On 29 Jan 2009, at 16:10, beginners-request@haskell.org wrote:
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I didn't compile, but, by the looks of it, I would change
import qualified Data.ByteString as BS (readFile)
for
import qualified Data.ByteString.Lazy as BS (readFile)
as it seems sha1 needs a lazy bytestring
Thanks ! It compiles now but brings me to my real problem :) If I uncomment this line "md5" -> md5sum I get the following : ------ module Main where import System.Environment (getArgs) import Data.Digest.OpenSSL.MD5 (md5sum) import Data.Digest.Pure.SHA (sha1, showDigest) import qualified Data.ByteString.Lazy 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 now fails to compile with this error : checksum.hs:17:22: Couldn't match expected type `Data.ByteString.Internal.ByteString' against inferred type `Data.ByteString.Lazy.Internal.ByteString' In the expression: showDigest . sha1 In a case alternative: "sha1" -> showDigest . sha1 In the expression: case codec of { "md5" -> md5sum "sha1" -> showDigest . sha1 _ -> error "Codec must be md5 or sha1 !" } How can I both use md5sum and sha1 when one use a lazy ByteString end the other one does not ? Thanks E -- Emmanuel Delaborde Web Technologist Cimex 53-55 Scrutton Street, London UK, EC2A 4PJ T: +44 (0)20 7324 7780 F: +44 (0)20 7324 7781 http://www.cimex.com ----------------------------------------------------------------------------------------------- This e-mail (and any attachments) is confidential and may contain personal views which are not the views of Cimex Media Ltd and any affiliated companies, unless specifically stated. It is intended for the use of the individual or group to whom it is addressed. If you have received it in error, please delete it from your system, do not use, copy or disclose the information in any way nor act in reliance on it and please notify postmaster@cimex.com A company registered in England Wales. Company Number 03765711 Registered Office : The Olde Bakehouse, 156 Watling Street East, Towcester, Northants NN12 6DB This email was scanned by Postini, the leading provider in Managed Email Security.