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

From: Roy Badami <roy@gnomon.org.uk>
Date: Mon, 8 Sep 2003 21:53:59 +0100
Message-ID: <16220.60519.876961.860988@moriarty.gnomon.org.uk>
To: Martin Duerst <duerst@w3.org>
Cc: Roy Badami <roy@gnomon.org.uk>, ietf-imaa@imc.org, public-iri@w3.org

 > 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:

More specifically, assuming labels (or syntactic components) obey the
stringprep bidi rules (as IDNA requires, and IRI has as a 'SHOULD')
then I think the problematic case is when a label contains one or more
digits, and no strong characters.  These are just quick examples off
the top of my head; I haven't checked them carefully against the bidi
algorithm.

	1-2.HEBREW.com (logical order)
	1-2.WERBEH.com (display order)

	HEBREW.1-2.com (logical order)
	1-2.WERBEH.com (display order)

And another.  N is a neutral character (presumably non-ASCII, since
there are no ASCII neutrals allowed by hostname rules).

	1N2.ABC.com (logical order)
	1N2.CBA.com (display order)

	ABC.2N1.com (logical order)
	1N2.CBA.com (display order)


Of course, this may need to be restated somewhat for IMA because the
LHS doesn't formally have structure.

 > 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.

If we can't change the display model (and I see why that may not be
desirable and/or practiable) then I guess that's all that can
realistically be done.  I'm tempted to say it ought to be a 'SHOULD
NOT', and not just a recommendation (in line with the other 'SHOULD
NOTs' about bidi IRIs).

I think that IMA will need to contain a similar 'SHOULD NOT'.

In the case of IMA we need to warn people (at least) against addresses
such as:

	123@ABC.com (logical order)
	ABC@123.com (logical order)

both of which display as 

	123@CBA.com (display order)

but I think there are other cases as well.

	-roy
Received on Monday, 8 September 2003 16:54:15 GMT

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