GHCi中的Haskell语句被中断似乎破坏了cmd [英] Haskell statements in GHCi being interrupted seems to break cmd

问题描述

我只是从Haskell开始，然后在cmd中玩GHCi。在尝试在PPCG上看到的内容后，我遇到了一个问题。每当我用Control-C中断 fix 时，所有操作都会死亡：

  C ：\用户\Scrooble> ghci 
 GHCi，版本8.2.1：http://www.haskell.org/ghc/：？寻求帮助
 Prelude>导入Data.Function 
前奏Data.Function>修复（\x-> x + 1）
 In ^ tCerrupte 
 d。 
 C：\用户\Scrooble> Prelude Data.Function>退出
  

（挂起）

code> ^ 和 C 是我的键盘中断。 退出也是我的。

已损坏是对！到底是怎么回事？！我似乎已经退出了GHCi。当我中断退出（再次提示 Prelude Data.Function> ）和：q时，它有时会关闭，有时会再次提示我；但是，发生这种情况时，我所有命令的第一个字符都会被忽略！

  C：\Users\Scrooble> exit 
'xit'不被识别为内部或外部命令，
可操作程序或批处理文件。 
  

0.o

我一个人在这？是否有修复程序（ha）（不是不做愚蠢的事情）？

HP ProBook 4535s（带有Windows） 7 Professional，64位。 AMD A4-3300M APU处理器。

在PowerShell中也是如此。在Git Bash中，我中断 fix 后窗口冻结。

编辑：

我现在在打断其他无限递归时就遇到了这种情况，例如我的mergesort（哇！）并没有将单例视为必须排序。

解决方案

似乎您正在运行已安装Haskell平台在Windows上。我习惯了这一点，但是如今，我通过 Stack 运行所有内容，因此我可能会错误地记住以下内容。 / p>

IIRC，但是，当您尝试在Windows中运行 ghci 时，它将显式显示警告消息，即 ghci 在Windows上的break命令存在问题，因此您应该通过批处理命令 ghcii.bat 运行GHCi。

当我使用Haskell平台时，我总是与 ghcii.bat 一起运行，通常没有问题。我一直在Git Bash中使用Haskell，这是Windows上的默认CLI，所以这也可能是一个决定性因素。

这些天，我在Windows 10，以及在Git Bash中，我无法重现该问题：

  $ stack ghci 
 Prelude> ：m + Data.Function 
前奏Data.Function>修复（\x-> x + 1）
中断。 
 Prelude Data.Function> 
  

Interrupted。行是我打到的地方 Ctrl + C 。当我这样做时， fix 的阻止应用程序立即退出，REPL已准备好采取行动。

I'm just beginning with Haskell and playing around with GHCi in cmd. After trying out something I saw on PPCG, I ran into an issue. Whenever I interrupt fix with control-C, everything dies:

C:\Users\Scrooble>ghci
GHCi, version 8.2.1: http://www.haskell.org/ghc/  :? for help
Prelude> import Data.Function
Prelude Data.Function> fix (\x -> x + 1)
In^tCerrupte
d.
C:\Users\Scrooble>Prelude Data.Function> exit

(hangs)

The ^ and C were my keyboard interrupt. The exit is mine as well.

Cerrupted is right! What is going on?! I seem to have halfway exited GHCi. When I interrupt the exit (prompt is Prelude Data.Function> again) and :q it, cmd sometimes just closes and sometimes prompts me with C:\Users\Scrooble once more; however, when this happens, the first character of all my commands is ignored!

C:\Users\Scrooble>exit
'xit' is not recognized as an internal or external command,
operable program, or batch file.

0.o

Am I alone in this? Is there a fix (ha) (other than not doing stupid things)?

HP ProBook 4535s, with Windows 7 Professional, 64-bit. AMD A4-3300M APU processor.

The same happens in PowerShell as well. In Git Bash, the window freezes after I interrupt the fix.

Edit:

I've now experienced this when interrupting other infinite recursion, like my mergesort that (whoops!) didn't treat singletons as necessarily sorted.

解决方案

It looks like you're running Haskell platform installed on Windows. I used to to that, but these days I run everything through Stack, so I may remember the following incorrectly.

IIRC, though, when you attempt to run ghci in Windows, it explicitly prints a warning that ghci is known to have problems with break commands on Windows, and that you should instead run GHCi via the batch command ghcii.bat.

Back when I used the Haskell platform, I always ran with ghcii.bat, and typically didn't have those problems. I've always used Haskell from within Git Bash, which is my default CLI on Windows, so that could be a determining factor as well.

These days I use Stack on Windows 10, and from within Git Bash, I can't reproduce the problem:

$ stack ghci
Prelude> :m +Data.Function
Prelude Data.Function> fix (\x -> x + 1)
Interrupted.
Prelude Data.Function>

The Interrupted. line is where I hit Ctrl+C. When I did that, the blocking application of fix immediately exited, and the REPL was ready for action.

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