🚀 go-pugleaf

Mark O. Chadwick <ncc1701@madoka.its.rpi.edu> writes:
|
|   The following answers are based off of second-hand info, and possibly
|   not correct due to faulty memory, so take with a grain of salt :-)

Oh, please, we have enough of nth-hand information about things already.

|   mskuhn@immd4.informatik.uni-erlangen.de (Markus Kuhn) writes:
|
|   >- How is ISO 10646 structured? Is it a 16 or a 32 bit character set?

Both.  You select which with an escape code or a "signature".  I think
16 bits is going to win the market hands down.  Chinese, Japanese and
Korean was "unified", and requires about 36000 bit combinations (or code
points in IBM-speak).

There's also a transformation code defined which makes it possible to
use only the bit combinations dedicated for graphic characters in other
ISO standards, corresponding to the 8-bit integers 32 through 126 and
160 through 255.  This is strictly a transformation code, though, and
internal representation should be the real 16-bit character numbers.

|   >- What subsets are defined in ISO 10646?

A number of subsets are defined, and can be requested with an escape
code.  I have only the DIS list, and more may be defined.

|   >- How does it relate with US-ASCII, ISO Latin 1 and Unicode?

US ASCII is found at positions 00xy (hex), where 0 <= x <= 7, and 0 <= y
<= F.  ISO Latin 1 is found at positions 00xy, where A <= x <= F, and y
as above.  Unicode and ISO 10646 have merged, and Unicode 1.x (x >= 1,
don't remember which) will be the same as ISO 10646.

|   >- What's the standard's status today (DIS?)? When will it be published
|   >  officially?

It passed the DIS to IS vote.  I don't know when it will be published
officially.

|   >- What requirements are there for application programs (editors, etc.)
|   >  and libraries if they what to handle ISO 10646 files?

I'm not qualified to reply to that.  (In other words, I'm still trying
to figure it out, and don't want to confuse anybody.)

|   >- Has anyone already written a short ISO 10646 FAQ list with answers?

I'm tempted, and will probably end up doing it, but don't hold your
breath.

|   >- What else should a computer science student know about ISO 10646
|   >  in the future?

Acquire it, or wait for my book on character sets and character data
representation, but you should definitely not hold your breath for that
one to come out!

|   No idea.  However, it will present some difficulties for programmers
|   since they (especially non-Asian ones) tend to think of strings
|   as being made up of 8 bit entities.  The Japanese and Chinese already
|   use 16 bits, so they might have somewhat an easier time converting

Programmers should generally be able to switch from "think 8 bits" to
"think 16 bits", but there are lots of nits and grits to get right, and
I'm still researching this topic.  The use of combining characters,
where you use a sequence of characters to make up one "character", will
pose _interesting_ problems.  The Chinese and Japanese have actually
been using two septets (for a total of fourteen bits), and this is a
true 16-bit coded character set, so they will face problems both with
the encoding, and the bit combinations corresponding to an individual
ideographic character.

|   I also heard there might be prefix codes to determine the language
|   to be selected.  I'm not sure how that'll be implemented though--does
|   that mean there will be lots of holes in the 32 bit character map?

The language chosen affects such things as collating sequences and such.
You can't use the subset mechanism for this purpose, and language is
really not the province of character sets in the first place.  There are
a lot of holes in the 16-bit character set.  The coded character set is
defined for 0000xxxx (0 <= x <= F), only.

Language would probably have to be provided as part of the system
environment by other means.  Standard C and POSIX provide the "locale"
mechanism, which may or may not be sufficient for this purpose.

The above represents the best of my knowledge and comes from reading the
ISO working papers on the standard development, voting on it, reading
the ISO10646 mailing list and its archives, and I have no reason to
think any of it is wrong or that I misrepresent ISO 10646.  For the one,
true answer, though, consult the standard.  I'm sure comp.std.internat
will be the choice newsgroup to announce its availability.

Best regards,
</Erik>
--
Erik Naggum             |  ISO  8879 SGML     |      +47 295 0313
                        |  ISO 10744 HyTime   |
<erik@naggum.no>        |  ISO 10646 UCS      |      Memento, terrigena.
<enag@ifi.uio.no>       |  ISO  9899 C        |      Memento, vita brevis.