Experimental ability to pin a window using Mod+p

A pinned window will always try to stay on the same screen in the sname
position if it can.

1 files changed, 9 insertions, 2 deletions

diff --git a/src/Rahm/Desktop/Hooks/WindowChange.hs b/src/Rahm/Desktop/Hooks/WindowChange.hs
index 32c854b..0902f53 100644
--- a/src/Rahm/Desktop/Hooks/WindowChange.hs
+++ b/src/Rahm/Desktop/Hooks/WindowChange.hs
@@ -26,11 +26,18 @@ import qualified XMonad.Util.ExtensibleState as XS (get, put)
 type WindowStack = StackSet WorkspaceId () Window ScreenId ScreenDetail
 
 -- Type of hook. Takes the last WindowStack and the new WindowStack
-type StackChangeHook = WindowStack -> WindowStack -> X ()
+newtype StackChangeHook = StackChangeHook (WindowStack -> WindowStack -> X ())
 
 newtype LastState = LastState (Maybe WindowStack)
   deriving (Read, Show)
 
+instance Semigroup StackChangeHook where
+  StackChangeHook f1 <> StackChangeHook f2 =
+    StackChangeHook $ \l c -> f1 l c >> f2 l c
+
+instance Monoid StackChangeHook where
+  mempty = StackChangeHook $ \_ _ -> return ()
+
 instance Default LastState where
   def = LastState def
 
@@ -45,7 +52,7 @@ instance ExtensionClass LastState where
 --
 -- If the first window is Nothing, this is the first time XMonad started.
 withStackChangeHook :: StackChangeHook -> XConfig l -> XConfig l
-withStackChangeHook fn config =
+withStackChangeHook (StackChangeHook fn) config =
   config
     { logHook = do
         logHook config