如何防止输入被冲刷成输出? [英] How to prevent inputs being flushed into output?

问题描述

我在Ubuntu上.当我在终端上运行ghci并执行以下操作时:

I'm on Ubuntu. When I run ghci on Terminal and do this:

Prelude Control.Monad System.IO> forever $ getChar >>= print

结果是这样的:

a'a'
b'b'
C'C'
%'%'
\'\\'
1'1'
''\''
"'"'
^X'\CAN'
^?'\DEL'
^CInterrupted.

也就是说，我在键盘上输入的字符将被刷新到输出中.如何防止这种情况并且只将print作为作者?

That is, the characters I type in my keyboard are being flushed into output. How can I prevent this and have only print as the writer?

推荐答案

为防止输入刷新到输出(或回显")中，请使用

To prevent input being flushed into the output (or "echoed"), use hSetEcho stdin False.

Prelude> import System.IO
Prelude System.IO> import Control.Monad
Prelude System.IO Control.Monad> hSetEcho stdin False
Prelude System.IO Control.Monad> forever $ getChar >>= print
'a'
'\n'
'b'
'c'

这可用于执行输入密码之类的事情.

This can be used to do things like read in a password.

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