Hi, I'm changing my CSV program to use ByteStrings, but I have problems with this: readCSVLine :: String -- line as String -> [String] -- line broken down into the value Strings readCSVLine = unfoldr builder where builder [] = Nothing builder xs = Just $ readField xs readField [] = ([],[]) readField (',':xs) = ([],xs) readField ('"':xs) = (field,rest) where (field,'"':rest) = break (== '"') xs So far, I have something like this - doesn't look too good to me, and doesn't compile: import qualified Data.ByteString as B import qualified Data.ByteString.Char8 as C8 type CSV = [[B.ByteString]] readCSVLine :: B.ByteString -- line as String -> [B.ByteString] -- line broken down into the value Strings readCSVLine = unfoldr builder where builder xs | xs == B.empty = Nothing | otherwise = Just $ readField xs readField xs | xs == B.empty = ([],[]) | B.head xs == ',' = ([], B.tail xs) | B.head xs == '"' = (field, B.tail rest) where field,rest) = B.break (== '"') xs I do not know how to compare a Word8 to a Char. Or maybe I don't need to? Regards Philip