Johan Tibell wrote:
What *does* matter to the programmer is what encodings putStr and getLine use. AFAIK, they use "lower 8 bits of unicode code point" which is almost functionally equivalent to latin-1. Which is terrible! You should have to be explicit about what encoding you expect. Python 3000 does it right. Presumably there wasn't a sufficiently good answer available in time for haskell98. Will there be one for haskell prime ?
The I/O library needs an overhaul but I'm not sure how to do this in a backwards compatible manner which probably would be required for inclusion in Haskell'. One could, like Python 3000, break backwards compatibility. I'm not sure about the implications of doing this. Maybe introducing a new System.IO.Unicode module would be an option.
If one wants to keep the interface but change the semantics slightly one could define e.g. getChar as:
getChar :: IO Char getChar = getWord8 >>= decodeChar latin1
Assuming latin-1 is what's used now.
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. I did say 'lower 8 bits of unicode code point which is almost functionally equivalent to latin-1.' IIUC, it's latin-1 plus the two control-character ranges. There are no decoding errors for haskell98's getChar.
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.
Optionally, text I/O functions could default to the system locale setting.
That is a disastrous idea. Please read the other flamewars^Wdiscussions on this list about this subject :) One was started by a certain Johann Tibell :) http://haskell.org/pipermail/haskell-cafe/2007-September/031724.html http://haskell.org/pipermail/haskell-cafe/2007-September/032195.html Jules