Mapping (was: Issues lists and the "preprocessing" topic)

Vint Cerf vint at google.com
Sat Aug 23 01:30:22 CEST 2008


If I can express a personal preference it would be to move towards  
(3) in as factual a way as possible. I would be hoping for something  
like:

IDNA2003 did things THIS way and they had the following implications.
IDNA2008 does things THAT way and the change is partly the result of  
experience (cite some??) and partly a result of WG deliberations and  
re-thinking in the light of experience.  the implications of the  
differences are: a), b) c)...

I don't know that it is possible to formulate the rationale document  
in such a way but it is the style that I am attempting to capture  
here, more than anything else.

vint




On Aug 22, 2008, at 6:18 PM, John C Klensin wrote:

>
>
> --On Wednesday, 20 August, 2008 09:55 -0700 Erik van der Poel
> <erikv at google.com> wrote:
>
>> The current IDNA spec is IDNA2003, and it includes the default
>> pre-processing steps. Now, IDNA200X is removing (the details
>> of) the pre-processing steps, so it ought to explain this
>> major difference between IDNA2003 and 200X. This explanation
>> can mention the difference between the "default"
>> pre-processing (as seen in IDNA2003 and HTML today) and the
>> per-locale UI pre-processing such as Turkish dotted/dotless
>> uppercase 'i'. If the WG consensus is to leave out any mention
>> of UI pre-processing, that is fine, but I think it is quite
>> important that IDNA200X explain that the default
>> pre-processing of IDNA2003 has been removed.
>
> I agree and you didn't even need to twist my arm.
>
> But I have a problem on which I need advice (and, ideally,
> specific text or instructions) from the WG.   It appears to me
> that there are three ways to address the differences between
> IDNA2003 and IDNA2008, of which this one and the exclusion of
> non-letter/ non-digit characters may be the ones with the
> largest impact.
>
> 	(1) We explain what IDNA2008 does and ignore IDNA2003
> 	and the differences entirely.
> 	
> 	(2) We explain what IDNA2008 does and note that it is
> 	different but don't explain why.
> 	
> 	(3) We explain the issues with mapping and why we
> 	decided to go from a "map whenever possible so as to
> 	include most Unicode characters somehow" logic to a
> 	"don't map so as to make behavior more understandable
> 	and U-labels and A-labels convertible to each other
> 	without information loss" logic.
>
> Rationale and its predecessors started with (3).  I was told to
> tear out the text that seemed critical of IDNA2003, with one key
> comment being that type of justification may have been important
> in getting where we are but that it is no longer important now
> that the WG is chartered, etc.   So we are now roughly at (2)
> with some of the WG membership still believing that we should be
> at (1), i.e., with all explanatory material discarded.
>
> I'm happy to go back toward (3) --especially since I've never
> been convinced that removing those explanations was wise-- but I
> have two problems.  I don't know how to say "this is different
> from IDNA2003 because..." without saying things about the
> IDNA2003 strategy that some will construe as critical and
> negative.  Others might be able to do better.   Or it is
> possible that what we really need to do is to strengthen (2)
> without making a "why this is different" comparison.   I've
> already done a bit of the latter and hope that I can finish up
> the pending drafts and get them posted this weekend (this last
> week or so have been terrors for reasons unrelated to IDNA).
> But I don't know if the new text will be adequate; if it is not,
> I would really appreciate specific suggestions.
>
> And, at some stage, I think we need Vint to see if he can state
> a formal consensus call on whether we want "why this is
> different" explanations even if those explanations could be
> interpreted as critical of IDNA2003.
>
>     john
>
>
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