Re: [idn] 1st stringprep issue: not answered and ignored

[Paul Hoffman / IMC <phoffman@imc.org>]

At 3:15 AM +0900 5/5/02, Soobok Lee wrote:
>----- Original Message -----
>From: "Paul Hoffman / IMC" <phoffman@imc.org>
>To: <idn@ops.ietf.org>
>Sent: Sunday, May 05, 2002 1:03 AM
>Subject: Re: [idn] 1st stringprep issue: not answered and ignored
>
>
>>  At 12:59 PM +0900 5/4/02, Soobok Lee wrote:
>>  >Stringprep should have contained warnings about this or included new
>>  >revised casefolding operatins/tables,
>>  >but it didn't .
>>
>>  Correct. This has been covered many times on the mailing list. You
>>  want stringprep to change the tables issued by the Unicode Consortium
>>  so that stringprep does not do NFKC the same way all other software
>>  that does NFKC does. There is little support for that proposition in
>>  the WG.
>
>I am not against NFKC.  I am not proposing for modification to NFKC,
>but to UAX21 casefoldings.

My apology for mixing up your previous arguments for changing NFKC 
with your current argument for changing UAX21. The result is, of 
course, the same: you are asking us to change an external standard so 
that our protocol will not work the same as other software that 
follows UAX21.

>  I just pointed our that The UAX21 casefolding is
>wrong at the example.

That's not true: you did much more than "just" point that out. You 
asked for us to change the mapping from the Unicode Consortium, and 
you accused the authors of the drafts of ignoring you.

>Who had answered at my questions before your this article?

You brought it up on the list in February; only one person supported 
your request, and he suggested that you take this to the Unicode 
Consortium.

There are numerous threads on this mailing list about why we should 
use the Unicode Consortium tables, even if we we think there are some 
problems with them.

>How to measure the consensus? I have never seen this WG had 
>discussed this issue in depth.

Have you participated in any other IETF Working Groups? If so, how 
did they measure consensus? If not, do you think it is appropriate 
for every working group to spend time discussing this? If you have 
not done so already, you should probably read 
<http://www.ietf.org/tao.html> and the other documents describing how 
the IETF works.

>The NFC(x) above is , for example, from IRI preprocessing or HTML authoring,
>which often require NFC normalization on their inputs.
>To rephrase the above equation,
>
>"NFKC(UAX21_casefold(NFC(x))) ==  NFKC(UAX21_casefold(x)) is not guaranteed."

Quite true. I think the following simpler statement is also true:
   "UAX21_casefold(NFC(x))) ==  UAX21_casefold(x)) is not guaranteed."

>If you preprocess IDN with NFC, you will get different namepreped ACE labels
>than before in the IDN samples including <I><dot-above>.

True, but irrelevant. Nameprep is called from IDNA. IDNA does not 
say, and has never said, "you can do NFC before processing the name". 
The fact that you might have done some processing on a name *before 
you processed IDNA*, and that pre-processing may cause you some 
surprises, is not an IDNA problem.

--Paul Hoffman, Director
--Internet Mail Consortium