Protocol-08 (and status of Defs-04 and Rationale-06)

Erik van der Poel erikv at google.com
Tue Dec 9 16:40:21 CET 2008


All of the bidi rules, including rule 4, have been tested by Harald
and myself. Admittedly, Harald was the one who came up with the rules,
but I tested all of the rules, by removing one, running the program,
finding the problem, reinserting that rule, removing the next rule,
and so on. In other words, not one of the rules can be removed at this
point.

It might be possible to change the rules and find a different set of
rules where not one of them can be removed, but at this point in time,
I don't know whether it's worth it. (Unless someone can come up with
character sequences that are really needed or highly desirable that
fall afoul of the current rules.)

Erik

On Tue, Dec 9, 2008 at 7:20 AM, Eric Brunner-Williams
<ebw at abenaki.wabanaki.net> wrote:
> Thank you. Earlier I asked someone else about rule 4. The response was not
> so informative, could I trouble you to answer the rational question for that
> rule also?
>
> Eric
>
> Erik van der Poel wrote:
>>
>> Harald and I did exhaustive tests using two different implementations
>> of the bidi algorithm (he used his own, I used ICU for C/C++). We
>> found that without that rule, you'd get the kind of behavior that we
>> don't want. See Label Uniqueness and Character Grouping in:
>>
>> http://tools.ietf.org/html/draft-ietf-idnabis-bidi-03#section-3
>>
>> Erik
>>
>> On Tue, Dec 9, 2008 at 6:37 AM, Eric Brunner-Williams
>> <ebw at abenaki.wabanaki.net> wrote:
>>
>>>
>>> Harald Alvestrand wrote:
>>>
>>>>
>>>> Eric Brunner-Williams wrote:
>>>>
>>>>>>
>>>>>>          Alright, that is what has been proposed so far. *But* we
>>>>>> now need
>>>>>> to take into account Harald's reminder that some combinations
>>>>>> are already disallowed separately by the bidi rules on label
>>>>>> well-formedness, quite independently of any consideration of
>>>>>> CONTEXTO categorization. What the bidi rules require of label
>>>>>> formation is:
>>>>>>
>>>>>> Bidi:     Forbid (d) and (f) [and (g) by corollary]. Allow (e).
>>>>>>
>>>>>>
>>>>>
>>>>> Could you point out the lines in bidi you are referring to here?
>>>>>
>>>>>
>>>>>
>>>>
>>>> Section 2 rule 5:
>>>>
>>>>  5.  If an EN is present, no AN may be present, and vice versa.
>>>>
>>>>
>>>>                     Harald
>>>>
>>>
>>> Thank you. I thought that was the case. Now where is the rational for
>>> the rule?
>>>
>>> Eric
>>> _______________________________________________
>>> Idna-update mailing list
>>> Idna-update at alvestrand.no
>>> http://www.alvestrand.no/mailman/listinfo/idna-update
>>>
>>>
>>
>>
>>
>


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