Consensus Call Tranche 8 (Character Adjustments)

[John C Klensin]

--On Thursday, 16 October, 2008 10:44 +0900 Martin Duerst
<duerst at it.aoyama.ac.jp> wrote:

> 
> Characterizing the eszett as an exception is correct on one
> level, but in my view, it's only an exception because we took
> the wrong rules for IDNA2003. And these rules are even more
> wrong for IDNA 2008.
> 
> What IDNA 2003 needed was some kind of case mapping. Unicode
> provided two levels of case mapping: a) the simple one-to-one
> case mappings, and b) special-casing for cases such as eszett
> (on top of a).
> 
> At the time of IDNA 2003, the mood was: 1) We have to take some
> existing tables, we can't construct our own or we'll never
> finish. 2) Take special-casing, because that's what you would
> do for search, and domain name lookup is essentially search.
> 
> The problem with this is that 2) isn't exactly true. In search,
> you get back original documents, so there are no misspelling
> issues. For IDNs, you get back whatever you put in after case
> folding, and so you end up with misspellings.
> 
> So in my view, we should look at what we get when we remove
> special-casing from our rules.

FWIW, we are in complete agreement on this reasoning and
conclusion and it is consistent with the logic I've personally
been trying to apply to character classification.

    john