AW: AW: sharp s (Eszett)

Harald Tveit Alvestrand harald at
Tue Mar 11 15:20:39 CET 2008

--On Tuesday, March 11, 2008 11:29:30 +0100 Georg Ochsner 
<g.ochsner at> wrote:

>> -----Ursprüngliche Nachricht-----
>> Von: Kenneth Whistler
>> Gesendet: Montag, 10. März 2008 21:55
>> Jelte Jansen said:
>> > So if IDNAbis would make an exception for the sharp S, and allow it as
>> > a separate symbol, would there be people running to their lawyers
>> > because they think it's equivalent to ss too ...
>> It *is* equivalent to ss, too. It just depends on what level
>> and type of equivalence you are talking about. They aren't
>> equivalent for spelling, obviously -- but they *are* equivalent
>> for some types of searching and sorting.
> Why should they be equivalent in general just because there are
> equivalences for "some types of searching and sorting"?

Note: We're not talking about "equivalent in general" here, we're talking 
about "permitted as a lookup key in the DNS".

Under IDNA2003, we were talking about "if the user gives us ß, we will 
look up ss". Under IDNA200x, we're only talking about "can ß be used to 
lookup information in the DNS?", since mapping user expectations to lookup 
keys is considered to be outside the protocol.

We have four alternatives:

1 - No, it can't
2 - Yes, it can, because we're adding a special case
3 - Yes, it can, and because of this example, we'll throw away the 
requirement that a character be stable under full casefolding in order to 
be used as lookup
4 - Yes, it can, and the Unicode tables should be changed to make it stable 
under casefolding.

1 is what's currently proposed, 2 and 3 can be accomplished by changes to 
the idnabis documents (noting that 3 can have unforeseen effects on other 
characters), 4 requires changes to Unicode.

Note that if you're arguing the 4th case, that belongs on the 
unicode at unicode list, not here.


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