93 lines
3.2 KiB
Haskell

{-# LANGUAGE FlexibleInstances, FlexibleContexts, MultiParamTypeClasses #-}
{-# LANGUAGE PatternSynonyms #-}
--------------------------------------------------------------------------------
-- |
-- Module : XMonad.Layout.StateFull
-- Description : The StateFull Layout & FocusTracking Layout Transformer
-- Copyright : (c) 2018 L. S. Leary
-- License : BSD3-style (see LICENSE)
--
-- Maintainer : L. S. Leary
-- Stability : unstable
-- Portability : unportable
--
-- Provides StateFull: a stateful form of Full that does not misbehave when
-- floats are focused, and the FocusTracking layout transformer by means of
-- which StateFull is implemented. FocusTracking simply holds onto the last
-- true focus it was given and continues to use it as the focus for the
-- transformed layout until it sees another. It can be used to improve the
-- behaviour of a child layout that has not been given the focused window.
--------------------------------------------------------------------------------
module XMonad.Layout.StateFull (
-- * Usage
-- $Usage
pattern StateFull,
StateFull,
FocusTracking(..),
focusTracking
) where
import XMonad hiding ((<&&>))
import XMonad.Prelude (fromMaybe, (<|>))
import qualified XMonad.StackSet as W
import XMonad.Util.Stack (findZ)
-- $Usage
--
-- To use it, first you need to:
--
-- > import XMonad.Layout.StateFull
--
-- Then to toggle your tiled layout with @StateFull@, you can do:
--
-- > main = xmonad def { layoutHook = someTiledLayout ||| StateFull }
--
-- Or, some child layout that depends on focus information can be made to fall
-- back on the last focus it had:
--
-- > main = xmonad def
-- > { layoutHook = someParentLayoutWith aChild (focusTracking anotherChild) }
-- | The @FocusTracking@ data type for which the @LayoutClass@ instance is
-- provided.
data FocusTracking l a = FocusTracking (Maybe a) (l a)
deriving (Show, Read)
-- | Transform a layout into one that remembers and uses its last focus.
focusTracking :: l a -> FocusTracking l a
focusTracking = FocusTracking Nothing
-- | A type synonym to match the @StateFull@ pattern synonym.
type StateFull = FocusTracking Full
-- | A pattern synonym for the primary use case of the @FocusTracking@
-- transformer; using @Full@.
pattern StateFull :: FocusTracking Full a
pattern StateFull = FocusTracking Nothing Full
instance LayoutClass l Window => LayoutClass (FocusTracking l) Window where
description (FocusTracking _ child)
| (chDesc == "Full") = "StateFull"
| (' ' `elem` chDesc) = "FocusTracking (" ++ chDesc ++ ")"
| otherwise = "FocusTracking " ++ chDesc
where chDesc = description child
runLayout (W.Workspace i (FocusTracking mOldFoc childL) mSt) sr = do
mRealFoc <- gets (W.peek . windowset)
let mGivenFoc = W.focus <$> mSt
passedMSt = if mRealFoc == mGivenFoc then mSt
else (mOldFoc >>= \oF -> findZ (==oF) mSt) <|> mSt
(wrs, mChildL') <- runLayout (W.Workspace i childL passedMSt) sr
let newFT = if mRealFoc /= mGivenFoc then FocusTracking mOldFoc <$> mChildL'
else Just $ FocusTracking mGivenFoc (fromMaybe childL mChildL')
return (wrs, newFT)
handleMessage (FocusTracking mf childLayout) m =
(fmap . fmap) (FocusTracking mf) (handleMessage childLayout m)