Question

capslocker.hs有以下代码：

import Control.Monad  
import Data.Char  
main = forever $ do  
    putStr "Give me some input: "  
    l <- getLine  
    putStrLn $ map toUpper l

haiku.txt有以下内容：

I'm a lil' teapot  
What's with that airplane food, huh?  
It's so small, tasteless

在终端中，我能够：

optimight@optimight:~$ cat haiku.txt  
I'm a lil' teapot  
What's with that airplane food, huh?  
It's so small, tasteless

而且：

optimight@optimight:~$ cat haiku.txt | ./capslocker  
Give me some input: I'M A LIL' TEAPOT  
Give me some input: WHAT'S WITH THAT AIRPLANE FOOD, HUH?  
Give me some input: IT'S SO SMALL, TASTELESS  
Give me some input: capslocker: <stdin>: hGetLine: end of file

如何在emacs23中测试相同（在终端中完成） - haskell模式？请指导。

请注意，在emacs - haskell模式中，我尝试过以下操作：

GHCi, version 7.4.1: http://www.haskell.org/ghc/  :? for help  
Loading package ghc-prim ... linking ... done.  
Loading package integer-gmp ... linking ... done.  
Loading package base ... linking ... done.  
Prelude> :load "/home/optimight/capslocker.hs"  
[1 of 1] Compiling Main      ( /home/optimight/capslocker.hs, interpreted )  
Ok, modules loaded: Main.  
*Main> cat haiku.txt | ./capslocker  
<interactive>:3:15: parse error on input `|'   
*Main>

Answer 1

在ghci提示符下，您可以通过添加:!前缀来调用shell命令。

*Main> :! cat haiku.txt | ./capslocker

它应该在emacs中工作相同。

如何 - 使用emacs - haskell模式将一个程序的输出传递给另一个程序的输入（capslocker）？

1 个答案: