comments on draft-ietf-idnabis-bidi

Vint Cerf vint at google.com
Tue Aug 4 12:23:02 CEST 2009


thanks erik that is most helpful.

any comments on the EN/CS interior question that Harald raised?

v

On Aug 3, 2009, at 8:25 PM, Erik van der Poel wrote:

> I have tested this new set of rules with domain names up to 9
> characters and they work for both the Label Uniqueness and Character
> Grouping requirements.
>
> Erik
>
> On Mon, Aug 3, 2009 at 4:34 AM, Harald Tveit
> Alvestrand<harald at alvestrand.no> wrote:
>> Matitiahu Allouche skrev:
>>> In my previous suggestions, I did not take in consideration that  
>>> the rules
>>> are meant to codify also labels which do not contain any RTL  
>>> characters.
>>> Having understood that, here is an updated version of my  
>>> suggestions:
>>>
>>> Definitions:
>>>
>>> 1. Bidi domain names are domain names which include at least one RTL
>>> label.
>>>
>>> 2. A RTL label is a label which contains at least one character of  
>>> type R
>>> or AL or AN.
>>>
>>> Rules for RTL labels in Bidi domain names:
>>>
>>>    1.  Only characters with the BIDI properties R, AL, AN, EN, ES,
>>>        CS, ET, ON, BN and NSM are allowed in RTL labels.
>>>
>>>    2.  The first position must be a character with Bidi property R  
>>> or AL.
>>>
>>>    3.  The last position must be a character with Bidi property R,  
>>> AL, EN
>>>        or AN, followed by zero or more NSM.
>>>
>>>    4.  If an EN is present, no AN may be present, and vice versa.
>>>
>>>
>>> Rules for non-RTL labels in Bidi domain names:
>>>
>>>    1.  Only characters with the BIDI properties L, EN, ES,
>>>        CS, ET, ON and NSM are allowed in non-RTL labels.
>>>
>>>    2.  The first position must be a character with Bidi property L.
>>>
>>>    3.  The last position must be a character with Bidi property L  
>>> or EN,
>>>        followed by zero or more NSM, or the two last positions  
>>> must be
>>>        EN followed by ET.
>>>
>>>
>>>
>> Thank you again - I have now implemented this algorithm and  
>> compared the
>> result for the "Character Grouping Requirement" up to a length of 3
>> characters (my perl code is chugging on longer strings as we speak).
>>
>> I hope Erik can take a look at the "Label Uniqueness Requirement",  
>> which
>> I don't have code to test for.
>>
>> The difference between the two algorithms seems to be that your  
>> proposal
>> allows CS and ET within a label, but not at the ends. Was this an
>> intentional difference?
>>
>>                  Harald
>>
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>> Idna-update at alvestrand.no
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>>
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