GHC 10.0.0.20260917 · lts/ghc-10.0.x · 8fef28d · 2026-11-02
Moduleecho-0.1.4Haskell2010
Exports functions that handle whether or not terminal input is handled in a way that should be portable across different platforms and consoles.
Unlike System.IO.Echo, this module exports internal functionality which, if used improperly, can lead to runtime errors. Make sure to read the documentation beforehand!
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)
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)
Return the terminal's current input EchoState.
Set the terminal's input EchoState.
Indicates that the terminal's input echoing is (or should be) off.
Indicates that the terminal's input echoing is (or should be) on.
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.
A representation of the terminal input's current echoing state. Example values include echoOff and echoOn.
MinTTY STTYSettingsThe argument to (or value returned from) an invocation of the stty
command-line utility. Most POSIX-like shells have stty, including
MinTTY on Windows. Since neither hGetEcho nor hSetEcho work on
MinTTY, when getInputEchoState runs on MinTTY, it returns a value
built with this constructor.
However, native Windows consoles like cmd.exe or PowerShell do not
have stty, so if you construct an EchoState with this constructor
manually, take care not to use it with a native Windows console.
DefaultTTY BoolSettings used to configure the stty command-line utility.
Return all of stty's current settings in a non-human-readable format.
This function is not very useful on its own. Its greater purpose is to provide a compact STTYSettings that can be fed back into setInputEchoState.
Create an stty process, wait for it to complete, and return its output.
Is the current process attached to a MinTTY console (e.g., Cygwin or MSYS)?