Factor workspace sorting into a separate module

XMonad/Util/WorkspaceCompare.hs

@@ -0,0 +1,37 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  XMonad.Util.WorkspaceCompare
+-- Copyright   :  (c) Spencer Janssen <sjanssen@cse.unl.edu>
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer  :  Spencer Janssen <sjanssen@cse.unl.edu>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+
+module XMonad.Util.WorkspaceCompare ( getWsIndex, getWsCompare, getSortByTag ) where
+
+import XMonad
+import qualified XMonad.StackSet as S
+import Data.List
+import Data.Monoid
+
+getWsIndex :: X (WorkspaceId -> Maybe Int)
+getWsIndex = do
+    spaces <- asks (workspaces . config)
+    return $ flip elemIndex spaces
+
+getWsCompare :: X (WorkspaceId -> WorkspaceId -> Ordering)
+getWsCompare = do
+    wsIndex <- getWsIndex
+    return $ \a b -> f (wsIndex a) (wsIndex b) `mappend` compare a b
+ where
+   f Nothing Nothing   = EQ
+   f (Just _) Nothing  = LT
+   f Nothing (Just _)  = GT
+   f (Just x) (Just y) = compare x y
+
+getSortByTag :: X ([WindowSpace] -> [WindowSpace])
+getSortByTag = do
+    cmp <- getWsCompare
+    return $ sortBy (\a b -> cmp (S.tag a) (S.tag b))