mirror of
https://github.com/xmonad/xmonad-contrib.git
synced 2025-07-26 09:41:52 -07:00
528b9d9fde
Move the function from X.U.DebugWindow, where it was defined already. This is a safe version of getWindowAttributes, returning a Maybe instead of throwing an exception, in case the window attributes could not be retrieved.
83 lines
2.5 KiB
Haskell
83 lines
2.5 KiB
Haskell
{-# LANGUAGE BangPatterns #-}
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{-# LANGUAGE LambdaCase #-}
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--------------------------------------------------------------------
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-- |
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-- Module : XMonad.Prelude
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-- Description : Utility functions and re-exports.
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-- Copyright : slotThe <soliditsallgood@mailbox.org>
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-- License : BSD3-style (see LICENSE)
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--
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-- Maintainer : slotThe <soliditsallgood@mailbox.org>
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--
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-- Utility functions and re-exports for a more ergonomic developing
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-- experience. Users themselves will not find much use here.
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--
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--------------------------------------------------------------------
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module XMonad.Prelude (
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module Exports,
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fi,
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chunksOf,
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(.:),
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(!?),
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NonEmpty((:|)),
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notEmpty,
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safeGetWindowAttributes,
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) where
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import Foreign (alloca, peek)
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import XMonad
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import Control.Applicative as Exports
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import Control.Monad as Exports
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import Data.Bool as Exports
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import Data.Char as Exports
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import Data.Foldable as Exports
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import Data.Function as Exports
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import Data.Functor as Exports
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import Data.List as Exports
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import Data.Maybe as Exports
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import Data.Monoid as Exports
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import Data.Traversable as Exports
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import Data.List.NonEmpty (NonEmpty((:|)))
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import GHC.Stack
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-- | Short for 'fromIntegral'.
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fi :: (Integral a, Num b) => a -> b
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fi = fromIntegral
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-- | Given a maximum length, splits a list into sublists
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--
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-- >>> chunksOf 5 (take 30 $ repeat 'a')
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-- ["aaaaa","aaaaa","aaaaa","aaaaa","aaaaa","aaaaa"]
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chunksOf :: Int -> [a] -> [[a]]
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chunksOf _ [] = []
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chunksOf i xs = chunk : chunksOf i rest
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where !(chunk, rest) = splitAt i xs
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-- | Safe version of '(!!)'.
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(!?) :: [a] -> Int -> Maybe a
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(!?) xs n | n < 0 = Nothing
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| otherwise = listToMaybe $ drop n xs
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-- | Multivariant composition.
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--
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-- > f .: g ≡ (f .) . g ≡ \c d -> f (g c d)
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(.:) :: (a -> b) -> (c -> d -> a) -> c -> d -> b
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(.:) = (.) . (.)
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-- | 'Data.List.NonEmpty.fromList' with a better error message. Useful to
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-- silence GHC's Pattern match(es) are non-exhaustive warning in places where
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-- the programmer knows it's always non-empty, but it's infeasible to express
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-- that in the type system.
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notEmpty :: HasCallStack => [a] -> NonEmpty a
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notEmpty [] = error "unexpected empty list"
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notEmpty (x:xs) = x :| xs
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-- | A safe version of 'Graphics.X11.Extras.getWindowAttributes'.
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safeGetWindowAttributes :: Window -> X (Maybe WindowAttributes)
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safeGetWindowAttributes w = withDisplay $ \dpy -> io . alloca $ \p ->
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xGetWindowAttributes dpy w p >>= \case
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0 -> pure Nothing
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_ -> Just <$> peek p
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