Copyright	(C) 2016-2017 Ryan Scott
License	BSD-style (see the file LICENSE)
Maintainer	Ryan Scott
Stability	Provisional
Portability	Portable
Safe Haskell	Safe
Language	Haskell2010

System.IO.Echo

Contents

Public interface
Alternative interface

Description

Exports functions that handle whether or not terminal input is handled in a way that should be portable across different platforms and consoles.

Synopsis

withoutInputEcho :: IO a -> IO a
bracketInputEcho :: IO a -> IO a
getInputEchoState :: IO EchoState
setInputEchoState :: EchoState -> IO ()
data EchoState
echoOff :: EchoState
echoOn :: EchoState
getInputEcho :: IO Bool
setInputEcho :: Bool -> IO ()

Public interface

withoutInputEcho :: IO a -> IO a #

Perform a computation with the terminal's input echoing disabled. Before running the computation, the terminal's input EchoState is saved, and the saved EchoState is restored after the computation finishes.

withoutInputEcho action = bracketInputEcho (setInputEchoState echoOff >> action)

bracketInputEcho :: IO a -> IO a #

Save the terminal's current input EchoState, perform a computation, restore the saved EchoState, and then return the result of the computation.

bracketInputEcho action = bracket getInputEchoState setInputEchoState (const action)

getInputEchoState :: IO EchoState #

Return the terminal's current input EchoState.

setInputEchoState :: EchoState -> IO () #

Set the terminal's input EchoState.

data EchoState #

A representation of the terminal input's current echoing state. Example values include echoOff and echoOn.

Instances

Eq EchoState #
Instance details Defined in System.IO.Echo.Internal Methods (==) :: EchoState -> EchoState -> Bool # (/=) :: EchoState -> EchoState -> Bool #
Ord EchoState #
Instance details Defined in System.IO.Echo.Internal Methods compare :: EchoState -> EchoState -> Ordering # (<) :: EchoState -> EchoState -> Bool # (<=) :: EchoState -> EchoState -> Bool # (>) :: EchoState -> EchoState -> Bool # (>=) :: EchoState -> EchoState -> Bool # max :: EchoState -> EchoState -> EchoState # min :: EchoState -> EchoState -> EchoState #
Show EchoState #
Instance details Defined in System.IO.Echo.Internal Methods showsPrec :: Int -> EchoState -> ShowS # show :: EchoState -> String # showList :: [EchoState] -> ShowS #

echoOff :: EchoState #

Indicates that the terminal's input echoing is (or should be) off.

echoOn :: EchoState #

Indicates that the terminal's input echoing is (or should be) on.

Alternative interface

getInputEcho :: IO Bool #

Return whether the terminal's echoing is on (True) or off (False).

Note that while this works on MinTTY, it is not as efficient as getInputEchoState, as it involves a somewhat expensive substring computation.

setInputEcho :: Bool -> IO () #

Set the terminal's echoing on (True) or off (False).