local mappings

[Erik van der Poel]

On Fri, Jan 23, 2009 at 8:42 AM, Andrew Sullivan <ajs at shinkuro.com> wrote:
> The only suggestion I have for this is to tighten the rules more.  One
> way of tightening them is to do as Mark suggested, and say "mapping
> for IDNA2003:IDNA2008, and nothing else" (I think that's what he said;
> apologies if I put words in his mouth).  An alternative would be to
> put together a registry of known mappings, and say, "These are
> acceptable, and everything else MUST fail."  The icky thing about
> that, of course, is that it puts us back in the business of deciding
> "legal" characters, and that's supposed to be a policy decision.

Yes, it would be a good idea to tighten the recommendations for local
mappings. I think we should also add at least one example, and the
example I would choose is the Turkish dotted/dotless 'i' in upper and
lower case.

The recommendation I would suggest would go roughly along the
following lines. On the registration side, the implementation should
ask the user to confirm the domain name that was entered, after
lower-casing using the user's language's rules.

On the lookup side, if the user is typing characters one by one,
lower-casing should follow that user's language's rules. If the user
is providing the domain name in one fell swoop (e.g. copy-and-paste,
clicking on link), then the implementation should not apply the user's
language's rules, but should apply the global mapping (a la IDNA2003),
because the user has no way of knowing the intent of the original
author of the string containing the domain name.

But this is exactly where some members of the WG are likely to
disagree, because they are willing to allow local mappings but want to
get rid of the global mappings.

So we are back to square one, lack of consensus on the issue of global mappings.

Erik