    -----------------------------------------------------------------------------
    -- |
    -- Module      :  XMonad.Hooks.DynamicHooks
    -- Description :  One-shot and permanent ManageHooks that can be updated at runtime.
    -- Copyright   :  (c) Braden Shepherdson 2008
    -- License     :  BSD-style (as xmonad)
    --
    -- Maintainer  :  Braden.Shepherdson@gmail.com
    -- Stability   :  unstable
    -- Portability :  unportable
    --
    -- One-shot and permanent ManageHooks that can be updated at runtime.
    --
    -----------------------------------------------------------------------------

    module XMonad.Hooks.DynamicHooks (
      -- * Usage
      -- $usage
      dynamicMasterHook
      ,addDynamicHook
      ,updateDynamicHook
      ,oneShotHook
      ) where

    import XMonad
    import XMonad.Prelude
    import qualified XMonad.Util.ExtensibleState as XS

    -- $usage
    -- Provides two new kinds of 'ManageHooks' that can be defined at runtime.
    --
    -- * One-shot 'ManageHooks' that are deleted after they execute.
    --
    -- * Permanent 'ManageHooks' (unless you want to destroy them)
    --
    -- Note that you will lose all dynamically defined 'ManageHook's when you @mod+q@!
    -- If you want them to last, you should create them as normal in your @xmonad.hs@.
    --
    -- To use this module, add 'dynamicMasterHook' to your 'manageHook':
    --
    -- > xmonad { manageHook = myManageHook <> dynamicMasterHook }
    --
    -- You can then use the supplied functions in your keybindings:
    --
    -- > ((modMask,xK_a), oneShotHook (className =? "example") doFloat)
    --

    data DynamicHooks = DynamicHooks
        { DynamicHooks -> [(Query Bool, ManageHook)]
    transients :: [(Query Bool, ManageHook)]
        , DynamicHooks -> ManageHook
    permanent  :: ManageHook }

    instance ExtensionClass DynamicHooks where
        initialValue :: DynamicHooks
    initialValue = [(Query Bool, ManageHook)] -> ManageHook -> DynamicHooks
    DynamicHooks [] ManageHook
    forall m. Monoid m => m
    idHook

    -- this hook is always executed, and the contents of the stored hooks checked.
    -- note that transient hooks are run second, therefore taking precedence
    -- over permanent ones on matters such as which workspace to shift to.
    -- doFloat and doIgnore are idempotent.
    -- | Master 'ManageHook' that must be in your @xmonad.hs@ 'ManageHook'.
    dynamicMasterHook :: ManageHook
    dynamicMasterHook :: ManageHook
    dynamicMasterHook = Query Window
    forall r (m :: * -> *). MonadReader r m => m r
    ask Query Window -> (Window -> ManageHook) -> ManageHook
    forall a b. Query a -> (a -> Query b) -> Query b
    forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
    >>= \Window
    w -> X (Endo WindowSet) -> ManageHook
    forall a. X a -> Query a
    liftX (X (Endo WindowSet) -> ManageHook)
    -> X (Endo WindowSet) -> ManageHook
    forall a b. (a -> b) -> a -> b
    $ do
      dh <- X DynamicHooks
    forall a (m :: * -> *). (ExtensionClass a, XLike m) => m a
    XS.get
      (Endo f)  <- runQuery (permanent dh) w
      ts <- mapM (\(Query Bool
    q,ManageHook
    a) -> Query Bool -> Window -> X Bool
    forall a. Query a -> Window -> X a
    runQuery Query Bool
    q Window
    w X Bool
    -> (Bool -> X (Bool, (Query Bool, ManageHook)))
    -> X (Bool, (Query Bool, ManageHook))
    forall a b. X a -> (a -> X b) -> X b
    forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
    >>= \Bool
    x -> (Bool, (Query Bool, ManageHook))
    -> X (Bool, (Query Bool, ManageHook))
    forall a. a -> X a
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Bool
    x,(Query Bool
    q, ManageHook
    a))) (transients dh)
      let (ts',nts) = partition fst ts
      gs <- mapM (flip runQuery w . snd . snd) ts'
      let (Endo g) = fromMaybe (Endo id) $ listToMaybe gs
      XS.put $ dh { transients = map snd nts }
      return $ Endo $ f . g

    -- | Appends the given 'ManageHook' to the permanent dynamic 'ManageHook'.
    addDynamicHook :: ManageHook -> X ()
    addDynamicHook :: ManageHook -> X ()
    addDynamicHook ManageHook
    m = (ManageHook -> ManageHook) -> X ()
    updateDynamicHook (ManageHook -> ManageHook -> ManageHook
    forall a. Semigroup a => a -> a -> a
    <> ManageHook
    m)

    -- | Modifies the permanent 'ManageHook' with an arbitrary function.
    updateDynamicHook :: (ManageHook -> ManageHook) -> X ()
    updateDynamicHook :: (ManageHook -> ManageHook) -> X ()
    updateDynamicHook ManageHook -> ManageHook
    f = (DynamicHooks -> DynamicHooks) -> X ()
    forall a (m :: * -> *).
    (ExtensionClass a, XLike m) =>
    (a -> a) -> m ()
    XS.modify ((DynamicHooks -> DynamicHooks) -> X ())
    -> (DynamicHooks -> DynamicHooks) -> X ()
    forall a b. (a -> b) -> a -> b
    $ \DynamicHooks
    dh -> DynamicHooks
    dh { permanent = f (permanent dh) }

    -- | Creates a one-shot 'ManageHook'. Note that you have to specify the two
    -- parts of the 'ManageHook' separately. Where you would usually write:
    --
    -- > className =? "example" --> doFloat
    --
    -- you must call 'oneShotHook' as
    --
    -- > oneShotHook dynHooksRef (className =? "example) doFloat
    --
    oneShotHook :: Query Bool -> ManageHook -> X ()
    oneShotHook :: Query Bool -> ManageHook -> X ()
    oneShotHook Query Bool
    q ManageHook
    a = (DynamicHooks -> DynamicHooks) -> X ()
    forall a (m :: * -> *).
    (ExtensionClass a, XLike m) =>
    (a -> a) -> m ()
    XS.modify ((DynamicHooks -> DynamicHooks) -> X ())
    -> (DynamicHooks -> DynamicHooks) -> X ()
    forall a b. (a -> b) -> a -> b
    $ \DynamicHooks
    dh -> DynamicHooks
    dh { transients = (q,a):transients dh }