X.H.DynamicLog: Add dzenStrip to remove formatting, for use in dzenPP's ppUrgent.

This function was written by Wirt Wolff. This change should allow UrgencyHook
to work out of the box with dzen and dzenPP, rather than the colours being
overridden so even though UrgencyHook is working, it doesn't change colours.

XMonad/Hooks/DynamicLog.hs

@@ -39,7 +39,7 @@ module XMonad.Hooks.DynamicLog (
 
     -- * Formatting utilities
     wrap, pad, shorten,
-    xmobarColor, dzenColor, dzenEscape,
+    xmobarColor, dzenColor, dzenEscape, dzenStrip,
 
     -- * Internal formatting functions
     pprWindowSet,
@@ -332,6 +332,17 @@ dzenColor fg bg = wrap (fg1++bg1) (fg2++bg2)
 dzenEscape :: String -> String
 dzenEscape = concatMap (\x -> if x == '^' then "^^" else [x])
 
+-- | Strip dzen formatting (used in ppUrgent)
+dzenStrip :: String -> String
+dzenStrip = strip [] where
+    strip keep [] = keep
+    strip keep ('^':'^':x) = strip (keep ++ "^") x
+    strip keep ('^':x) = strip keep (drop 1 . dropWhile (')' /=) $ x)
+    strip keep x = let (good,x') = span ('^' /=) x
+        in strip (keep ++ good) x'
+
+
+
 -- | Use xmobar escape codes to output a string with given foreground
 --   and background colors.
 xmobarColor :: String  -- ^ foreground color: a color name, or #rrggbb format
@@ -421,7 +432,7 @@ dzenPP = defaultPP { ppCurrent  = dzenColor "white" "#2b4f98" . pad
                      , ppVisible  = dzenColor "black" "#999999" . pad
                      , ppHidden   = dzenColor "black" "#cccccc" . pad
                      , ppHiddenNoWindows = const ""
-                     , ppUrgent   = dzenColor "red" "yellow"
+                     , ppUrgent   = dzenColor "red" "yellow" . dzenStrip
                      , ppWsSep    = ""
                      , ppSep      = ""
                      , ppLayout   = dzenColor "black" "#cccccc" .