Subject: Re: Big5 != CNS

From: John Delacour <[email-masked]>
Date: Thu, 28 Apr 1994 23:17:01 +0100

Roland Wang writes:

>CNS is a character set. It's implementation independent. Big5 has two
>meanings,
>character set (implementation independent) and encoding scheme
>(implementation
>dependent). When we talk about character sets, CNS is a super set of Big5
>(CNS has much more characters than Big5).

>From everything I've seen in the way of tables and things I've read, CNS
11643-1986 contains 13,051 characters and Big5 13,053 characters, including
all the non-Hanzi characters, so perhaps != should be replaced by !quite=

      John

One character that fascinates me is this one:-

0xC94A  0xFA0C  # CJK COMPATIBILITY IDEOGRAPH-FA0C

Does anyone know what this signifies?

I append the introduction to the Unicode Big5 table (from FTP://unicode.org:-

______________________

Name:             BIG5 to Unicode table (complete)
Unicode version:  1.1
Table version:    0.0d3
Table format:     Format A
Date:             11 February 1994
Authors:          Glenn Adams <[email-masked]>
John H. Jenkins <[email-masked]>

General notes:

This table contains the data Metis and Taligent currently have on how
BIG5 characters map into Unicode.

WARNING!  It is currently impossible to provide round-trip compatibility
between BIG5 and Unicode.

A number of characters are not currently mapped because
of conflicts with other mappings.  They are as follows:

BIG5        Description                    Comments

0xA15A      SPACING UNDERSCORE             duplicates A1C4
0xA1C3      SPACING HEAVY OVERSCORE        not in Unicode
0xA1C5      SPACING HEAVY UNDERSCORE       not in Unicode
0xA1FE      LT DIAG UP RIGHT TO LOW LEFT   duplicates A2AC
0xA240      LT DIAG UP LEFT TO LOW RIGHT   duplicates A2AD
0xA2CC      HANGZHOU NUMERAL TEN           conflicts with A451 mapping
0xA2CE      HANGZHOU NUMERAL THIRTY        conflicts with A4CA mapping

We currently map all of these characters to U+FFFD REPLACEMENT CHARACTER.
It is also possible to map these characters to their duplicates, or to
the user zone.

Notes:

1. In addition to the above, there is some uncertainty about the
mappings in the range C6A1 - C8FE, and F9DD - F9FE.  The ETEN
version of BIG5 organizes the former range differently, and adds
additional characters in the latter range.  The correct mappings
these ranges need to be determined.

2.  There is an uncertainty in the mapping of the Big Five character
0xA3BC.  This character occurs within the Big Five block of tone marks
for bopomofo and is intended to be the tone mark for the first tone in
Mandarin Chinese.  We have selected the mapping U+02C9 MODIFIER LETTER
MACRON (Mandarin Chinese first tone) to reflect this semantic.
However, because bopomofo uses the absense of a tone mark to indicate
the first Mandarin tone, most implementations of Big Five represent
this character with a blank space, and so a mapping such as U+2003 EM SPACE
might be preferred.

Format:  Three tab-separated columns
Column #1 is the BIG5 code (in hex as 0xXXXX)
Column #2 is the Unicode (in hex as 0xXXXX)
Column #3  is the Unicode name (follows a comment sign, '#')
The official names for Unicode characters U+4E00
to U+9FA5, inclusive, is "CJK UNIFIED IDEOGRAPH-XXXX",
where XXXX is the code point.  Including all these
names in this file increases its size substantially
and needlessly.  The token "<CJK>" is used for the
name of these characters.  If necessary, it can be
expanded algorithmically by a parser or editor.

The entries are in BIG5 order

Any comments or problems, contact <[email-masked]>