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|
{-|
Module : System.IO.Terminal.IO
Copyright : (c) UU, 2019
License : MIT
Maintainer : Tom Smeding
Stability : experimental
Portability : POSIX, macOS, Windows
Extra terminal management utility functions. This module basically extends
the @ansi-terminal@ package.
-}
module System.IO.Terminal.IO
(queryTermSize
-- ,withWinchHandler
,toAlternateScreen
,fromAlternateScreen)
where
-- import Foreign.C.Types
import qualified System.Console.Terminal.Size as TS
-- import System.Exit
import System.IO
-- import System.Posix.Signals
-- sigWINCH :: CInt
-- sigWINCH = 28
-- | Request the current terminal size from the terminal. Probably not very
-- fast.
queryTermSize :: IO (Int, Int)
queryTermSize = TS.size >>= \case
Just win -> return (TS.width win, TS.height win)
Nothing -> error "Cannot get terminal size"
-- withWinchHandler :: IO () -> IO a -> IO a
-- withWinchHandler h act = do
-- prevh <- installHandler sigWINCH (Catch h) Nothing
-- case prevh of
-- Default -> return ()
-- Ignore -> return ()
-- _ -> die "ERROR: A signal handler was already installed for the WINCH signal!"
-- res <- act
-- _ <- installHandler sigWINCH prevh Nothing
-- return res
-- | Switch to the \"alternate screen\", if the terminal supports it.
toAlternateScreen :: IO ()
toAlternateScreen = putStr "\x1B[?1049h" >> hFlush stdout
-- | Switch from the \"alternate screen\" back to the normal buffer, if the
-- terminal supports it.
fromAlternateScreen :: IO ()
fromAlternateScreen = putStr "\x1B[?1049l" >> hFlush stdout
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