Consensus Call on Latin Sharp S and Greek Final Sigma

Vint Cerf vint at google.com
Tue Dec 1 05:19:45 CET 2009


We had long since concluded that there should be no mappings within  
protocol, either within the lookup procedure or the registration  
procedure.

We agreed to preserve the equivalence of A-label and U-label forms via  
punycode transformation/encoding.

We added a non-normative document about mapping for User Interface  
purposes. Implicit in that was awareness that context might make a  
difference as to choice of mapping.

Re-introduction of mandatory/normative mapping strikes me as old  
territory that had been settled.

Vint


On Nov 30, 2009, at 9:02 PM, Shawn Steele wrote:

> On 2009/11/30 16:45, Shawn Steele wrote:
>>> I agree with Mark that this is very badly worded.
>
>> Can you propose (in your eyes) better wording?
>
> It's easier to say it is badly worded :)  I'll try:
>
> (1) Both characters should be PVALID, the 2003 mappings will break.
> (2) The 2003 mappings MUST be applied to both characters, and both  
> characters should be DISALLOWED.
> (3) The 2003 mapping for Greek Small Letter Final Sigma MUST be  
> applied, but not the Latin Small Letter Sharp S mapping.  The Latin  
> Small Letter Sharp S should be PVALID.
> (4) The 2003 mappings for Latin Small Letter Sharp S MUST be  
> applied, but not the Greek Small Letter Final Sigma mapping.  The  
> Greek Small Letter Final Sigma should be PVALID.
>
> There's a fundamental problem with my wording; it presumes we have  
> to have mappings, which opens a different set of problems.  Perhaps  
> we should start with a consensus call on mappings first:
>
> (A) No mappings are permitted.
> (B) Only ASCII case mappings are permitted.
> (C) Any mapping MAY be used.
> (D) Only IDNA standard mappings MAY be used, other mappings are  
> disallowed.
> (E) IDNA standard mappings SHOULD be used, other mappings are  
> disallowed.
> (F) IDNA standard mappings MUST be used, other mappings are  
> disallowed.
>
> That leaves open what an "IDNA standard mapping" is, however I would  
> suggest that it be as close to IDNA2003 as possible, eg: UTR46.   
> Presumably if we knew mappings MUST NOT, MAY, SHOULD, or MUST be  
> used, then we could better agree on what exactly those mappings  
> should be.
>
> As everyone knows already, I would prefer (F) or (E), or reluctantly  
> (D).  IMO (A) is not practical, (B) is not internationalized, & (C)  
> is chaos.
>
> -Shawn



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