On Dec 24, 2007 11:55 AM, Paulo J. Matos <[EMAIL PROTECTED]> wrote: > On Dec 23, 2007 12:44 PM, Isaac Dupree <[EMAIL PROTECTED]> wrote: > > > > -- this should work too > > parseHeader3 :: BS.ByteString -> Maybe (Int, Int) > > --note accurate type signature, which helps us use Maybe failure-monad, > > --although losing your separate error messages > > Oh gee, I just noticed that my type sig is in fact not correct. How > come GHC doesn't complain? > > > parseHeader3 bs = do > > (x, rest) <- BS.readInt $ BS.dropWhile (not . isDigit) bs > > (y, _) <- BS.readInt $ BS.dropWhile (not . isDigit) rest > > return (x, y) > > What happens then if the first BS.readInt return Nothing??? >
Ok, got it, I'm not returning a maybe. That's it then. Still, the first question remains... what happens to (x, rest) if BS.readInt returns Nothing. -- Paulo Jorge Matos - pocm at soton.ac.uk http://www.personal.soton.ac.uk/pocm PhD Student @ ECS University of Southampton, UK _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
