Subject: Re: [idn] Re: character tables

From: John C Klensin <[email-masked]>
Date: Mon, 28 Feb 2005 21:12:02 -0500

--On Sunday, 27 February, 2005 20:19 -0800 Erik van der Poel
<[email-masked]> wrote:

> John C Klensin wrote:
>> 
>> 	(i) ICANN is still assuming that this is a registry
>> 	issue.  As such, if someone else starts guessing at what
>> 	a registry is doing, we may get into trouble, especially
>> 	since the tables may not show all of the relevant
>> 	registry rules and restrictions.
> 
> Hmmm... GNU libidn already seems to be trying to use
> machine-readable tables. I had a look at the GNU libidn page:
> 
> http://www.gnu.org/software/libidn/
> 
> It has a copy of an expired Internet Draft by Paul Hoffman:
> 
> http://josefsson.org/cgi-bin/rfcmarkup?url=http://josefsson.or
> g/cgi-bin/viewcvs.cgi/*checkout*/libidn/doc/specifications/dra
> ft-hoffman-idn-reg-02.txt
> 
> This draft seems to be talking about bundling and blocking,
> which your draft talks about too. What happened here? Did Paul
> decide to let his expire?

Yes.  Paul more or less gave up (he can explain that decision; I
won't try to do it for him), then generously consented to the
inclusion of some of his text and definitions, and even more of
his concepts, into my draft.  A different way of looking at this
is that we found our drafts converging and I got the short straw
for producing a consolidated version and trying to walk it
through the works.   Paul gets considerable credit but bears no
responsibility or blame, for the result, but I hope we still are
in at least broad agreement.

> Anyway, my only reason for trying to get machine-readable
> tables was to figure out which Unicode character categories
> were being used. Another way to get this info is to simply ask
> the registries. Or, we can suggest a list of categories and
> see if they would be happy with a nameprep-bis that limits the
> characters to those categories.

As has been pointed out in other contexts, this is probably a
fool's errand.  If a registry declines to register something,
then is isn't present and there isn't much value in guessing
whether a lookup fails because the name was not registered or
because its registration was prohibited.   Conversely, if a
registry either has no rules or declines to follow the rules it
does have, knowing what those rules were supposed to be is not
terribly useful.

If a browser wants to apply sanity checks before it attempts a
DNS lookup, that is really a separate set of issues and
constraints.  And, again, knowing the rules a registry would
have applied if its authority reached down more than a level or
two probably isn't a big help.

   john