From 8b3fae31bfdefbb7449c295ea4b8a569b7033380 Mon Sep 17 00:00:00 2001
From: Don Stewart <dons@cse.unsw.edu.au>
Date: Wed, 7 Mar 2007 07:45:39 +0100
Subject: focus left and right (mod-j/mod-k)

darcs-hash:20070307064539-9c5c1-2578ea84009c449b3baeba8a58bfda5b39096fba
---
 Main.hs | 65 +++++++++++++++++++++++++++--------------------------------------
 W.hs    | 31 ++++++++++++++++++++++++++++---
 2 files changed, 55 insertions(+), 41 deletions(-)

diff --git a/Main.hs b/Main.hs
index 7cf9858..3974467 100644
--- a/Main.hs
+++ b/Main.hs
@@ -67,7 +67,9 @@ keys =
     [ (mod1Mask .|. shiftMask, xK_Return, spawn "xterm")
     , (mod1Mask,               xK_p,      spawn "exe=`dmenu_path | dmenu` && exec $exe")
     , (controlMask,            xK_space,  spawn "gmrun")
-    , (mod1Mask,               xK_Tab,    switch)
+    , (mod1Mask,               xK_Tab,    focus 1)
+    , (mod1Mask,               xK_j,      focus 1)
+    , (mod1Mask,               xK_k,      focus (-1))
     , (mod1Mask .|. shiftMask, xK_q,      io $ exitWith ExitSuccess)
     ]
 
@@ -112,63 +114,50 @@ handle _ = return ()
 -- ---------------------------------------------------------------------
 -- Managing windows
 
--- | Modify the current window list with a pure funtion, and refresh
-withWindows :: (Windows -> Windows) -> W ()
-withWindows f = do
-    modifyWindows f
-    refresh
-
--- |  Run an action on the currently focused window
-withCurrent :: (Window -> W ()) -> W ()
-withCurrent f = do
-    ws <- gets windows
-    case ws of
-        []    -> return ()
-        (w:_) -> f w
-
 --
 -- | refresh. Refresh the currently focused window. Resizes to full
 -- screen and raises the window.
 --
 refresh :: W ()
-refresh = withCurrent $ \w -> do
-    d  <- gets display
-    sw <- gets screenWidth
-    sh <- gets screenHeight
-    io $ do moveResizeWindow d w 0 0 (fromIntegral sw) (fromIntegral sh)
-            raiseWindow d w
+refresh = do
+    ws <- gets windows
+    case ws of
+        []    -> return ()
+        (w:_) -> do
+            d  <- gets display
+            sw <- liftM fromIntegral (gets screenWidth)
+            sh <- liftM fromIntegral (gets screenHeight)
+            io $ do moveResizeWindow d w 0 0 sw sh
+                    raiseWindow d w
+
+-- | Modify the current window list with a pure funtion, and refresh
+withWindows :: (Windows -> Windows) -> W ()
+withWindows f = do
+    modifyWindows f
+    refresh
 
---
 -- | manage. Add a new window to be managed
---
 manage :: Window -> W ()
 manage w = do
     trace "manage"
     d  <- gets display
-    withWindows $ \ws -> if w `elem` ws then ws else w:ws -- a set
+    withWindows (nub . (w :))
     io $ mapWindow d w
 
---
 -- | unmanage, a window no longer exists, remove it from the stack
---
 unmanage :: Window -> W ()
 unmanage w = do
     dpy <- gets display
-    io $ grabServer dpy
-    modifyWindows (filter (/= w))
-    io $ sync dpy False
-    io $ ungrabServer dpy
-    refresh
+    io $ do grabServer dpy
+            sync dpy False
+            ungrabServer dpy
+    withWindows $ filter (/= w)
 
---
--- | switch. switch focus to next window in list.
+-- | focus. focus to window at offset 'n' in list.
 -- The currently focused window is always the head of the list
---
-switch :: W ()
-switch = withWindows rotate
+focus :: Int -> W ()
+focus n = withWindows (rotate n)
 
---
 -- | spawn. Launch an external application
---
 spawn :: String -> W ()
 spawn = io_ . runCommand
diff --git a/W.hs b/W.hs
index 88af0d3..cf1c1fb 100644
--- a/W.hs
+++ b/W.hs
@@ -29,6 +29,14 @@ data WState = WState
     , windows       :: !Windows
     }
 
+--
+-- Multithreaded issues:
+--
+--   We'll want a status bar, it will probably read from stdin
+--   but will thus need to run in its own thread, and modify its status
+--   bar window
+--
+
 type Windows = [Window]
 
 -- | The W monad, a StateT transformer over IO encapuslating the window
@@ -74,6 +82,23 @@ forever a = a >> forever a
 snoc :: [a] -> a -> [a]
 snoc xs x = xs ++ [x]
 
--- | Rotate a list one element
-rotate []     = []
-rotate (x:xs) = xs `snoc` x
+-- | Rotate a list by 'n' elements.
+--
+-- for xs = [5..8] ++ [1..4]
+--
+--  rotate 0 
+--  [5,6,7,8,1,2,3,4]
+--
+--  rotate 1
+--  [6,7,8,1,2,3,4,5]
+--
+--  rotate (-1)
+--  [4,5,6,7,8,1,2,3]
+--
+rotate n xs = take l . drop offset . cycle $ xs
+  where
+    l      = length xs
+    offset | n < 0     = l + n
+           | otherwise = n
+
+
-- 
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