许多类型的字符串(ByteString) [英] Many types of String (ByteString)
问题描述
我希望压缩我的应用程序的网络流量。根据(最新的?) b -2009 /rel =noreferrer>Haskell人气排行榜
$ b ByteString
s:
compress :: ByteString - > ByteString
解压缩:: ByteString - > ByteString
我正在使用常规字符串
它们也是 read
, show
和 Network.Socket 使用的数据类型。 code>:
sendTo :: Socket - >字符串 - > SockAddr - > IO Int
recvFrom :: Socket - > Int - > IO(String,Int,SockAddr)
所以要压缩我的字符串,我需要一些方法来转换字符串
转换为 ByteString
,反之亦然。
借助 hoogle 的帮助,我发现:
Data.ByteString.Char8 pack :: String - > ByteString
尝试使用它:
Prelude Codec.Compression.Zlib Data.ByteString.Char8>压缩(packboo)
< interactive>:1:10:
无法匹配预期的类型'Data.ByteString.Lazy.Internal.ByteString'
针对推断类型`ByteString'
在`compress'的第一个参数中,即`(packboo)'
在表达式中:compress(packboo)
在`it':it = compress(packboo)
失败,因为(?)不同类型的 ByteString
?
所以基本上:
- 有几种类型的
ByteString
?什么类型,为什么? - 将
字符串
s转换为ByteString $> c $ c> s?
顺便说一句,我发现它可以和
Data.ByteString.Lazy一起工作。 Char8
的 ByteString
,但我仍然很感兴趣。 有两种字节串:strict(在 Data.Bytestring.Internal )和lazy(在 Data.Bytestring.Lazy.Internal )。正如您发现的那样,zlib使用懒惰的字节串。
I wish to compress my application's network traffic.
According to the (latest?) "Haskell Popularity Rankings", zlib seems to be a pretty popular solution. zlib's interface uses ByteString
s:
compress :: ByteString -> ByteString
decompress :: ByteString -> ByteString
I am using regular String
s, which are also the data types used by read
, show
, and Network.Socket
:
sendTo :: Socket -> String -> SockAddr -> IO Int
recvFrom :: Socket -> Int -> IO (String, Int, SockAddr)
So to compress my strings, I need some way to convert a String
to a ByteString
and vice-versa.
With hoogle's help, I found:
Data.ByteString.Char8 pack :: String -> ByteString
Trying to use it:
Prelude Codec.Compression.Zlib Data.ByteString.Char8> compress (pack "boo")
<interactive>:1:10:
Couldn't match expected type `Data.ByteString.Lazy.Internal.ByteString'
against inferred type `ByteString'
In the first argument of `compress', namely `(pack "boo")'
In the expression: compress (pack "boo")
In the definition of `it': it = compress (pack "boo")
Fails, because (?) there are different types of ByteString
?
So basically:
- Are there several types of
ByteString
? What types, and why? - What's "the" way to convert
String
s toByteString
s?
Btw, I found that it does work with Data.ByteString.Lazy.Char8
's ByteString
, but I'm still intrigued.
There are two kinds of bytestrings: strict (defined in Data.Bytestring.Internal) and lazy (defined in Data.Bytestring.Lazy.Internal). zlib uses lazy bytestrings, as you've discovered.
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