Add experimental xmonadPropLog function

XMonad/Hooks/DynamicLog.hs

@@ -29,6 +29,8 @@ module XMonad.Hooks.DynamicLog (
     dynamicLog,
     dynamicLogXinerama,
 
+    xmonadPropLog,
+
     -- * Build your own formatter
     dynamicLogWithPP,
     dynamicLogString,
@@ -63,6 +65,10 @@ import qualified Data.Map as M
 import Data.Ord ( comparing )
 import qualified XMonad.StackSet as S
 import System.IO
+
+import qualified Codec.Binary.UTF8.String as UTF8
+import Foreign.C (CChar)
+
 import XMonad.Util.WorkspaceCompare
 import XMonad.Util.NamedWindows
 import XMonad.Util.Run
@@ -198,6 +204,19 @@ statusBar cmd pp k conf = do
  where
     keys' = (`M.singleton` sendMessage ToggleStruts) . k
 
+-- | Write a string to the property _XMONAD_LOG on the root window.  This
+-- property is of type UTF8_STRING.
+xmonadPropLog :: String -> X ()
+xmonadPropLog msg = do
+    d <- asks display
+    r <- asks theRoot
+    xlog <- getAtom "_XMONAD_LOG"
+    ustring <- getAtom "UTF8_STRING"
+    io $ changeProperty8 d r xlog ustring propModeReplace (encodeCChar msg)
+ where
+    encodeCChar :: String -> [CChar]
+    encodeCChar = map fromIntegral . UTF8.encode
+
 -- |
 -- Helper function which provides ToggleStruts keybinding
 --