The benefit would be that if the input is not in latin-1 an exception could be thrown rather than returning a Char representing the wrong Unicode code point.
I'm not sure what you mean here. All 256 possible values have a meaning.
You're of course right. So we don't have a problem here. Maybe I was thinking of an encoding (7-bit ASCII?) where some of the 256 values are invalid.
My proposal is for I/O functions to specify the encoding they use if they accept or return Chars (and Strings). If they deal in terms of bytes (e.g. socket functions) they should accept and return Word8s.
I would be more inclined to suggest they default to a particular well understand encoding, almost certainly UTF8. Another interface could give access to other encodings.
That might be a good option. However, it would be nice if beginners could write simple console programs using System.IO and have them work correctly even if their system's encoding is not byte compatible with UTF-8. People who do I/O over the network etc. need to be more careful and should specify the encoding used. How would a UTF-8 default work on different Windows versions?
Optionally, text I/O functions could default to the system locale setting.
That is a disastrous idea.
I'm not sure about that as long as decode is called on the input to make sure that it's a valid encoding given the input bytes. Same point as above. What I would like to avoid is having to write: main = do putStrLn systemLocalEncoding "What's your name?" name <- getLine systemLocalEncoding putStrLn systemLocalEncoding $ "Hi " ++ name ++ "!" I guess we could solve this by putting the functions in different modules: System.IO -- requires explicit encoding System.IO.DefaultEncoding -- implicit use of system locale setting And have the modules export the same functions. Another option would be to include the fact that encoding is implied in the name of the function. Maybe we should start by giving some type signatures and function names. That often helps my thinking. I'll try to write something down when I get home from work. -- Johan