[Xmonad] Show name of focused window in status bar

[Kai Grossjohann]

Do people think that showing the name of the currently focused window in
the status bar (in addition to the workspaces) would be a worthwhile
addition?

If so, could you advise how to improve the quality of the code I've
concocted?  Given that I don't know Haskell, I'm happy that it runs.

Here's what I did.

To NamedWindows.hs I added the following function (and exported it):

unWindow :: NamedWindow -> String
unWindow (NW n _) = n

In Config.hs I wrote:

dynamicLogWName :: X ()
dynamicLogWName = do
    withWindowSet $ io . putStr . pprWindowSet
    io (putStr " // ")
    withNamedWindow $ io . putStr . unWindow
    io (putStrLn "")

logHook = dynamicLogWName

tia,
Kai