Add a modify' function on extensible state

XMonad/Hooks/WorkspaceHistory.hs

@@ -77,8 +77,10 @@ workspaceHistoryHook = gets windowset >>= (XS.modify . updateLastActiveOnEachScr
 -- | Like 'workspaceHistoryHook', but with the ability to exclude
 -- certain workspaces.
 workspaceHistoryHookExclude :: [WorkspaceId] -> X ()
-workspaceHistoryHookExclude ws =
-  gets windowset >>= XS.modify . updateLastActiveOnEachScreenExclude ws
+workspaceHistoryHookExclude ws = do
+  s <- gets windowset
+  let update' a = force (updateLastActiveOnEachScreenExclude ws s a)
+  XS.modify' update'
 
 workspaceHistoryWithScreen :: X [(ScreenId, WorkspaceId)]
 workspaceHistoryWithScreen = XS.gets history

XMonad/Util/ExtensibleState.hs

@@ -20,6 +20,7 @@ module XMonad.Util.ExtensibleState (
                               -- $usage
                               put
                               , modify
+                              , modify'
                               , remove
                               , get
                               , gets
@@ -90,6 +91,11 @@ modifyStateExts f = State.modify $ \st -> st { extensibleState = f (extensibleSt
 modify :: (ExtensionClass a, XLike m) => (a -> a) -> m ()
 modify f = put . f =<< get
 
+-- | Like @modify@ but the result value is applied strictly in respect to
+-- the monadic environment.
+modify' :: (ExtensionClass a, XLike m) => (a -> a) -> m ()
+modify' f = (\a -> let res = f a in res `seq` put res) =<< get
+
 -- | Add a value to the extensible state field. A previously stored value with the same
 -- type will be overwritten. (More precisely: A value whose string representation of its type
 -- is equal to the new one's)