I-D Action:draft-alvestrand-idna-bidi-04.txt (fwd)

Harald Tveit Alvestrand harald at alvestrand.no
Fri Feb 15 04:39:52 CET 2008



--On 14. februar 2008 14:02 -0800 Erik van der Poel <erikv at google.com> 
wrote:

> Harald, Patrik and John,
>
> Thanks for posting the new version of the IDNA200X bidi spec.
>
> I see that you have a recommendation for registries in the final
> paragraph of section 6.1. So a registry only needs to be concerned
> about the next level up from the label being registered, if that label
> contains any "right-to-left" characters. We may need to tighten that
> up to say R, AL or AN? Or just R and AL?

When I wrote it, I thought R, AL and AN.

> Also, what would the recommendation be for resolvers? I suppose they
> would have a similar rule for the next level up, but there is also the
> rule "ES and ON, followed by zero or more NSM, is not allowed in the
> last position", so a resolver may also need to look at the next level
> *down*, right?

Yes, it does. I think the defensive test (and the one that is simplest to 
code) for a resolver would be to flag anything where the whole domain name 
contains a R/AL/AN and where any label violates the bidi rule as "possibly 
confusing".

Is it OK to say that one should refuse to look up any such name?

> ES is European number separator (such as + and -) while ON is other
> neutral (such as @ and &), so maybe we could simplify the resolver's
> job by making ES and ON DISALLOWED in the Table spec (except for
> hyphen (-), which would be CONTEXTO).
>
> This way, a resolver can process labels in (logical) order, and would
> not have to backtrack to the previous label if the current label
> contains any R/AL/AN.

Back to the discussion about special treatment of the hyphen.... it would 
make the overall spec more orthogonal if the hyphen and the middle dot 
(which is an ON) was CONTEXTO and listed as exceptions, while the general 
class they belong to is DISALLOWED (middle dot already is).

But currently, the tables document doesn't touch the bidi properties at all 
- so putting ES and ON into DISALOWED would be introducing a new class of 
criteria into the document. Do we need to do that?

             Harald, in Delhi



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