LayoutModifier: add emptyLayoutMod for dealing with empty workspaces

darcs-hash:20080124015605-32816-cdcd0b9509d793e85a2a0acd8d61e1ee69455568.gz

1 files changed, 10 insertions, 0 deletions

diff --git a/XMonad/Layout/LayoutModifier.hs b/XMonad/Layout/LayoutModifier.hs
index 96772e4..933b4e7 100644
--- a/XMonad/Layout/LayoutModifier.hs
+++ b/XMonad/Layout/LayoutModifier.hs
@@ -49,6 +49,9 @@ class (Show (m a), Read (m a)) => LayoutModifier m a where
     pureModifier :: m a -> Rectangle -> Stack a -> [(a, Rectangle)]
                  -> ([(a, Rectangle)], Maybe (m a))
     pureModifier _ _ _ wrs = (wrs, Nothing)
+    emptyLayoutMod :: m a -> Rectangle -> [(a, Rectangle)]
+                   -> X ([(a, Rectangle)], Maybe (m a))
+    emptyLayoutMod _ _ _ = return ([], Nothing)
     hook :: m a -> X ()
     hook _ = return ()
     unhook :: m a -> X ()
@@ -64,6 +67,13 @@ instance (LayoutModifier m a, LayoutClass l a) => LayoutClass (ModifiedLayout m
                       Just m' -> Just $ (ModifiedLayout m') $ maybe l id ml'
                       Nothing -> ModifiedLayout m `fmap` ml'
            return (ws', ml'')
+    emptyLayout (ModifiedLayout m l) r =
+        do (ws, ml') <- emptyLayout l r
+           (ws',mm') <- emptyLayoutMod m r ws
+           let ml'' = case mm' of
+                      Just m' -> Just $ (ModifiedLayout m') $ maybe l id ml'
+                      Nothing -> ModifiedLayout m `fmap` ml'
+           return (ws', ml'')
     handleMessage (ModifiedLayout m l) mess =
         do mm' <- handleMessOrMaybeModifyIt m mess
            ml' <- case mm' of