreen.
+    -- for each workspace, layout the currently visible workspaces
+    let allscreens     = W.current ws : W.visible 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
+            Just l = fmap fst $ M.lookup n fls
+            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 full viewrect tiled
+        mapM_ (uncurry tileWindow) rs
+        whenJust ml' $ \l' -> modify $ \ss ->
+                              ss { layouts = M.adjust (first (const l')) n (layouts ss) }
+
+        -- 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
+
+    setTopFocus
+    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 = withDisplay $ \d -> io $ do
+    selectInput d w $ clientMask
+    setWindowBorderWidth d w borderWidth
+
+-- | 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)
-                   grabModeAsync grabModeSync none none
+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
+    XConf { display = dpy , normalBorder = nbc, focusedBorder = fbc } <- ask
 
--- | 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
+            io $ setWindowBorder dpy otherw nbc
 
--- | 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
+    io $ setWindowBorder dpy w fbc
 
--- | 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
+-- ---------------------------------------------------------------------
+-- Managing layout
 
--- | 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
+-- | switchLayout.  Switch to another layout scheme.  Switches the
+-- layout of 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.
+--
+-- Note that the new layout's deconstructor will be called, so it should be
+-- idempotent.
+switchLayout :: X ()
+switchLayout = do
+    broadcastMessage UnDoLayout  -- calling refresh now would defeat the point of deconstruction
+    n <- gets (W.tag . W.workspace . W.current . windowset)
+    modify $ \s -> s { layouts = M.adjust switch n (layouts s) }
+    refresh
+ where switch (x, xs) = let xs' =  xs ++ [x] in (head xs', tail xs')
 
--- | 'screenWorkspace sc' returns the workspace number viewed by 'sc'.
-screenWorkspace :: ScreenId -> X WorkspaceId
-screenWorkspace sc = fmap (fromMaybe 0 . W.workspace sc) (gets workspace)
+-- | Throw a message to the current Layout possibly modifying how we
+-- layout the windows, then refresh.
+--
+sendMessage :: Message a => a -> X ()
+sendMessage a = do n <- (W.tag . W.workspace . W.current) `fmap` gets windowset
+                   Just (l,ls) <- M.lookup n `fmap` gets layouts
+                   ml' <- modifyLayout l (SomeMessage a) `catchX` return (Just l)
+                   whenJust ml' $ \l' -> do modify $ \s -> s { layouts = M.insert n (l',ls) (layouts s) }
+                                            refresh
+
+-- | 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 = do
+    ol <- gets layouts
+    nl <- T.forM ol $ \ (l,ls) -> maybe (l,ls) (flip (,) ls) `fmap`
+          (modifyLayout l (SomeMessage a) `catchX` return (Just l))
+    modify $ \s -> s { layouts = nl }
+
+instance Message Event
+
+--
+-- Builtin layout algorithms:
+--
+--   fullscreen mode
+--   tall mode
+-- 
+-- The latter algorithms support the following operations:
+--
+--      Shrink
+--      Expand
+--
+
+data Resize     = Shrink | Expand   deriving Typeable
+data IncMasterN = IncMasterN Int   deriving Typeable
+instance Message Resize
+instance Message IncMasterN
+
+-- simple fullscreen mode, just render all windows fullscreen.
+-- a plea for tuple sections: map . (,sc)
+full :: Layout a
+full = Layout { doLayout     = \sc (W.Stack f _ _) -> return ([(f, sc)],Nothing)
+              , modifyLayout = const (return Nothing) } -- no changes
+
+--
+-- The tiling mode of xmonad, and its operations.
+--
+tall :: Int -> Rational -> Rational -> Layout a
+tall nmaster delta frac =
+    Layout { doLayout     = \r -> return . (\x->(x,Nothing)) .
+                                  ap zip (tile frac r nmaster . length) . W.integrate
+           , modifyLayout = \m -> return $ 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
+
+-- | 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.
+mirror :: Layout a -> Layout a
+mirror (Layout { doLayout = dl, modifyLayout = ml }) =
+    Layout { doLayout     = \sc w -> do (wrs, ml') <- dl (mirrorRect sc) w
+                                        return (map (second mirrorRect) wrs, mirror `fmap` ml')
+           , modifyLayout = fmap (fmap mirror) . ml }
+
+-- | 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
+
+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
+
+-- | Make a floating window tiled
+sink :: Window -> X ()
+sink = windows . W.sink
+
+-- | Make a tiled window floating, using its suggested rectangle
+--
+-- TODO: float changes the set of visible workspaces when we call it for an
+-- invisible window -- this should not happen.  See 'temporary workaround' in
+-- the handler for ConfigureRequestEvent also.
+float :: Window -> X ()
+float w = withDisplay $ \d -> do
+    ws <- gets windowset
+    wa <- io $ getWindowAttributes d w
+
+    let sc = fromMaybe (W.current ws) $ find (pointWithin (fi $ wa_x wa) (fi $ wa_y wa) . screenRect . W.screenDetail) $ W.current ws : W.visible ws
+        sr = screenRect . W.screenDetail $ sc
+        sw = W.tag . W.workspace $ sc
+        bw = fi . wa_border_width $ wa
+
+    windows $ maybe id W.focusWindow (W.peek ws) . W.shift sw . W.focusWindow w . W.float w
+        (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)))
+  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)
+
+-- ---------------------------------------------------------------------
+-- 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
+
+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)
+
+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 ((fromIntegral (max 1 (ex - fromIntegral (wa_x wa)))),
+                                      (fromIntegral (max 1 (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 :: 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 +1,114 @@
-            xmonad : a lightweight X11 window manager.
+               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.)
+    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/X11-1.2.2
+    X11-extras:     http://hackage.haskell.org/cgi-bin/hackage-scripts/package/X11-extras-0.3
 
 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://darcs.haskell.org/~sjanssen/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:
+
+    0.3 release:   http://www.xmonad.org/XMonadContrib-0.3.tar.gz
+
+    darcs version: darcs get http://darcs.haskell.org/~sjanssen/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

@@ -5,248 +5,495 @@
 -- 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.
+-- 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,
+        -- *  Operations on the current stack
+        -- $stackOperations
+        peek, index, integrate, integrate', differentiate,
+        focusUp, focusDown,
+        focusWindow, tagMember, member, findIndex,
+        -- * Modifying the stackset
+        -- $modifyStackset
+        insertUp, delete, filter,
+        -- * Setting the master window
+        -- $settingMW
+        swapMaster, swapUp, swapDown, modify, modify', float, sink, -- needed by users
+        -- * Composite operations
+        -- $composite
+        shift
+    ) where
 
-    screen, peekStack, index, empty, peek, push, delete, member,
-    raiseFocus, rotate, promote, shift, view, workspace, fromList,
-    toList, size, visibleWorkspaces, swap {- helper -}
-  ) where
+import Prelude hiding (filter)
+import Data.Maybe   (listToMaybe)
+import qualified Data.List as L (delete,deleteBy,find,splitAt,filter)
+import qualified Data.Map  as M (Map,insert,delete,empty)
 
-import Data.Maybe
-import qualified Data.List     as L (delete,genericLength,elemIndex)
-import qualified Data.Map      as M
+-- $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.
 
--- | 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
+data StackSet i a sid sd =
+    StackSet { current  :: !(Screen i a sid sd)    -- ^ currently focused workspace
+             , visible  :: [Screen i a sid sd]     -- ^ non-focused workspaces, visible in xinerama
+             , hidden   :: [Workspace i a]      -- ^ workspaces not visible anywhere
+             , floating :: M.Map a RationalRect -- ^ floating windows
+             } deriving (Show, Read, Eq)
 
-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
-
-------------------------------------------------------------------------
-
--- | /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 }
-
-    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)
-
--- | /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
+-- | Visible workspaces, and their Xinerama screens.
+data Screen i a sid sd = Screen { workspace :: !(Workspace i a)
+                                , screen :: !sid
+                                , screenDetail :: !sd }
+    deriving (Show, Read, Eq)
 
+-- |
+-- A workspace is just a tag - its index - and a stack
 --
--- | /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) }
+data Workspace i a = Workspace  { tag :: !i, stack :: StackOrNot a }
+    deriving (Show, Read, Eq)
 
--- | /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.
---
-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)
+data RationalRect = RationalRect Rational Rational Rational Rational
+    deriving (Show, Read, Eq)
 
--- | /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.
+-- |
+-- 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:
 --
-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
+-- >    +-- 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)
 
--- | /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)
-                }
+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)
 
--- | /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 (?)
+-- | 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.
 --
--- | Swap first occurences of 'a' and 'b' in list.
--- If both elements are not in the list, the list is unchanged.
+-- Xinerama: Virtual workspaces are assigned to physical screens, starting at 0.
 --
--- Given a set as a list (no duplicates)
+new :: (Integral s) => [i] -> [sd] -> StackSet i a s sd
+new wids m | not (null wids) && length m <= length wids = StackSet cur visi unseen M.empty
+  where (seen,unseen) = L.splitAt (length m) $ map (flip Workspace 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.
 --
--- > 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)
+-- 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 a, Eq s, Eq i) => i -> StackSet i a s sd -> StackSet i 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 screenEq x (visible s) }
+
+    | Just x <- L.find ((i==).tag)           (hidden  s)
+    -- if it was hidden, it is raised on the xine screen currently used
+    = s { current = (current s) { workspace = x }
+        , hidden = workspace (current s) : L.delete x (hidden s) }
+
+    | otherwise = s
+ where screenEq x y = screen x == screen y
+
+    -- 'Catch'ing this might be hard. Relies on monotonically increasing
+    -- workspace tags defined in 'new'
+
+-- |
+-- 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 a, Eq s, Eq i) => i -> StackSet i a s sd -> StackSet i 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
-    insertAt n x ys = as ++ x : tail bs
-        where (as,bs) = splitAt n ys
+    wTag = (w == ) . tag
 
-swap _ _ xs = xs -- do nothing
+-- ---------------------------------------------------------------------
+-- $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 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 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 a s sd -> StackSet i 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 a s sd -> StackSet i 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 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 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 a s sd -> StackSet i 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
 
 --
--- cycling:
--- promote w = w { stacks = M.adjust next (current w) (stacks w) }
---    where next [] = []
---          next xs = last xs : init xs
+-- | /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 a s sd -> StackSet i 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 workspaces in the StackSet.
+workspaces :: StackSet i a s sd -> [Workspace i a]
+workspaces s = workspace (current s) : map workspace (visible s) ++ hidden s
+
+-- | Is the given tag present in the StackSet?
+tagMember :: Eq i => i -> StackSet i a s sd -> Bool
+tagMember t = elem t . map tag . workspaces
+
+-- |
+-- Finding if a window is in the stackset is a little tedious. We could
+-- keep a cache :: Map a i, but with more bookkeeping.
 --
 
--- | 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
+-- | /O(n)/. Is a window in the StackSet.
+member :: Eq a => a -> StackSet i 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 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 a s sd -> StackSet i 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 a s sd -> StackSet i 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 a s sd -> StackSet i 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) }
+
+------------------------------------------------------------------------
+
+-- | 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 a s sd -> StackSet i a s sd
+float w r s = s { floating = M.insert w r (floating s) }
+
+-- | Clear the floating status of a window
+sink :: Ord a => a -> StackSet i a s sd -> StackSet i a s sd
+sink w s = s { floating = M.delete w (floating s) }
+
+------------------------------------------------------------------------
+-- $settingMW
+
+-- | /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 a s sd -> StackSet i a s sd
+swapMaster = modify' $ \c -> case c of
+    Stack _ [] _  -> c    -- already master.
+    Stack t ls rs -> Stack t [] (ys ++ x : rs) where (x:ys) = reverse ls
+
+-- natural! keep focus, move current to the top, move top to current.
+-- 
+-- ---------------------------------------------------------------------
+-- $composite
+
+-- | /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 :: (Ord a, Eq s, Eq i) => i -> StackSet i a s sd -> StackSet i 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))

TODO

@@ -1,29 +1,17 @@
-- 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
+0.3 release:
+    * stable contrib repo tarball
+    * haddocks for core and contribs on xmonad.org
+    * tag xmonad
+    * tag X11-extras
+    * tag X11
+    * more QC tests
 
-        Status IO thread, the algorithm is something like this:
-            forever $ do
-                s <- getLine
-                atomic (writeTVar statusText s)
 
-        Statusbar drawing thread, waits for changes in all three TVars, and
-        redraws whenever it finds a change.
+- possibles:
+    - use more constrained type in StackSet to avoid pattern match warnings
+    - audit for events handled in dwm.
 
-- Notes on new StackSet:
+- related:
+    - xcb bindings
+    - randr
 
-   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.

XMonad.hs

@@ -9,113 +9,203 @@
 -- 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, WorkspaceId(..), ScreenId(..), ScreenDetail(..), XState(..), XConf(..), Layout(..),
+    Typeable, Message, SomeMessage(..), fromMessage, runLayout,
+    runX, catchX, io, catchIO, withDisplay, withWindowSet, isRoot, spawn, restart, trace, whenJust, whenX,
+    atom_WM_STATE, atom_WM_PROTOCOLS, atom_WM_DELETE_WINDOW
   ) where
 
-import StackSet (StackSet)
+import StackSet
 
 import Control.Monad.State
+import Control.Monad.Reader
 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
-    { display           :: Display                         -- ^ the X11 display
+    { windowset    :: !WindowSet           -- ^ workspace list
+    , mapped       :: !(S.Set Window)      -- ^ the Set of mapped windows
+    , waitingUnmap :: !(M.Map Window Int)  -- ^ the number of expected UnmapEvents
+    , layouts      :: !(M.Map WorkspaceId (Layout Window, [Layout Window]))
+                       -- ^ mapping of workspaces to descriptions of their layouts
+    , dragging     :: !(Maybe (Position -> Position -> X (), X ())) }
+data XConf = XConf
+    { display       :: Display      -- ^ the X11 display
+    , theRoot       :: !Window      -- ^ the root window
+    , normalBorder  :: !Pixel       -- ^ border color of unfocused windows
+    , focusedBorder :: !Pixel     } -- ^ border color of the focused window
 
-    , 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
-
-    , 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 Window ScreenId ScreenDetail
 
 -- | Virtual workspace indicies
-newtype WorkspaceId = W Int deriving (Eq,Ord,Show,Enum,Num,Integral,Real)
+newtype WorkspaceId = W Int deriving (Eq,Ord,Show,Read,Enum,Num,Integral,Real)
 
 -- | 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)
+
+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 ()
+runX c st (X a) = runStateT (runReaderT a c) st >> return ()
+
+-- | 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 (X job) (X errcase) = do
+    st <- get
+    c <- ask
+    (a,s') <- io ((runStateT (runReaderT job c) st) `catch`
+                  \e -> (do hPutStrLn stderr (show e); runStateT (runReaderT errcase c) st))
+    put s'
+    return a
 
 -- ---------------------------------------------------------------------
 -- 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
+-- | Layout handling
 
--- | The different layout modes
-data Layout = Full | Tall | Wide deriving (Enum, Bounded, Eq)
+-- The different layout modes
+-- 'doLayout': given a Rectangle and a Stack, layout the stack elements
+-- inside the given Rectangle.  If an element is not given a Rectangle
+-- by 'doLayout', then it is not shown on screen.  Windows are restacked
+-- according to the order they are returned by 'doLayout'.
+--
+-- 'modifyLayout' performs message handling for that layout.  If
+-- 'modifyLayout' returns Nothing, then the layout did not respond to
+-- that message and the screen is not refreshed.  Otherwise, 'modifyLayout'
+-- returns an updated 'Layout' and the screen is refreshed.
+--
+data Layout a = Layout { doLayout     :: Rectangle -> Stack a -> X ([(a, Rectangle)], Maybe (Layout a))
+                       , modifyLayout :: SomeMessage -> X (Maybe (Layout a)) }
 
--- | 'rot' for Layout.
-rotateLayout :: Layout -> Layout
-rotateLayout x = if x == maxBound then minBound else succ x
+runLayout :: Layout a -> Rectangle -> StackOrNot a -> X ([(a, Rectangle)], Maybe (Layout a))
+runLayout l r = maybe (return ([], Nothing)) (doLayout l r)
 
--- | A full description of a particular workspace's layout parameters.
-data LayoutDesc = LayoutDesc { layoutType   :: !Layout
-                             , tileFraction :: !Rational
-                             }
+-- | Based on ideas in /An Extensible Dynamically-Typed Hierarchy of Exceptions/,
+-- Simon Marlow, 2006. Use extensible messages to the modifyLayout handler.
+-- 
+-- User-extensible messages must be a member of this class.
+--
+class Typeable a => 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 -> do hPutStrLn stderr (show 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 . show . windowset) else return []
+    catchIO (executeFile prog True args Nothing)
+
 -- | 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
+
+-- 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
+
 -- | 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/Properties.hs

@@ -1,7 +1,8 @@
 {-# OPTIONS -fglasgow-exts #-}
 
-import StackSet
-import Operations (tile,vtile)
+import StackSet hiding (filter)
+import qualified StackSet as S (filter)
+import Operations (tile)
 
 import Debug.Trace
 import Data.Word
@@ -13,157 +14,494 @@ import Control.Exception    (assert)
 import Control.Monad
 import Test.QuickCheck hiding (promote)
 import System.IO
-import System.Random
+import System.Random hiding (next)
 import Text.Printf
-import Data.List            (nub,sort,group,sort,intersperse)
+import Data.List            (nub,sort,sortBy,group,sort,intersperse,genericLength)
+import qualified Data.List as L
+import Data.Char            (ord)
 import Data.Map             (keys,elems)
+import qualified Data.Map as M
 
 -- ---------------------------------------------------------------------
 -- QuickCheck properties for the StackSet
 
--- | Height of stack 'n'
-height :: Int -> T -> Int
-height i w = length (index i w)
+-- Some general hints for creating StackSet properties:
+--
+-- *  ops that mutate the StackSet are usually local
+-- *  most ops on StackSet should either be trivially reversible, or 
+--    idempotent, or both.
 
--- build (non-empty) StackSets with between 1 and 100 stacks
-instance (Integral i, Integral j, Ord a, Arbitrary a) => Arbitrary (StackSet i j a) where
+--
+-- The all important Arbitrary instance for StackSet.
+--
+instance (Integral i, Integral s, Eq a, Arbitrary a, Arbitrary sd)
+        => Arbitrary (StackSet i a s sd) where
     arbitrary = do
-        sz <- choose (1,20)
-        n  <- choose (0,sz-1)
-        sc <- choose (1,sz)
-        ls <- vector sz
-        return $ fromList (fromIntegral n,sc,ls)
+        sz <- choose (1,10)     -- number of workspaces
+        n  <- choose (0,sz-1)   -- pick one to be in focus
+        sc  <- choose (1,sz)     -- a number of physical screens
+        sds <- replicateM sc arbitrary
+        ls <- vector sz         -- a vector of sz workspaces
+
+        -- pick a random item in each stack to focus
+        fs <- sequence [ if null s then return Nothing
+                            else liftM Just (choose ((-1),length s-1))
+                       | s <- ls ]
+
+        return $ fromList (fromIntegral n, sds,fs,ls)
     coarbitrary = error "no coarbitrary for StackSet"
 
-prop_id x = fromList (toList x) == x
-    where _ = x :: T
 
-prop_member1 i n m = member i (push i x)
-    where x = empty n m :: T
+-- | 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.
+--
+-- 'o' random workspace
+-- 'm' number of physical screens
+-- 'fs' random focused window on each workspace
+-- 'xs' list of list of windows
+--
+fromList :: (Integral i, Integral s, Eq a) => (i, [sd], [Maybe Int], [[a]]) -> StackSet i a s sd
+fromList (_,_,_,[]) = error "Cannot build a StackSet from an empty list"
 
-prop_member2 i x = not (member i (delete i x))
-    where _ = x :: T
+fromList (o,m,fs,xs) =
+    let s = view o $
+                foldr (\(i,ys) s ->
+                    foldr insertUp (view i s) ys)
+                        (new [0..genericLength xs-1] m) (zip [0..] xs)
+    in foldr (\f t -> case f of
+                            Nothing -> t
+                            Just i  -> foldr (const focusUp) t [0..i] ) s fs
 
-prop_member3 i n m = member i (empty n m :: T) == False
+------------------------------------------------------------------------
 
-prop_sizepush is n m = n > 0 ==> size (foldr push x is ) == n
-    where x  = empty n m :: T
+--
+-- Just generate StackSets with Char elements.
+--
+type T = StackSet (NonNegative Int) Char Int Int
 
-prop_currentpush is n m = n > 0 ==>
-    height (current x) (foldr push x js) == length js
+-- Useful operation, the non-local workspaces
+hidden_spaces x = map workspace (visible x) ++ hidden x
+
+-- Basic data invariants of the StackSet
+--
+-- With the new zipper-based StackSet, tracking focus is no longer an
+-- issue: the data structure enforces focus by construction. 
+--
+-- But we still need to ensure there are no duplicates, and master/and
+-- the xinerama mapping aren't checked by the data structure at all.
+--
+-- * no element should ever appear more than once in a StackSet
+-- * the xinerama screen map should be:
+--          -- keys should always index valid workspaces
+--          -- monotonically ascending in the elements
+-- * the current workspace should be a member of the xinerama screens
+--
+invariant (s :: T) = and
+    -- no duplicates
+    [ noDuplicates
+
+    -- all this xinerama stuff says we don't have the right structure
+--  , validScreens
+--  , validWorkspaces
+--  , inBounds
+    ]
+
+  where
+    ws = concat [ focus t : up t ++ down t
+                  | w <- workspace (current s) : map workspace (visible s) ++ hidden s
+                  , t <- maybeToList (stack w)] :: [Char]
+    noDuplicates = nub ws == ws
+
+--  validScreens = monotonic . sort . M. . (W.current s : W.visible : W$ s
+
+--  validWorkspaces = and [ w `elem` allworkspaces | w <- (M.keys . screens) s ]
+--          where allworkspaces = map tag $ current s : prev s ++ next s
+
+--  inBounds  = and [ w >=0 && w < size s | (w,sc) <- M.assocs (screens s) ]
+
+monotonic []       = True
+monotonic (x:[])   = True
+monotonic (x:y:zs) | x == y-1  = monotonic (y:zs)
+                   | otherwise = False
+
+prop_invariant = invariant
+
+-- and check other ops preserve invariants
+prop_empty_I  (n :: Positive Int) = forAll (choose (1,fromIntegral n)) $  \m ->
+                                    forAll (vector m) $ \ms ->
+        invariant $ new [0..fromIntegral n-1] ms
+
+prop_view_I (n :: NonNegative Int) (x :: T) =
+    n `tagMember` x ==> invariant $ view (fromIntegral n) x
+
+prop_greedyView_I (n :: NonNegative Int) (x :: T) =
+    n `tagMember` x ==> invariant $ view (fromIntegral n) x
+
+prop_focusUp_I (n :: NonNegative Int) (x :: T) =
+    invariant $ foldr (const focusUp) x [1..n]
+prop_focusDown_I (n :: NonNegative Int) (x :: T) =
+    invariant $ foldr (const focusDown) x [1..n]
+
+prop_focus_I (n :: NonNegative Int) (x :: T) =
+    case peek x of
+        Nothing -> True
+        Just _  -> let w = focus . fromJust . stack . workspace . current $ foldr (const focusUp) x [1..n]
+                   in invariant $ focusWindow w x
+
+prop_insertUp_I n (x :: T) = invariant $ insertUp n x
+
+prop_delete_I (x :: T) = invariant $
+    case peek x of
+        Nothing -> x
+        Just i  -> delete i x
+
+prop_swap_master_I (x :: T) = invariant $ swapMaster x
+
+prop_swap_left_I  (n :: NonNegative Int) (x :: T) =
+    invariant $ foldr (const swapUp ) x [1..n]
+prop_swap_right_I (n :: NonNegative Int) (x :: T) =
+    invariant $ foldr (const swapDown) x [1..n]
+
+prop_shift_I (n :: NonNegative Int) (x :: T) =
+    n `tagMember` x ==> invariant $ shift (fromIntegral n) x
+
+
+-- ---------------------------------------------------------------------
+-- 'new'
+
+-- empty StackSets have no windows in them
+prop_empty (EmptyStackSet x) = 
+        all (== Nothing) [ stack w | w <- workspace (current x)
+                                        : map workspace (visible x) ++ hidden x ]
+
+-- empty StackSets always have focus on first workspace
+prop_empty_current (NonEmptyNubList ns) (NonEmptyNubList sds) =
+    -- TODO, this is ugly
+    length sds <= length ns ==>
+    tag (workspace $ current x) == head ns
+    where x = new ns sds :: T
+
+-- no windows will be a member of an empty workspace
+prop_member_empty i (EmptyStackSet x)
+    = member i x == False
+
+-- ---------------------------------------------------------------------
+-- viewing workspaces
+
+-- view sets the current workspace to 'n'
+prop_view_current (x :: T) (n :: NonNegative Int) = i `tagMember` x ==>
+    tag (workspace $ current (view i x)) == i
+  where
+    i = fromIntegral n
+
+-- view *only* sets the current workspace, and touches Xinerama. 
+-- no workspace contents will be changed.
+prop_view_local  (x :: T) (n :: NonNegative Int) = i `tagMember` x ==>
+    workspaces x == workspaces (view i x)
+  where
+    workspaces a = sortBy (\s t -> tag s `compare` tag t) $
+                                    workspace (current a)
+                                    : map workspace (visible a) ++ hidden a
+    i = fromIntegral n
+
+-- view should result in a visible xinerama screen
+-- prop_view_xinerama (x :: T) (n :: NonNegative Int) = i `tagMember` x ==>
+--     M.member i (screens (view i x))
+--   where
+--     i = fromIntegral n
+
+-- view is idempotent
+prop_view_idem (x :: T) (i :: NonNegative Int) = i `tagMember` x ==> view i (view i x) == (view i x)
+
+-- view is reversible, though shuffles the order of hidden/visible
+prop_view_reversible (i :: NonNegative Int) (x :: T) =
+    i `tagMember` x ==> normal (view n (view i x)) == normal x
+    where n  = tag (workspace $ current x)
+
+-- ---------------------------------------------------------------------
+-- greedyViewing workspaces
+
+-- greedyView sets the current workspace to 'n'
+prop_greedyView_current (x :: T) (n :: NonNegative Int) = i `tagMember` x ==>
+    tag (workspace $ current (greedyView i x)) == i
+  where
+    i = fromIntegral n
+
+-- greedyView *only* sets the current workspace, and touches Xinerama. 
+-- no workspace contents will be changed.
+prop_greedyView_local  (x :: T) (n :: NonNegative Int) = i `tagMember` x ==>
+    workspaces x == workspaces (greedyView i x)
+  where
+    workspaces a = sortBy (\s t -> tag s `compare` tag t) $
+                                    workspace (current a)
+                                    : map workspace (visible a) ++ hidden a
+    i = fromIntegral n
+
+-- greedyView is idempotent
+prop_greedyView_idem (x :: T) (i :: NonNegative Int) = i `tagMember` x ==> greedyView i (greedyView i x) == (greedyView i x)
+
+-- greedyView is reversible, though shuffles the order of hidden/visible
+prop_greedyView_reversible (i :: NonNegative Int) (x :: T) =
+    i `tagMember` x ==> normal (greedyView n (greedyView i x)) == normal x
+    where n  = tag (workspace $ current x)
+
+-- normalise workspace list
+normal s = s { hidden = sortBy g (hidden s), visible = sortBy f (visible s) }
     where
-        js = nub is
-        x = empty n m :: T
+        f = \a b -> tag (workspace a) `compare` tag (workspace b)
+        g = \a b -> tag a `compare` tag b
 
-prop_pushpeek x is = not (null is) ==> fromJust (peek (foldr push x is)) == head is
+-- ---------------------------------------------------------------------
+-- Xinerama
+
+-- every screen should yield a valid workspace
+-- prop_lookupWorkspace (n :: NonNegative Int) (x :: T) =
+--       s < M.size (screens x) ==>
+--       fromJust (lookupWorkspace s x) `elem` (map tag $ current x : prev x ++ next x)
+--     where
+--        s = fromIntegral n
+
+-- ---------------------------------------------------------------------
+-- peek/index
+
+-- peek either yields nothing on the Empty workspace, or Just a valid window
+prop_member_peek (x :: T) =
+    case peek x of
+        Nothing -> True {- then we don't know anything -}
+        Just i  -> member i x
+
+-- ---------------------------------------------------------------------
+-- index
+
+-- the list returned by index should be the same length as the actual
+-- windows kept in the zipper
+prop_index_length (x :: T) =
+    case stack . workspace . current $ x of
+        Nothing   -> length (index x) == 0
+        Just it -> length (index x) == length (focus it : up it ++ down it)
+
+-- ---------------------------------------------------------------------
+-- rotating focus
+--
+
+-- master/focus
+-- 
+-- The tiling order, and master window, of a stack is unaffected by focus changes.
+--
+prop_focus_left_master (n :: NonNegative Int) (x::T) =
+    index (foldr (const focusUp) x [1..n]) == index x
+prop_focus_right_master (n :: NonNegative Int) (x::T) =
+    index (foldr (const focusDown) x [1..n]) == index x
+prop_focusWindow_master (n :: NonNegative Int) (x :: T) =
+    case peek x of
+        Nothing -> True
+        Just _  -> let s = index x
+                       i = fromIntegral n `mod` length s
+                   in index (focusWindow (s !! i) x) == index x
+
+-- shifting focus is trivially reversible
+prop_focus_left  (x :: T) = (focusUp  (focusDown x)) == x
+prop_focus_right (x :: T) = (focusDown (focusUp  x)) ==  x
+
+-- focusWindow actually leaves the window focused...
+prop_focusWindow_works (n :: NonNegative Int) (x :: T) =
+    case peek x of
+        Nothing -> True
+        Just _  -> let s = index x
+                       i = fromIntegral n `mod` length s
+                   in (focus . fromJust . stack . workspace . current) (focusWindow (s !! i) x) == (s !! i)
+
+-- rotation through the height of a stack gets us back to the start
+prop_focus_all_l (x :: T) = (foldr (const focusUp) x [1..n]) == x
+  where n = length (index x)
+prop_focus_all_r (x :: T) = (foldr (const focusDown) x [1..n]) == x
+  where n = length (index x)
+
+-- prop_rotate_all (x :: T) = f (f x) == f x
+--     f x' = foldr (\_ y -> rotate GT y) x' [1..n]
+
+-- focus is local to the current workspace
+prop_focus_local (x :: T) = hidden_spaces (focusDown x) == hidden_spaces x
+
+prop_focusWindow_local (n :: NonNegative Int) (x::T ) =
+    case peek x of
+        Nothing -> True
+        Just _  -> let s = index x
+                       i = fromIntegral n `mod` length s
+                   in hidden_spaces (focusWindow (s !! i) x) == hidden_spaces x
+
+-- ---------------------------------------------------------------------
+-- member/findIndex
+
+--
+-- For all windows in the stackSet, findIndex should identify the
+-- correct workspace
+--
+prop_findIndex (x :: T) =
+    and [ tag w == fromJust (findIndex i x)
+        | w <- workspace (current x) : map workspace (visible x)  ++ hidden x
+        , t <- maybeToList (stack w)
+        , i <- focus t : up t ++ down t
+        ]
+
+-- ---------------------------------------------------------------------
+-- 'insert'
+
+-- inserting a item into an empty stackset means that item is now a member
+prop_insert_empty i (EmptyStackSet x)= member i (insertUp i x)
+
+-- insert should be idempotent
+prop_insert_idem i (x :: T) = insertUp i x == insertUp i (insertUp i x)
+
+-- insert when an item is a member should leave the stackset unchanged
+prop_insert_duplicate i (x :: T) = member i x ==> insertUp i x == x
+
+-- push shouldn't change anything but the current workspace
+prop_insert_local (x :: T) i = not (member i x) ==> hidden_spaces x == hidden_spaces (insertUp i x)
+
+-- Inserting a (unique) list of items into an empty stackset should
+-- result in the last inserted element having focus.
+prop_insert_peek (EmptyStackSet x) (NonEmptyNubList is) =
+    peek (foldr insertUp x is) == Just (head is)
+
+-- insert >> delete is the identity, when i `notElem` .
+-- Except for the 'master', which is reset on insert and delete.
+--
+prop_insert_delete n x = not (member n x) ==> delete n (insertUp n y) == (y :: T)
+    where
+        y = swapMaster x -- sets the master window to the current focus.
+                         -- otherwise, we don't have a rule for where master goes.
+
+-- inserting n elements increases current stack size by n
+prop_size_insert is (EmptyStackSet x) =
+        size (foldr insertUp x ws ) ==  (length ws)
+  where
+    ws   = nub is
+    size = length . index
+
+
+-- ---------------------------------------------------------------------
+-- 'delete'
+
+-- deleting the current item removes it.
+prop_delete x =
+    case peek x of
+        Nothing -> True
+        Just i  -> not (member i (delete i x))
     where _ = x :: T
 
-prop_peekmember x = case peek x of
-                            Just w  -> member w x
-                            Nothing -> True {- then we don't know anything -}
-    where _ = x :: T
+-- delete is reversible with 'insert'.
+-- It is the identiy, except for the 'master', which is reset on insert and delete.
+--
+prop_delete_insert (x :: T) =
+    case peek x of
+        Nothing -> True
+        Just n  -> insertUp n (delete n y) == y
+    where
+        y = swapMaster x
 
-prop_peek_peekStack n x =
-        if current x == n then peekStack n x == peek x
-                          else True -- so we don't exhaust
-    where _ = x :: T
+-- delete should be local
+prop_delete_local (x :: T) =
+    case peek x of
+        Nothing -> True
+        Just i  -> hidden_spaces x == hidden_spaces (delete i x)
 
-prop_notpeek_peekStack n x = current x /= n && isJust (peek x) ==> peekStack n x /= peek x
-    where _ = x :: T
+-- delete should not affect focus unless the focused element is what is being deleted
+prop_delete_focus n (x :: T) = member n x && Just n /= peek x ==> peek (delete n x) == peek x
 
-------------------------------------------------------------------------
+-- focus movement in the presence of delete:
+-- when the last window in the stack set is focused, focus moves `up'.
+-- usual case is that it moves 'down'.
+prop_delete_focus_end (x :: T) =
+    length (index x) > 1
+   ==>
+    peek (delete n y) == peek (focusUp y)
+  where
+    n = last (index x)
+    y = focusWindow n x -- focus last window in stack
 
-type T = StackSet Int Int Int
+-- focus movement in the presence of delete:
+-- when not in the last item in the stack, focus moves down
+prop_delete_focus_not_end (x :: T) =
+    length (index x) > 1 &&
+    n /= last (index x)
+   ==>
+    peek (delete n x) == peek (focusDown x)
+  where
+    Just n = peek x
 
-prop_delete_uniq i x = not (member i x) ==> delete i x == x
-    where _ = x :: T
+-- ---------------------------------------------------------------------
+-- filter
 
-prop_delete_push i x = not (member i x) ==> delete i (push i x) == x
-    where _ = x :: T
+-- preserve order
+prop_filter_order (x :: T) =
+    case stack $ workspace $ current x of
+    	Nothing -> True
+        Just s@(Stack i _ _) -> integrate' (S.filter (/= i) s) == filter (/= i) (integrate' (Just s))
 
-prop_delete2 i x =
-    delete i x == delete i (delete i x)
-    where _ = x :: T
+-- ---------------------------------------------------------------------
+-- swapUp, swapDown, swapMaster: reordiring windows
 
-prop_focus1 i x = member i x ==> peek (raiseFocus i x) == Just i
-    where _ = x :: T
+-- swap is trivially reversible
+prop_swap_left  (x :: T) = (swapUp  (swapDown x)) == x
+prop_swap_right (x :: T) = (swapDown (swapUp  x)) ==  x
+-- TODO swap is reversible
+-- swap is reversible, but involves moving focus back the window with
+-- master on it. easy to do with a mouse...
+{-
+prop_promote_reversible x b = (not . null . fromMaybe [] . flip index x . current $ x) ==>
+                            (raiseFocus y . promote . raiseFocus z . promote) x == x
+  where _            = x :: T
+        dir          = if b then LT else GT
+        (Just y)     = peek x
+        (Just (z:_)) = flip index x . current $ x
+-}
 
-prop_rotaterotate x   = rotate LT (rotate GT x) == x
-    where _ = x :: T
+-- swap doesn't change focus
+prop_swap_master_focus (x :: T) = peek x == (peek $ swapMaster x)
+--    = case peek x of
+--        Nothing -> True
+--        Just f  -> focus (stack (workspace $ current (swap x))) == f
+prop_swap_left_focus   (x :: T) = peek x == (peek $ swapUp   x)
+prop_swap_right_focus  (x :: T) = peek x == (peek $ swapDown  x)
 
-prop_viewview r  x   =
-    let n  = current x
-        sz = size x
-        i  = r `mod` sz
-    in view n (view (fromIntegral i) x) == x
+-- swap is local
+prop_swap_master_local (x :: T) = hidden_spaces x == hidden_spaces (swapMaster x)
+prop_swap_left_local   (x :: T) = hidden_spaces x == hidden_spaces (swapUp   x)
+prop_swap_right_local  (x :: T) = hidden_spaces x == hidden_spaces (swapDown  x)
 
-    where _ = x :: T
+-- rotation through the height of a stack gets us back to the start
+prop_swap_all_l (x :: T) = (foldr (const swapUp)  x [1..n]) == x
+  where n = length (index x)
+prop_swap_all_r (x :: T) = (foldr (const swapDown) x [1..n]) == x
+  where n = length (index x)
 
-prop_shiftshift r x =
-    let n  = current x
-    in shift n (shift r x) == x
-    where _ = x :: T
+prop_swap_master_idempotent (x :: T) = swapMaster (swapMaster x) == swapMaster x
 
-prop_fullcache x = cached == allvals where
-    cached  = sort . keys $ cache x
-    allvals = sort . concat . elems $ stacks x
-    _       = x :: T
+-- ---------------------------------------------------------------------
+-- shift
 
-prop_currentwsvisible x = (current x) `elem` (visibleWorkspaces x)
-    where _ = x :: T
-
-prop_ws2screen_screen2ws x = (ws == ws') && (sc == sc')
-    where ws  = sort . keys  $ ws2screen x
-          ws' = sort . elems $ screen2ws x
-          sc  = sort . keys  $ screen2ws x
-          sc' = sort . elems $ ws2screen x
-          _ = x :: T
-
-prop_screenworkspace x = all test [0..((fromIntegral $ size x)-1)]
-    where test ws = case screen ws x of
-                        Nothing -> True
-                        Just sc -> workspace sc x == Just ws
-          _ = x :: T
-
-prop_swap a b xs = swap a b (swap a b ys) == ys
-    where ys = nub xs :: [Int]
-
-------------------------------------------------------------------------
-
--- promote is idempotent
-prop_promote2 x = promote (promote x) == (promote x)
-  where _ = x :: T
-
--- focus doesn't change
-prop_promotefocus x = focus (promote x) == focus x
-  where _ = x :: T
-
--- screen certainly should't change
-prop_promotecurrent x = current (promote x) == current x
-  where _ = x :: T
-
--- the physical screen doesn't change
-prop_promotescreen n x = screen n (promote x) == screen n x
-  where _ = x :: T
-
--- promote doesn't mess with other windows
-prop_promoterotate x b = focus (rotate dir (promote x)) == focus (rotate dir x)
-  where _ = x :: T
-        dir = if b then LT else GT
+-- shift is fully reversible on current window, when focus and master
+-- are the same. otherwise, master may move.
+prop_shift_reversible i (x :: T) =
+    i `tagMember` x ==> case peek y of
+                          Nothing -> True
+                          Just _  -> normal ((view n . shift n . view i . shift i) y) == normal y
+    where
+        y = swapMaster x
+        n = tag (workspace $ current y)
 
 ------------------------------------------------------------------------
 -- some properties for layouts:
 
 -- 1 window should always be tiled fullscreen
-prop_tile_fullscreen rect = tile pct rect [1] == [(1, rect)]
-
-prop_vtile_fullscreen rect = vtile pct rect [1] == [(1, rect)]
+{-
+prop_tile_fullscreen rect = tile pct rect 1 1 == [rect]
 
 -- multiple windows 
-prop_tile_non_overlap rect windows = noOverlaps (tile pct rect windows)
-  where _ = rect :: Rectangle
-
-prop_vtile_non_overlap rect windows = noOverlaps (vtile pct rect windows)
+prop_tile_non_overlap rect windows nmaster = noOverlaps (tile pct rect nmaster windows)
   where _ = rect :: Rectangle
 
 pct = 3 % 100
@@ -171,8 +509,8 @@ pct = 3 % 100
 noOverlaps []  = True
 noOverlaps [_] = True
 noOverlaps xs  = and [ verts a `notOverlap` verts b
-                     | (_,a) <- xs
-                     , (_,b) <- filter (\(_,b) -> a /= b) xs
+                     | a <- xs
+                     , b <- filter (a /=) xs
                      ]
     where
       verts (Rectangle a b w h) = (a,b,a + fromIntegral w - 1, b + fromIntegral h - 1)
@@ -182,9 +520,174 @@ noOverlaps xs  = and [ verts a `notOverlap` verts b
         =  (top1 < bottom2 || top2 < bottom1)
         || (right1 < left2 || right2 < left1)
 
+-}
 
 ------------------------------------------------------------------------
 
+main :: IO ()
+main = do
+    args <- getArgs
+    let n = if null args then 100 else read (head args)
+    (results, passed) <- liftM unzip $ mapM (\(s,a) -> printf "%-25s: " s >> a n) tests
+    printf "Passed %d tests!\n" (sum passed)
+    when (not . and $ results) $ fail "Not all tests passed!"
+ where
+
+    tests =
+        [("StackSet invariants" , mytest prop_invariant)
+
+        ,("empty: invariant"    , mytest prop_empty_I)
+        ,("empty is empty"      , mytest prop_empty)
+        ,("empty / current"     , mytest prop_empty_current)
+        ,("empty / member"      , mytest prop_member_empty)
+
+        ,("view : invariant"    , mytest prop_view_I)
+        ,("view sets current"   , mytest prop_view_current)
+        ,("view idempotent"     , mytest prop_view_idem)
+        ,("view reversible"    , mytest prop_view_reversible)
+--      ,("view / xinerama"     , mytest prop_view_xinerama)
+        ,("view is local"       , mytest prop_view_local)
+
+        ,("greedyView : invariant"    , mytest prop_greedyView_I)
+        ,("greedyView sets current"   , mytest prop_greedyView_current)
+        ,("greedyView idempotent"     , mytest prop_greedyView_idem)
+        ,("greedyView reversible"     , mytest prop_greedyView_reversible)
+        ,("greedyView is local"       , mytest prop_greedyView_local)
+--
+--      ,("valid workspace xinerama", mytest prop_lookupWorkspace)
+
+        ,("peek/member "        , mytest prop_member_peek)
+
+        ,("index/length"        , mytest prop_index_length)
+
+        ,("focus left : invariant", mytest prop_focusUp_I)
+        ,("focus right: invariant", mytest prop_focusDown_I)
+        ,("focusWindow: invariant", mytest prop_focus_I)
+        ,("focus left/master"   , mytest prop_focus_left_master)
+        ,("focus right/master"  , mytest prop_focus_right_master)
+        ,("focusWindow master"  , mytest prop_focusWindow_master)
+        ,("focus left/right"    , mytest prop_focus_left)
+        ,("focus right/left"    , mytest prop_focus_right)
+        ,("focus all left  "    , mytest prop_focus_all_l)
+        ,("focus all right "    , mytest prop_focus_all_r)
+        ,("focus is local"      , mytest prop_focus_local)
+        ,("focusWindow is local", mytest prop_focusWindow_local)
+        ,("focusWindow works"   , mytest prop_focusWindow_works)
+
+        ,("findIndex"           , mytest prop_findIndex)
+
+        ,("insert: invariant"   , mytest prop_insertUp_I)
+        ,("insert/new"          , mytest prop_insert_empty)
+        ,("insert is idempotent", mytest prop_insert_idem)
+        ,("insert is reversible", mytest prop_insert_delete)
+        ,("insert is local"     , mytest prop_insert_local)
+        ,("insert duplicates"   , mytest prop_insert_duplicate)
+        ,("insert/peek "        , mytest prop_insert_peek)
+        ,("insert/size"         , mytest prop_size_insert)
+
+        ,("delete: invariant"   , mytest prop_delete_I)
+        ,("delete/empty"        , mytest prop_empty)
+        ,("delete/member"       , mytest prop_delete)
+        ,("delete is reversible", mytest prop_delete_insert)
+        ,("delete is local"     , mytest prop_delete_local)
+        ,("delete/focus"        , mytest prop_delete_focus)
+        ,("delete  last/focus up", mytest prop_delete_focus_end)
+        ,("delete ~last/focus down", mytest prop_delete_focus_not_end)
+
+        ,("filter preserves order", mytest prop_filter_order)
+
+        ,("swapMaster: invariant", mytest prop_swap_master_I)
+        ,("swapUp: invariant" , mytest prop_swap_left_I)
+        ,("swapDown: invariant", mytest prop_swap_right_I)
+        ,("swapMaster id on focus", mytest prop_swap_master_focus)
+        ,("swapUp id on focus", mytest prop_swap_left_focus)
+        ,("swapDown id on focus", mytest prop_swap_right_focus)
+        ,("swapMaster is idempotent", mytest prop_swap_master_idempotent)
+        ,("swap all left  "     , mytest prop_swap_all_l)
+        ,("swap all right "     , mytest prop_swap_all_r)
+        ,("swapMaster is local" , mytest prop_swap_master_local)
+        ,("swapUp is local"   , mytest prop_swap_left_local)
+        ,("swapDown is local"  , mytest prop_swap_right_local)
+
+        ,("shift: invariant"    , mytest prop_shift_I)
+        ,("shift is reversible" , mytest prop_shift_reversible)
+
+{-
+        ,("tile 1 window fullsize", mytest prop_tile_fullscreen)
+        ,("tiles never overlap",    mytest prop_tile_non_overlap)
+-}
+
+        ]
+
+------------------------------------------------------------------------
+--
+-- QC driver
+--
+
+debug = False
+
+mytest :: Testable a => a -> Int -> IO (Bool, Int)
+mytest a n = mycheck defaultConfig
+    { configMaxTest=n
+    , configEvery   = \n args -> let s = show n in s ++ [ '\b' | _ <- s ] } a
+ -- , configEvery= \n args -> if debug then show n ++ ":\n" ++ unlines args else [] } a
+
+mycheck :: Testable a => Config -> a -> IO (Bool, Int)
+mycheck config a = do
+    rnd <- newStdGen
+    mytests config (evaluate a) rnd 0 0 []
+
+mytests :: Config -> Gen Result -> StdGen -> Int -> Int -> [[String]] -> IO (Bool, Int)
+mytests config gen rnd0 ntest nfail stamps
+    | ntest == configMaxTest config = done "OK," ntest stamps >> return (True, ntest)
+    | nfail == configMaxFail config = done "Arguments exhausted after" ntest stamps >> return (True, ntest)
+    | otherwise               =
+      do putStr (configEvery config ntest (arguments result)) >> hFlush stdout
+         case ok result of
+           Nothing    ->
+             mytests config gen rnd1 ntest (nfail+1) stamps
+           Just True  ->
+             mytests config gen rnd1 (ntest+1) nfail (stamp result:stamps)
+           Just False ->
+             putStr ( "Falsifiable after "
+                   ++ show ntest
+                   ++ " tests:\n"
+                   ++ unlines (arguments result)
+                    ) >> hFlush stdout >> return (False, ntest)
+     where
+      result      = generate (configSize config ntest) rnd2 gen
+      (rnd1,rnd2) = split rnd0
+
+done :: String -> Int -> [[String]] -> IO ()
+done mesg ntest stamps = putStr ( mesg ++ " " ++ show ntest ++ " tests" ++ table )
+  where
+    table = display
+            . map entry
+            . reverse
+            . sort
+            . map pairLength
+            . group
+            . sort
+            . filter (not . null)
+            $ stamps
+
+    display []  = ".\n"
+    display [x] = " (" ++ x ++ ").\n"
+    display xs  = ".\n" ++ unlines (map (++ ".") xs)
+
+    pairLength xss@(xs:_) = (length xss, xs)
+    entry (n, xs)         = percentage n ntest
+                       ++ " "
+                       ++ concat (intersperse ", " xs)
+
+    percentage n m        = show ((100 * n) `div` m) ++ "%"
+
+------------------------------------------------------------------------
+
+instance Arbitrary Char where
+    arbitrary = choose ('a','z')
+    coarbitrary n = coarbitrary (ord n)
+
 instance Random Word8 where
   randomR = integralRandomR
   random = randomR (minBound,maxBound)
@@ -223,6 +726,7 @@ instance Arbitrary Rectangle where
         sw <- arbitrary
         sh <- arbitrary
         return $ Rectangle sx sy sw sh
+    coarbitrary = undefined
 
 instance Arbitrary Rational where
     arbitrary = do
@@ -233,115 +737,65 @@ instance Arbitrary Rational where
     coarbitrary = undefined
 
 ------------------------------------------------------------------------
+-- QC 2
 
-main :: IO ()
-main = do
-    args <- getArgs
-    let n = if null args then 100 else read (head args)
-    mapM_ (\(s,a) -> printf "%-25s: " s >> a n) tests
+-- from QC2
+-- | NonEmpty xs: guarantees that xs is non-empty.
+newtype NonEmptyList a = NonEmpty [a]
+ deriving ( Eq, Ord, Show, Read )
+
+instance Arbitrary a => Arbitrary (NonEmptyList a) where
+  arbitrary   = NonEmpty `fmap` (arbitrary `suchThat` (not . null))
+  coarbitrary = undefined
+
+newtype NonEmptyNubList a = NonEmptyNubList [a]
+ deriving ( Eq, Ord, Show, Read )
+
+instance (Eq a, Arbitrary a) => Arbitrary (NonEmptyNubList a) where
+  arbitrary   = NonEmptyNubList `fmap` ((liftM nub arbitrary) `suchThat` (not . null))
+  coarbitrary = undefined
+
+type Positive a = NonZero (NonNegative a)
+
+newtype NonZero a = NonZero a
+ deriving ( Eq, Ord, Num, Integral, Real, Enum, Show, Read )
+
+instance (Num a, Ord a, Arbitrary a) => Arbitrary (NonZero a) where
+  arbitrary = fmap NonZero $ arbitrary `suchThat` (/= 0)
+  coarbitrary = undefined
+
+newtype NonNegative a = NonNegative a
+ deriving ( Eq, Ord, Num, Integral, Real, Enum, Show, Read )
+
+instance (Num a, Ord a, Arbitrary a) => Arbitrary (NonNegative a) where
+  arbitrary =
+    frequency
+      [ (5, (NonNegative . abs) `fmap` arbitrary)
+      , (1, return 0)
+      ]
+  coarbitrary = undefined
+
+newtype EmptyStackSet = EmptyStackSet T deriving Show
+
+instance Arbitrary EmptyStackSet where
+    arbitrary = do
+        (NonEmptyNubList ns)  <- arbitrary
+        (NonEmptyNubList sds) <- arbitrary
+        -- there cannot be more screens than workspaces:
+        return . EmptyStackSet . new ns $ take (min (length ns) (length sds)) sds
+
+-- | Generates a value that satisfies a predicate.
+suchThat :: Gen a -> (a -> Bool) -> Gen a
+gen `suchThat` p =
+  do mx <- gen `suchThatMaybe` p
+     case mx of
+       Just x  -> return x
+       Nothing -> sized (\n -> resize (n+1) (gen `suchThat` p))
+
+-- | Tries to generate a value that satisfies a predicate.
+suchThatMaybe :: Gen a -> (a -> Bool) -> Gen (Maybe a)
+gen `suchThatMaybe` p = sized (try 0 . max 1)
  where
-    n = 100
-
-    tests =
-        [("read.show        ", mytest prop_id)
-
-        ,("member/push      ", mytest prop_member1)
-        ,("member/peek      ", mytest prop_peekmember)
-        ,("member/delete    ", mytest prop_member2)
-        ,("member/empty     ", mytest prop_member3)
-
-        ,("size/push        ", mytest prop_sizepush)
-        ,("height/push      ", mytest prop_currentpush)
-        ,("push/peek        ", mytest prop_pushpeek)
-
-        ,("peek/peekStack"  ,  mytest prop_peek_peekStack)
-        ,("not . peek/peekStack", mytest prop_notpeek_peekStack)
-
-        ,("delete/not.member", mytest prop_delete_uniq)
-        ,("delete idempotent", mytest prop_delete2)
-        ,("delete.push identity" , mytest prop_delete_push)
-
-        ,("focus",             mytest prop_focus1)
-
-        ,("rotate/rotate    ", mytest prop_rotaterotate)
-
-        ,("view/view        ", mytest prop_viewview)
-        ,("fullcache        ", mytest prop_fullcache)
-        ,("currentwsvisible ", mytest prop_currentwsvisible)
-        ,("ws screen mapping", mytest prop_ws2screen_screen2ws)
-        ,("screen/workspace ", mytest prop_screenworkspace)
-
-        ,("promote idempotent", mytest prop_promote2)
-        ,("promote focus",      mytest prop_promotefocus)
-        ,("promote current",    mytest prop_promotecurrent)
-        ,("promote only swaps", mytest prop_promoterotate)
-        ,("promote/screen" ,    mytest prop_promotescreen)
-
-        ,("swap",               mytest prop_swap)
-
-------------------------------------------------------------------------
-
-        ,("tile 1 window fullsize", mytest prop_tile_fullscreen)
-        ,("vtile 1 window fullsize", mytest prop_vtile_fullscreen)
-        ,("vtiles never overlap",    mytest prop_vtile_non_overlap     )
-
-        ]
-
-debug = False
-
-mytest :: Testable a => a -> Int -> IO ()
-mytest a n = mycheck defaultConfig
-    { configMaxTest=n
-    , configEvery= \n args -> if debug then show n ++ ":\n" ++ unlines args else [] } a
-
-mycheck :: Testable a => Config -> a -> IO ()
-mycheck config a = do
-    rnd <- newStdGen
-    mytests config (evaluate a) rnd 0 0 []
-
-mytests :: Config -> Gen Result -> StdGen -> Int -> Int -> [[String]] -> IO ()
-mytests config gen rnd0 ntest nfail stamps
-    | ntest == configMaxTest config = do done "OK," ntest stamps
-    | nfail == configMaxFail config = do done "Arguments exhausted after" ntest stamps
-    | otherwise               =
-      do putStr (configEvery config ntest (arguments result)) >> hFlush stdout
-         case ok result of
-           Nothing    ->
-             mytests config gen rnd1 ntest (nfail+1) stamps
-           Just True  ->
-             mytests config gen rnd1 (ntest+1) nfail (stamp result:stamps)
-           Just False ->
-             putStr ( "Falsifiable after "
-                   ++ show ntest
-                   ++ " tests:\n"
-                   ++ unlines (arguments result)
-                    ) >> hFlush stdout
-     where
-      result      = generate (configSize config ntest) rnd2 gen
-      (rnd1,rnd2) = split rnd0
-
-done :: String -> Int -> [[String]] -> IO ()
-done mesg ntest stamps = putStr ( mesg ++ " " ++ show ntest ++ " tests" ++ table )
-  where
-    table = display
-            . map entry
-            . reverse
-            . sort
-            . map pairLength
-            . group
-            . sort
-            . filter (not . null)
-            $ stamps
-
-    display []  = ".\n"
-    display [x] = " (" ++ x ++ ").\n"
-    display xs  = ".\n" ++ unlines (map (++ ".") xs)
-
-    pairLength xss@(xs:_) = (length xss, xs)
-    entry (n, xs)         = percentage n ntest
-                       ++ " "
-                       ++ concat (intersperse ", " xs)
-
-    percentage n m        = show ((100 * n) `div` m) ++ "%"
-
-------------------------------------------------------------------------
+  try _ 0 = return Nothing
+  try k n = do x <- resize (2*k+n) gen
+               if p x then return (Just x) else try (k+1) (n-1)

tests/loc.hs

@@ -8,7 +8,6 @@ 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

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 +1,31 @@
 name:               xmonad
-version:            0.1
-description:        A lightweight X11 window manager.
+version:            0.3
+homepage:           http://xmonad.org
 synopsis:           A lightweight X11 window manager.
+description:
+    Xmonad 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.  Xmonad is configured in
+    Haskell, and custom layout algorithms may be implemented by the user
+    in config files. A principle of Xmonad is predictability: the user
+    should know in advance precisely the window arrangement that will
+    result from any action.
 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>=0.3, 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