[xmonad] ManageHook and doF

[Владимир Байраковский]

Hi!

I have manageHook like this:

myManageHook = composeAll [
        className   =? "Firefox"            --> doF(W.shift "web"),
        className   =? "Gajim.py"           --> doF(W.shift "chat"),
        className   =? "Deadbeef"           --> doF(W.shift "music"),
        title       =? "Gajim"              --> doFloat,
        className   =? "MPlayer"            --> doCenterFloat,
        ]

so, if some workspace does not exist by some reason, the new window
will appear on current workspace. How to chek if workspace exists and
create it before "W.shift" action?
I think addWorkspace from XMonad.Actions.DynamicWorkspaces can do
this, but I don't know haskell well to write some function that can be
used with doF.