On Thu, Jan 29, 2009 at 13:25, emmanuel.delaborde
<emmanuel.delaborde@cimex.com> wrote:
Hello
I have the following snippet :
----------------------------------------------------------
module Main where
import System.Environment (getArgs)
import Data.Digest.OpenSSL.MD5 (md5sum)
import Data.Digest.Pure.SHA (sha1, showDigest)
import qualified Data.ByteString as BS (readFile)
-- sha1 :: ByteString -> Digest
-- readFile :: FilePath -> IO ByteString
-- md5sum :: ByteString -> String
-- showDigest :: Digest -> String
checkHash :: String -> String -> String -> IO ()
checkHash codec hash file =
let f = case codec of
--"md5" -> md5sum
"sha1" -> showDigest . sha1
_ -> error "Codec must be md5 or sha1 !" in
BS.readFile file >>= \fileBS ->
let fileHash = f fileBS in
print (hash == fileHash)
main =
getArgs >>= \as ->
case as of
(codec:hash:file:_) -> checkHash codec hash file
_ -> usage
usage = print "checksum codec hash file"
----------------------------------------------------------
which fails to compile, this is the error I get :
checksum.hs:20:19:
Couldn't match expected type `Data.ByteString.Lazy.Internal.ByteString'
against inferred type `Data.ByteString.Internal.ByteString'
In the first argument of `f', namely `fileBS'
In the expression: f fileBS
In the definition of `fileHash': fileHash = f fileBS
it looks like (showDigest . sha1) expects Data.ByteString.Lazy.Internal.ByteString but gets Data.ByteString.Internal.ByteString
What can I do ?
Thanks
E.
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