add RotView module.

RotView.hs

@@ -0,0 +1,30 @@
+module XMonad.RotView ( rotView ) where
+
+-- To use:
+-- include XMonad.RotView
+
+--    , ((modMask .|. shiftMask, xK_Right), rotView True)
+--    , ((modMask .|. shiftMask, xK_Left), rotView False)
+
+import qualified Data.Map as M
+import Control.Monad.State
+
+import Operations ( view )
+import XMonad ( X, WorkspaceId, workspace )
+import StackSet ( StackSet, focus )
+import qualified StackSet as W ( current )
+
+rotView :: Bool -> X m ()
+rotView b = do ws <- gets workspace
+               let m = W.current ws
+                   allws = if b then allWorkspaces ws else reverse $ allWorkspaces ws
+                   n1 = safehead allws m
+                   rot (f:fs) | f == m = safehead fs n1
+                              | otherwise = rot fs
+                   rot [] = n1
+                   safehead fs f = case fs of { [] -> f; f':_ -> f'; }
+               view (rot allws)
+
+-- | A list of all the workspaces.
+allWorkspaces :: StackSet WorkspaceId j a -> [WorkspaceId]
+allWorkspaces = M.keys . focus