xmonad-contrib/XMonad/Util/SpawnOnce.hs

60 lines
2.0 KiB
Haskell

-----------------------------------------------------------------------------
-- |
-- Module : XMonad.Util.SpawnOnce
-- Description : A module for spawning a command once, and only once.
-- Copyright : (c) Spencer Janssen 2009
-- License : BSD3-style (see LICENSE)
--
-- Maintainer : spencerjanssen@gmail.com
-- Stability : unstable
-- Portability : not portable
--
-- A module for spawning a command once, and only once. Useful to start
-- status bars and make session settings inside startupHook.
--
-----------------------------------------------------------------------------
module XMonad.Util.SpawnOnce (spawnOnce, spawnOnOnce, spawnNOnOnce, spawnAndDoOnce) where
import XMonad
import XMonad.Actions.SpawnOn
import Data.Set as Set
import qualified XMonad.Util.ExtensibleState as XS
import XMonad.Prelude
newtype SpawnOnce = SpawnOnce { unspawnOnce :: Set String }
deriving (Read, Show)
instance ExtensionClass SpawnOnce where
initialValue = SpawnOnce Set.empty
extensionType = PersistentExtension
doOnce :: (String -> X ()) -> String -> X ()
doOnce f s = do
b <- XS.gets (Set.member s . unspawnOnce)
unless b $ do
f s
XS.modify (SpawnOnce . Set.insert s . unspawnOnce)
-- | The first time 'spawnOnce' is executed on a particular command,
-- that command is executed. Subsequent invocations for a command do
-- nothing.
spawnOnce :: String -> X ()
spawnOnce = doOnce spawn
-- | Like spawnOnce but launches the application on the given workspace.
spawnOnOnce :: WorkspaceId -> String -> X ()
spawnOnOnce ws = doOnce (spawnOn ws)
-- | Lanch the given application n times on the specified
-- workspace. Subsequent attempts to spawn this application will be
-- ignored.
spawnNOnOnce :: Int -> WorkspaceId -> String -> X ()
spawnNOnOnce n ws = doOnce (replicateM_ n . spawnOn ws)
-- | Spawn the application once and apply the manage hook. Subsequent
-- attempts to spawn this application will be ignored.
spawnAndDoOnce :: ManageHook -> String -> X ()
spawnAndDoOnce mh = doOnce (spawnAndDo mh)