haskell [char] 到字节串

Question

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

应用程序期望 (bytestring,bytestring) 不是 ([char],[char])
我该如何转换它？

Answer 1

您可以转换 String转至 ByteString s 与 Data.ByteString.Char8.pack (或懒惰的 ByteString 版本)如果您的 String只包含 ASCII 值，或者您只对每个 Char 的最后八位感兴趣,

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 s 并且您只对最后八位感兴趣，您将需要一些其他编码，例如 Data.ByteString.UTF8.fromString .