Move MODULE files out of individual project directories into a

[sgt/charset] / README

This subdirectory contains a general character-set conversion
library, used in Timber, and available for use in other software if
it should happen to be useful.

I intend to use this same library in other programs at some future
date. (A cut-down version of it is already in use in some ports of
PuTTY.) It is therefore a _strong_ design goal that this library
should remain perfectly general, and not tied to particulars of
Timber. It must not reference any code outside its own subdirectory;
it should not have Timber-specific helper routines added to it
unless they can be documented in a general manner which might make
them useful in other circumstances as well.

There are some multibyte character encodings which this library does
not currently support. Those that I know of are:

 - Johab. There is no reason why we _shouldn't_ support this, but it
   wasn't immediately necessary at the time I did the initial
   coding. If anyone needs it, it shouldn't be too hard. The Unicode
   mapping table for the encoding is available at
   http://www.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/KSC/JOHAB.TXT

 - ISO-2022-JP-1 (RFC 2237), and ISO-2022-JP-2 (RFC 1554). These
   should be even easier if required - we already have the ISO 2022
   machinery in place, and support all the underlying character
   sets.

 - ISO-2022-CN and ISO-2022-CN-EXT (RFC 1922), and EUC-TW. These
   encodings depend on the CNS 11643-1992 character set. Mapping
   table data for this set is available from unicode.org, but only
   in the Unihan database
   ftp://ftp.unicode.org/Public/UNIDATA/Unihan.zip

 - The Hong Kong (HKSCS) extension to Big5. Again, mapping tables
   are available in the Unihan database.

 - Other Big Five extensions, which I don't have mapping tables for
   at all.