In the crypto package, I have two functions > encrypt :: AESKey a => a -> Word128 -> Word128 > decrypt :: AESKey a => a -> Word128 -> Word128
which are exported. I also have > class (Bits a, Integral a) => AESKey a > > instance AESKey Word128 > instance AESKey Word192 > instance AESKey Word256 unexported which stops you using invalid keys. Someone has asked me to export AESKey as they want to write an explicit type signature for a function they are creating e.g. foo :: AESKey a => a -> Word128 -> Word128 foo x y = encrypt x y but this generates an error. Is there a way of allowing someone to use AESKey in a type signature but not allow them to declare new instances? Thanks, Dominic. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
