George Russell wrote:

...

OTOH, existing implementations (at least GHC and Hugs) currently read and write "8-bit binary", i.e. characters 0-255 get read and written "as-is" and anything else breaks, and changing that would probably break a fair amount of existing code.

The binary library I posted to the libraries list:

http://haskell.org/pipermail/libraries/2003-June/001227.html

which is for GHC, does this properly. All characters are encoded using a standard encoding for unsigned integers, which uses the bottom 7 bits of each character as data, and the top bit to signal that the encoding is not yet complete. Characters 0-127 (which include the standard ASCII ones) get encoded as themselves.

This is similar to UTF-8; however, UTF-8 is a standard format which can be read and written by a variety of other programs. If we want a mechanism for encoding arbitrary Haskell strings as octet lists, and we have a free choice as to the encoding, UTF-8 is definitely the way to go. However, that isn't the issue which was being discussed in this thread. The issue is that we need a standard mechanism for reading and writing *octets*, so that Haskell programs can communicate with the rest of the world. As things stand, if you want to read/write files which were written by another program, you have to rely either upon extensions, or upon behaviour which isn't mandated by the report. -- Glynn Clements <glynn.clements@virgin.net>