Move screen details into StackSet

darcs-hash:20070629213917-a5988-3ad31d8f028efcec41c9c4805c01c2d42c0009b2

5 files changed, 99 insertions, 90 deletions

diff --git a/Main.hs b/Main.hs
index 156cea7..64929c5 100644
--- a/Main.hs
+++ b/Main.hs
@@ -52,7 +52,8 @@ main = do
 
     let winset | ("--resume" : s : _) <- args
                , [(x, "")]            <- reads s = x
-               | otherwise = new [0..fromIntegral workspaces-1] (fromIntegral $ length xinesc)
+               | otherwise = new [0..fromIntegral workspaces-1] $ 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
@@ -63,8 +64,6 @@ main = do
         st = XState
             { windowset     = winset
             , layouts       = M.fromList [(w, safeLayouts) | w <- [0 .. W workspaces - 1]]
-            , statusGaps    = take (length xinesc) $ defaultGaps ++ repeat (0,0,0,0)
-            , xineScreens   = xinesc
             , mapped        = S.empty
             , waitingUnmap  = M.empty }
 
diff --git a/Operations.hs b/Operations.hs
index 2bb348a..ee5a5bc 100644
--- a/Operations.hs
+++ b/Operations.hs
@@ -21,7 +21,7 @@ import qualified StackSet as W
 import {-# SOURCE #-} Config (borderWidth,logHook,numlockMask)
 
 import Data.Maybe
-import Data.List            (genericIndex, nub, (\\), findIndex)
+import Data.List            (nub, (\\), find)
 import Data.Bits            ((.|.), (.&.), complement)
 import Data.Ratio
 import qualified Data.Map as M
@@ -98,11 +98,10 @@ view = windows . W.view
 -- Taking a function giving the current screen, and current geometry.
 modifyGap :: (Int -> (Int,Int,Int,Int) -> (Int,Int,Int,Int)) -> X ()
 modifyGap f = do
-    XState { windowset = ws, statusGaps = gaps } <- get
-    let n       = fromIntegral . W.screen $ W.current ws
-        (a,i:b) = splitAt n gaps
-    modify $ \s -> s { statusGaps = a ++ f n i : b }
-    refresh
+    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.
@@ -135,7 +134,7 @@ windows f = do
     -- 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, xineScreens = xinesc, statusGaps = gaps } <- get
+    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 })
@@ -149,8 +148,8 @@ windows f = do
             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))
-            (Rectangle sx sy sw sh) = genericIndex xinesc (W.screen w)
-            (gt,gb,gl,gr)           = genericIndex gaps   (W.screen w)
+            (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))
 
@@ -257,13 +256,13 @@ rescreen :: X ()
 rescreen = do
     xinesc <- withDisplay (io . getScreenInfo)
 
-    modify (\s -> s { xineScreens = xinesc
-                    , statusGaps  = take (length xinesc) $ (statusGaps s) ++ repeat (0,0,0,0) })
-
     windows $ \ws@(W.StackSet { W.current = v, W.visible = vs, W.hidden = hs }) ->
-        let (x:xs, ys) = splitAt (length xinesc) $ map W.workspace (v:vs) ++ hs
-        in  ws { W.current = W.Screen x 0
-               , W.visible = zipWith W.Screen xs [1 ..]
+        let (xs, ys) = splitAt (length xinesc) $ map W.workspace (v:vs) ++ hs
+            (a:as)   = zipWith3 W.Screen xs [1..] $ 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 }
 
 -- ---------------------------------------------------------------------
@@ -476,20 +475,19 @@ sink = windows . W.sink
 -- | Make a tiled window floating, using its suggested rectangle
 float :: Window -> X ()
 float w = withDisplay $ \d -> do
-    XState { xineScreens = xinesc, windowset = ws } <- get
+    ws <- gets windowset
     wa <- io $ getWindowAttributes d w
 
-    let sid = fromMaybe (W.screen . W.current $ ws) (fmap fi $ findIndex (pointWithin (fi (wa_x wa)) (fi (wa_y wa))) xinesc)
-        sc = genericIndex xinesc sid
+    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
 
-    wid <- screenWorkspace sid
-
-    windows $ W.shift wid . W.focusWindow w . W.float w
-        (W.RationalRect ((fi (wa_x wa) - fi (rect_x sc)) % fi (rect_width sc))
-                        ((fi (wa_y wa) - fi (rect_y sc)) % fi (rect_height sc))
-                        (fi (wa_width  wa + bw*2) % fi (rect_width sc))
-                        (fi (wa_height wa + bw*2) % fi (rect_height sc)))
+    windows $ 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) &&
diff --git a/StackSet.hs b/StackSet.hs
index 3d369f9..037b124 100644
--- a/StackSet.hs
+++ b/StackSet.hs
@@ -37,7 +37,7 @@ module StackSet (
 
 import Prelude hiding (filter)
 import Data.Maybe   (listToMaybe)
-import qualified Data.List as L (delete,find,genericSplitAt,filter)
+import qualified Data.List as L (delete,deleteBy,find,splitAt,filter)
 import qualified Data.Map  as M (Map,insert,delete,empty)
 
 -- $intro
@@ -146,15 +146,17 @@ import qualified Data.Map  as M (Map,insert,delete,empty)
 -- that are produced are used to track those workspaces visible as
 -- Xinerama screens, and those workspaces not visible anywhere.
 
-data StackSet i a sid =
-    StackSet { current  :: !(Screen i a sid)    -- ^ currently focused workspace
-             , visible  :: [Screen i a sid]     -- ^ non-focused workspaces, visible in xinerama
+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)
 
 -- | Visible workspaces, and their Xinerama screens.
-data Screen i a sid = Screen { workspace :: !(Workspace i a), screen :: !sid }
+data Screen i a sid sd = Screen { workspace :: !(Workspace i a)
+                                , screen :: !sid
+                                , screenDetail :: !sd }
     deriving (Show, Read, Eq)
 
 -- |
@@ -205,10 +207,10 @@ abort x = error $ "xmonad: StackSet: " ++ x
 --
 -- Xinerama: Virtual workspaces are assigned to physical screens, starting at 0.
 --
-new :: Integral s => [i] -> s -> StackSet i a s
-new (wid:wids) m | m > 0 = StackSet cur visi unseen M.empty
-  where (seen,unseen) = L.genericSplitAt m $ Workspace wid Nothing : [ Workspace i Nothing | i <- wids]
-        (cur:visi)    = [ Screen i s |  (i,s) <- zip seen [0..] ]
+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"
 
@@ -222,21 +224,22 @@ new _ _ = abort "non-positive argument to StackSet.new"
 -- 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 -> StackSet i a s
+view :: (Eq a, Eq s, Eq i) => i -> StackSet i a s sd -> StackSet i a s sd
 view i s
     | not (elem i $ map tag $ workspaces 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.delete x (visible s) }
+    = 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 = Screen x (screen (current s))
+    = 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'
@@ -246,8 +249,8 @@ view i s
 
 -- | 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 -> Maybe i
-lookupWorkspace sc w = listToMaybe [ tag i | Screen i s <- current w : visible w, s == sc ]
+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
@@ -258,13 +261,13 @@ lookupWorkspace sc w = listToMaybe [ tag i | Screen i s <- current w : visible w
 -- 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 -> b
+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 -> StackSet i a s
+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 }}}
 
@@ -272,14 +275,14 @@ modify d f s = s { current = (current 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 -> StackSet i a s
+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 -> Maybe a
+peek :: StackSet i a s sd -> Maybe a
 peek = with Nothing (return . focus)
 
 -- |
@@ -321,7 +324,7 @@ filter p (Stack f ls rs) = case L.filter p (f:rs) of
 -- the head of the list. The implementation is given by the natural
 -- integration of a one-hole list cursor, back to a list.
 --
-index :: Eq a => StackSet i a s -> [a]
+index :: Eq a => StackSet i a s sd -> [a]
 index = with [] integrate
 
 --  let is = t : r ++ reverse l in take (length is) (dropWhile (/= m) (cycle is))
@@ -338,7 +341,7 @@ index = with [] integrate
 -- if we reach the end. Again the wrapping model should 'cycle' on
 -- the current stack.
 -- 
-focusUp, focusDown, swapUp, swapDown :: StackSet i a s -> StackSet i a s
+focusUp, focusDown, swapUp, swapDown :: StackSet i a s sd -> StackSet i a s sd
 focusUp   = modify' focusUp'
 focusDown = modify' (reverseStack . focusUp' . reverseStack)
 
@@ -360,7 +363,7 @@ reverseStack (Stack t ls rs) = Stack t rs ls
 -- | /O(1) on current window, O(n) in general/. Focus the window 'w', 
 -- and set its workspace as current.
 --
-focusWindow :: (Integral i, Eq s, Eq a) => a -> StackSet i a s -> StackSet i a s
+focusWindow :: (Integral i, Eq s, Eq a) => 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
@@ -369,11 +372,11 @@ focusWindow w s | Just w == peek s = s
 
 
 -- | Get a list of all workspaces in the StackSet.
-workspaces :: StackSet i a s -> [Workspace i a]
+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 -> Bool
+tagMember :: Eq i => i -> StackSet i a s sd -> Bool
 tagMember t = elem t . map tag . workspaces
 
 -- |
@@ -382,13 +385,13 @@ tagMember t = elem t . map tag . workspaces
 --
 
 -- | /O(n)/. Is a window in the StackSet.
-member :: Eq a => a -> StackSet i a s -> Bool
+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 -> Maybe i
+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
@@ -411,11 +414,11 @@ findIndex a s = listToMaybe
 -- 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 -> StackSet i a s
+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 -> StackSet i a 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 }
@@ -434,7 +437,7 @@ insertUp a s = if member a s then s else insert
 --   * deleting the master window resets it to the newly focused window
 --   * otherwise, delete doesn't affect the master.
 --
-delete :: (Integral i, Ord a, Eq s) => a -> StackSet i a s -> StackSet i a s
+delete :: (Integral i, Ord a, Eq s) => a -> StackSet i a s sd -> StackSet i a s sd
 delete w s | Just w == peek s = remove s -- common case. 
            | otherwise = maybe s (removeWindow.tag.workspace.current $ s) (findIndex w s)
   where
@@ -454,11 +457,11 @@ delete w s | Just w == peek s = remove s -- common case.
 
 -- | 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 -> StackSet i a s
+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 -> StackSet i a s
+sink :: Ord a => a -> StackSet i a s sd -> StackSet i a s sd
 sink w s = s { floating = M.delete w (floating s) }
 
 ------------------------------------------------------------------------
@@ -467,7 +470,7 @@ sink w s = s { floating = M.delete w (floating s) }
 -- | /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 -> StackSet i a s
+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
@@ -483,7 +486,7 @@ swapMaster = modify' $ \c -> case c of
 -- 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, Integral i) => i -> StackSet i a s -> StackSet i a s
+shift :: (Ord a, Eq s, Integral i) => i -> StackSet i a s sd -> StackSet i a s sd
 shift n s = if and [n >= 0,n `tagMember` s, n /= tag (workspace (current s))]
             then maybe s go (peek s) else s
     where go w = foldr ($) s [view (tag (workspace (current s))),insertUp w,view n,delete w]
diff --git a/XMonad.hs b/XMonad.hs
index bc54bfd..8eec7b1 100644
--- a/XMonad.hs
+++ b/XMonad.hs
@@ -15,7 +15,7 @@
 -----------------------------------------------------------------------------
 
 module XMonad (
-    X, WindowSet, WorkspaceId(..), ScreenId(..), XState(..), XConf(..), Layout(..),
+    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
@@ -30,6 +30,8 @@ import System.Posix.Process (executeFile, forkProcess, getProcessStatus, createS
 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
@@ -39,8 +41,6 @@ import qualified Data.Set as S
 -- Just the display, width, height and a window list
 data XState = XState
     { windowset    :: !WindowSet           -- ^ workspace list
-    , xineScreens  :: ![Rectangle]         -- ^ dimensions of each screen
-    , statusGaps   :: ![(Int,Int,Int,Int)] -- ^ width of status bar on each screen
     , 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])) }
@@ -51,7 +51,7 @@ data XConf = XConf
     , normalBorder  :: !Pixel       -- ^ border color of unfocused windows
     , focusedBorder :: !Pixel     } -- ^ border color of the focused window
 
-type WindowSet = StackSet WorkspaceId Window ScreenId
+type WindowSet = StackSet WorkspaceId Window ScreenId ScreenDetail
 
 -- | Virtual workspace indicies
 newtype WorkspaceId = W Int deriving (Eq,Ord,Show,Read,Enum,Num,Integral,Real)
@@ -59,6 +59,10 @@ newtype WorkspaceId = W Int deriving (Eq,Ord,Show,Read,Enum,Num,Integral,Real)
 -- | Physical screen indicies
 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
diff --git a/tests/Properties.hs b/tests/Properties.hs
index c96dcc0..452267f 100644
--- a/tests/Properties.hs
+++ b/tests/Properties.hs
@@ -33,11 +33,13 @@ import qualified Data.Map as M
 --
 -- The all important Arbitrary instance for StackSet.
 --
-instance (Integral i, Integral s, Eq a, Arbitrary a) => Arbitrary (StackSet i a s) where
+instance (Integral i, Integral s, Eq a, Arbitrary a, Arbitrary sd)
+        => Arbitrary (StackSet i a s sd) where
     arbitrary = do
         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
+        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
@@ -45,7 +47,7 @@ instance (Integral i, Integral s, Eq a, Arbitrary a) => Arbitrary (StackSet i a
                             else liftM Just (choose ((-1),length s-1))
                        | s <- ls ]
 
-        return $ fromList (fromIntegral n, fromIntegral sc,fs,ls)
+        return $ fromList (fromIntegral n, sds,fs,ls)
     coarbitrary = error "no coarbitrary for StackSet"
 
 
@@ -59,14 +61,9 @@ instance (Integral i, Integral s, Eq a, Arbitrary a) => Arbitrary (StackSet i a
 -- 'fs' random focused window on each workspace
 -- 'xs' list of list of windows
 --
-fromList :: (Integral i, Integral s, Eq a) => (i, s, [Maybe Int], [[a]]) -> StackSet i a s
+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"
 
-fromList (n,m,fs,xs) | n < 0 || n >= genericLength xs
-                = error $ "Cursor index is out of range: " ++ show (n, length xs)
-                  | m < 1 || m >  genericLength xs
-                = error $ "Can't have more screens than workspaces: " ++ show (m, length xs)
-
 fromList (o,m,fs,xs) =
     let s = view o $
                 foldr (\(i,ys) s ->
@@ -81,7 +78,7 @@ fromList (o,m,fs,xs) =
 --
 -- Just generate StackSets with Char elements.
 --
-type T = StackSet (NonNegative Int) Char Int
+type T = StackSet (NonNegative Int) Char Int Int
 
 -- Useful operation, the non-local workspaces
 hidden_spaces x = map workspace (visible x) ++ hidden x
@@ -131,8 +128,9 @@ monotonic (x:y:zs) | x == y-1  = monotonic (y:zs)
 prop_invariant = invariant
 
 -- and check other ops preserve invariants
-prop_empty_I  (n :: Positive Int) = forAll (choose (1,fromIntegral n)) $ \m ->
-        invariant $ new [0..fromIntegral n-1] m
+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
@@ -170,19 +168,20 @@ prop_shift_I (n :: NonNegative Int) (x :: T) =
 -- 'new'
 
 -- empty StackSets have no windows in them
-prop_empty (NonEmptyNubList ns) (m :: Positive Int) =
-       all (== Nothing) [ stack w | w <- workspace (current x)
+prop_empty (EmptyStackSet x) = 
+        all (== Nothing) [ stack w | w <- workspace (current x)
                                         : map workspace (visible x) ++ hidden x ]
 
-    where x = new ns (fromIntegral m) :: T
-
 -- empty StackSets always have focus on first workspace
-prop_empty_current (NonEmptyNubList ns) (m :: Positive Int) = tag (workspace $ current x) == head ns
-    where x = new ns (fromIntegral m) :: T
+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 (NonEmptyNubList ns) (m :: Positive Int)
-    = member i (new ns (fromIntegral m) :: T) == False
+prop_member_empty i (EmptyStackSet x)
+    = member i x == False
 
 -- ---------------------------------------------------------------------
 -- viewing workspaces
@@ -320,8 +319,7 @@ prop_findIndex (x :: T) =
 -- 'insert'
 
 -- inserting a item into an empty stackset means that item is now a member
-prop_insert_empty i (NonEmptyNubList ns) (m :: Positive Int) = member i (insertUp i x)
-    where x = new ns (fromIntegral m) :: T
+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)
@@ -334,9 +332,8 @@ prop_insert_local (x :: T) i = not (member i x) ==> hidden_spaces x == hidden_sp
 
 -- Inserting a (unique) list of items into an empty stackset should
 -- result in the last inserted element having focus.
-prop_insert_peek (NonEmptyNubList ns) (m :: Positive Int) (NonEmptyNubList is) =
+prop_insert_peek (EmptyStackSet x) (NonEmptyNubList is) =
     peek (foldr insertUp x is) == Just (head is)
-    where x = new ns (fromIntegral m) :: T
 
 -- insert >> delete is the identity, when i `notElem` .
 -- Except for the 'master', which is reset on insert and delete.
@@ -347,11 +344,10 @@ prop_insert_delete n x = not (member n x) ==> delete n (insertUp n y) == (y :: T
                          -- otherwise, we don't have a rule for where master goes.
 
 -- inserting n elements increases current stack size by n
-prop_size_insert is (NonEmptyNubList ns) (m :: Positive Int) =
+prop_size_insert is (EmptyStackSet x) =
         size (foldr insertUp x ws ) ==  (length ws)
   where
     ws   = nub is
-    x    = new ns (fromIntegral m) :: T
     size = length . index
 
 
@@ -731,6 +727,15 @@ instance (Num a, Ord a, Arbitrary a) => Arbitrary (NonNegative a) where
       ]
   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 =