src/Internal/Logger.hs


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module Internal.Logger where

import XMonad
import qualified XMonad.Util.ExtensibleState as XS
import System.IO

data LoggerState =
  LoggerState {
    logHandle :: Maybe Handle
  }

instance Read LoggerState where
  readsPrec i s = map (\(_, s) -> (LoggerState Nothing, s)) (readsPrec i s :: [((), String)])

instance Show LoggerState where
  show _ = show ()

instance ExtensionClass LoggerState where
  initialValue = LoggerState Nothing

logs :: String -> X ()
logs s = do
  LoggerState handle' <- XS.get

  handle <-
    case handle' of
      Nothing -> do
        handle <- io $ openFile "/tmp/xmonad.log" AppendMode
        XS.put $ LoggerState (Just handle)
        return handle

      Just h -> return h
  
  io $ do
    hPutStrLn handle s
    hFlush handle