哈斯克尔[字符]以字节串

Question

main :: IO() 
main = do 
    let a = ("teeeeeeeeeeeeest","teeeeeeeeeeeest") 
    b <- app a 
    print b 

的应用希望（字节字符串，字节字符串）不是（[字符]，[字符]） 我怎么能转换吗？

Answer 1

您可以转换String s到ByteString s的Data.ByteString.Char8.pack（或其懒惰ByteString版）如果您的String只包含ASCII值，或者你感兴趣的只是每个Char的后八位，

import qualified Data.ByteString.Char8 as C 
main :: IO() 
main = do 
    let a = ("teeeeeeeeeeeeest","teeeeeeeeeeeest") 
    b <- app $ (\(x,y) -> (C.pack x, C.pack y)) a 
    print b 

如果您的String包含非ASCII Char，并且您只对最后8位感兴趣，则需要其他编码，如Data.ByteString.UTF8.fromString。

Answer 2

你可以尝试：

import qualified Data.ByteString.Char8 as B --to prevent name clash with Prelude 
B.pack "Hello, world" 

很多有用的功能，可以在这里找到：

http://www.haskell.org/ghc/docs/latest/html/libraries/bytestring/Data-ByteString-Char8.html

你也可以使用Data.ByteString.Lazy.Char8 懒惰的字节串

http://hackage.haskell.org/packages/archive/bytestring/latest/doc/html/Data-ByteString-Lazy-Char8.html#v:pack