My thoughts on I/O, binary and chars can be summerised: 1) Produce a new WordN based IO library. 2) Character strings cannot be separated from their encodings (ie they must be encoded somehow - even if that encoding is ascii). I would approch this using parameterised phantom types, so for example you would have: data Ascii data Chr a = Char Then the encoding becomes explicit in the type system, but of course functions like equality on types cvan still be expressed generically: charEq :: Chr a -> Chr a -> Bool but of course, you must be comparing the same encodings (enforced by type system)! The phantom type could be used in IO, IE to define a new encodeing: data MyEncoding instance ChrToBinary MyEncoding where chrToBinary = ... instance BinaryToChr MyEncoding where binaryToChr = ... Keean.