Subject: Re: [idn] rename ToUnicode?

From: Dan Oscarsson <[email-masked]>
Date: Mon, 13 May 2002 08:43:36 +0200

Adam M. Costello wrote:

>Keld Jørn Simonsen <[email-masked]> wrote:
>
>> I don't think that ToUnicode is the correct name, as it is really
>> 10646 that it is defined for.
>
>The difference between ISO-10646 and Unicode is not relevant here.
>Both use the same table that maps between code points and characters.
>The difference (as I understand it) is that Unicode defines lots of
>additional information about the characters and how to handle them,
>while ISO-10646 is little more than a table and some encoding forms.

IETF should refer to official standards organisations if possible.

So ToUCS is better than ToUnicode.

   Dan

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From: "Adam M. Costello" <[email-masked]>
Date: Mon, 13 May 2002 10:55:53 +0000

> IETF should refer to official standards organisations if possible.

Correct me if I'm wrong, but I think ISO-10646 does not define
normalization forms or case folding.  Therefore IDNA cannot avoid
referencing Unicode.  Once we reference Unicode, there's no point in
referencing ISO-10646, because it doesn't contain anything of interest
that isn't already in Unicode.

Wouldn't it be ironic for the IETF to dismiss another standard-producing
organization as not being official enough?  Hasn't that same charge
historically been made against the IETF itself?

For practical reasons, isn't it preferable to reference a spec that's
easily available?  The Unicode standard is on the web for anyone to view
at no charge.  Is the same true of ISO-10646?

AMC

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From: Keld Jørn Simonsen <[email-masked]>
Date: Mon, 13 May 2002 13:30:16 +0200

> that isn't already in Unicode.

ISO does define case folding, and ISO says that given a specific
repertoire of 10646 for identifiers you need no normalization. 

> at no charge.  Is the same true of ISO-10646?

the ISO 10646 case folding data is available from the web too.
It is included in the ISO 14651 standard.

Keld

---

From: John C Klensin <[email-masked]>
Date: Mon, 13 May 2002 07:37:49 -0400

--On Monday, 13 May, 2002 10:55 +0000 "Adam M. Costello"
<[email-masked]> wrote:

> normalization forms or case folding.  Therefore IDNA cannot
> avoid referencing Unicode.  Once we reference Unicode, there's
> no point in referencing ISO-10646, because it doesn't contain
> anything of interest that isn't already in Unicode.
> 
> Wouldn't it be ironic for the IETF to dismiss another
> standard-producing organization as not being official enough?
> Hasn't that same charge historically been made against the
> IETF itself?

Adam, for whatever it is worth, a distinction IETF has
traditionally made is between public-consensus, open-standards
bodies and consortia.  We've tried to be especially careful
about consortia that have high barriers to entry by interested
parties who are not large and well-funded corporations, since
such bodies are notoriously subject to capture by their member
companies.  We've also looked, at least implicitly, at the
stability of the materials we are contemplating referencing.
E.g., whether the organization, in practice, is committed enough
to stability to not change important elements of a referenced
document out from under us.

Note that the above paragraph doesn't say a thing about the
Unicode Consortium or UTC.  These are tradeoffs about which the
IESG and RFC Editor ultimately need to decide on a case by case
basis.   The same type of observation applies, I think, to your
position that, if we reference one UTC document, we might as
well reference Unicode documents exclusively and forget about
ISO 10646: Dan's preference, and probably mine (see below),
differ from yours, but it is important to see this as a
tradeoff, not a hard, fast, or obvious decision.

     john

p.s. If I were making the decisions around here, I'd reference
the code point set as "UCS" and then indicate, in the reference
text, a pointer to 10646 as authoritative and that the Unicode
spec contains the same set of code point mappings.  That is more
or less what the Unicode spec, as I read it, seems to say.  And
I'd say that as neutrally as possible.  But that is just my
personal taste in the matter.

---

From: "Mark Davis" <[email-masked]>
Date: Mon, 13 May 2002 07:05:49 -0700

There is no ISO Standard for case folding; ISO 14651 is for collation.
It doesn't provide a case folding; it maps characters to weights, not
to other characters.

You are wrong about normalization. Many languages require combining
marks for correct representation, and once you have more than one
combining mark you need a mechanism for determining the ordering.

For more about collation, case mapping, and normalization, I suggest
you read:

http://www.unicode.org/reports/tr10/
http://www.unicode.org/reports/tr21/
http://www.unicode.org/reports/tr15/

Mark

(P.S. I will be unable to reply to any answer to this message, since I
will be en route to Dublin.)
__________

http://www.macchiato.com

 "Eppur si muove"

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From: Keld Jørn Simonsen <[email-masked]>
Date: Mon, 13 May 2002 16:22:47 +0200

> It doesn't provide a case folding; it maps characters to weights, not

ISO 14651 can also be used for case folding, or for comparison of two
strings regardless of case.

Best regards
keld