I-D Action:draft-ietf-idnabis-mappings-00.txt

John C Klensin klensin at jck.com
Sun Jun 7 01:02:24 CEST 2009

--On Friday, June 05, 2009 14:57 -0500 Pete Resnick
<presnick at qualcomm.com> wrote:

> On 5/30/09 at 11:19 AM -0700, Paul Hoffman wrote:
>> I propose to change the list in section 3 to:
>>    1.  U+00DF, U+03C2, and U+200C are mapped to characters
>>    that (a) are not used in the input, (b) are unaffected by
>>        any NFKC mapping, and (c) do not affect other
>>        characters in an NFKC mapping.
>>    2.  Capital (upper case) characters are mapped to their
>>    small (lower case) equivalents. [[anchor2: Need reference
>>        to "toLowerCase"]]
>>    3.  All characters are mapped using Unicode Normalization
>>    Form KC (NFKC).  [Unicode51]
> So are folks really OK with me changing the draft to do this 
> map-and-remap thing with  U+00DF, U+03C2, and U+200C and then
> use  NFKC? There has not been significant enough discussion
> for me to  determine what the group wants.

I continue to believe that use of NKFC without exclusion of
character groups for which there are no justifications is

(i) A violation of the "inclusion" model of IDNA2008

(ii) A violation of the closely-related protocol design
principle that one should include only those things for which
one has both use and understanding because it is easier to add
later than it is to remove.

(iii) An increased risk, however slight, that we will, in the
future, get strong demands from some particular community to
treat a character classified by Unicode as "compatibility" as a
real and distinct character.  If such a character is disallowed
by virtue of not being mapped, we will have the difficult
problem of changing a disallowed character to a PVALID one.
But, if it is mapped to something else, we will have to revisit
the very complex discussions that we have had over Eszett and
Final Sigma.  We should not incur that risk unless there is a
reason to do so.

I note that I don't believe there has been any substantive
responses to my earlier note that outlined the above objections
since I posted it.


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