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closed issue [bidiDigits-18] (was: Re: Bidi: now I'm confused)

From: Martin Duerst <duerst@w3.org>
Date: Sun, 21 Mar 2004 11:41:30 -0500
Message-Id: <>
To: Roy Badami <roy@gnomon.org.uk>, ietf-imaa@imc.org
Cc: public-iri@w3.org, bidi@unicode.org

Hello Roy, others,

As proposed, I have added an additional example (example 10) in
(and also in http://www.w3.org/International/iri-edit/BidiExamples).

I'm herewith closing this issue
Please tell me if you think that's not enough
(and in that case, if possible, what else is needed).

Regards,   Martin.

At 15:50 03/09/08 -0400, Martin Duerst wrote:

>Hello Roy,
>I think that in general, you are right about your analysis.
>Having labels (or other components) with numbers only may
>lead to ambiguous displays. I seem to remember that we were
>actually aware of that fact, but there was not much to do
>about it:
>- There currently are labels with only digits in the DNS,
>   outlawing them is not an option. (it would have been nice
>   if we could have said that the same restrictions apply
>   for digits and LTR letters as they do for digits and RTL
>   letters)
>- Very explicitly for IDN, but also in many ways for IRIs,
>   it is highly undesirable to have inforced restrictions
>   on two or more labels/components. (note that this may be
>   somewhat different for the LHS side)
>I have created an issue for this for the IRI draft, at
>I propose to address this by adding text that points out
>such cases and warns against them (without going as far as
>actually prohibiting them). I hope that this is acceptable
>for you.
>By the way, the alternative of having components displayed
>strictly LTR was what we had for a long time. The two problems
>with this approach are:
>- It does not seem to correspond with what Arabic and Hebrew
>   writers do naturally, in particular for freestanding domain
>   names.
>- It would require much more control over the contexts of
>   IRI display than we think will be available (if we get
>   an overall context of LTR reasonably widely implemented,
>   I think we already have achieved something).
>Regards,    Martin.
>At 15:08 03/09/07 +0100, Roy Badami wrote:
>>Ok, I have a problem with what I understand to be the display model
>>for IDNA and IRI (and presumably by extension IMA).
>>I'm assuming that the display model is 'render using bidi in an LTR
>>Specifically, the IRI draft says:
>>   When rendered, bidirectional IRIs MUST be rendered using the Unicode
>>   Bidirectional Algorithm [UNIV4], [UNI9]. Bidirectional IRIs MUST be
>>   rendered with an overall left-to-right (ltr) direction.
>>The latter requirement isn't specified in bidi-speak, but is
>>presumably to be interpreted as saying they must be rendered at an
>>even embedding level.  Actually, this isn't quite enough in the
>>general case, since what comes before the string may affect weak type
>>resolution, but since IRIs generally start with a latin letter
>>(generally 'h' :) this isn't really much of a problem.
>>So lets for the moment assume that the display model is that IDNs,
>>IRIs, IMAs are rendered at an even embedding level, such that the
>>IDN/IRI/IMA constitutes the sole text in the level run.  (This can
>>easily be achieved by bracketing the string with LRE and PDF prior to
>>Consider the domain:
>>123.ARAB.com (logical order)
>>123.BARA.com (display order)
>>now consider the domain:
>>ARAB.123.com (logical order)
>>123.BARA.com (display order)
>>Ergo, we need another display model; this one doesn't work, at least
>>not if we don't want two completely different domains to display
>>I recall that there was a proposal on the IDN list that domains should
>>always be rendered with the labels appearing in order, least
>>significant to the left and top-level domain on the right.  (This can
>>be trivially achieved by bracketing each label with LRE/PDF,
>>separating the labels with dots, and then bracketing the whole domain
>>with LRE/PDF.)
>>This would solve the above problem, but potentially might be less
>>friendly to users of RTL languages in other ways.
>>It also clearly is not what the authors of stringprep had in mind,
>>since the bidi restrictions in stringprep are much stronger than would
>>be necessary if this was the model.
>>         -roy
Received on Sunday, 21 March 2004 11:44:12 UTC

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