Re: [idn] call for comments for REORDERING

[Martin Duerst <duerst@w3.org>]

At 13:06 01/10/23 +0900, Soobok Lee wrote:

>----- Original Message -----
>From: "Mark Davis" <mark@macchiato.com>

> > 2. NFC does not combine ancient Hangul into syllables because there are no
> > syllables that have ancient Hangul in them. It does combine as many modern
> > Jamo as possible into syllables. That does not -- at all -- prevent the use
> > of NFC with ancient Hangul.
>
>Rendering problem remains unsolved.

What do you mean? Not all current implementations may be able to
render IV Fh correctly, but it's very easy to change the implementation
to do it correctly (assuming the application already renders
Im Vm Fh).


>"hangul  syllable ga + old jamo bansioth " != "old hangul syllable 
>ga+bansioth".

What kind of evidence do you have for the 'not equal'?

>There is defined no such false equivalence  in UTR15.

There is no character for "old hangul syllable ga+bansioth",
so in that sense indeed UTR 15 doesn't define such an equivalence.
What UTR 15 defines is the following equivalence

    Im Vm Fh <==> IV Fh
      (NFD)       (NFC)

This equivalence is clearly defined in UTR 15, in the same way
the following equivalences are defined:

    Im Vm Fm <==>   IV Fm   <==> IVF
     (NFD)     (intermediate)   (NFC)

UTR 15 doesn't have the concept of false equivalence.

>  Why rendering engine vendors should  make such false workarounds not
>recommended in UTC standards?

There is nothing false with making sure IV Fh is correctly
rendered. For some implementations, it may be a bit of a
workaround, but it's a very easy one.

Also UTR 15 (also called UAX 15) is an integral part of the Unicode
Standard. Please see http://www.unicode.org/unicode/reports/:

 >>>>
A Unicode Standard Annex (UAX) forms an integral part of the Unicode
Standard, carrying the same version number as the standard, but is
published as a separate document. Note that conformance to a version
of the Unicode Standard includes conformance to its Unicode Standard
Annexes.
 >>>>

It may be true that there is no part of The Unicode Standard that
explicitly says that IV Fh should be rendered as a single syllable
block, but there are many, many other details about rendering that
The Unicode Standard doesn't say explicitly.


>NFC is  dangerous for ancient hangul.

I wouldn't know why. If you know, please explain.


Regards,    Martin.