On 11/3/97 1:04 AM, Martin J. Dürst (mduerst@ifi.unizh.ch) wrote:
>On Sun, 2 Nov 1997, Michael Everson wrote:
>
>> The proposal gives Etruscan inherent right-to-left directionality and says
>> that directionality overrides can be used to reverse this.
>>
>> I don't remember a discussion resolving this. Is this what we want? Or do
>> we want the reverse? John Jenkins' proposals have shown the code table with
>> R-L glyphs; mine have shown the code table with L-R glyphs.
>>
>> http://www.indigo.ie/egt/standards/iso10646/plane-1/eo.html
>> http://www.unicode.org/pending/etruscan/Etruscan.html
>
>I think you don't want to use overriding to reverse things. What you
>want is a mechanism at a higher level (e.g. styles). Setting a text
>in left-to-right direction that runs over several lines with overrides
>is not absolutely impossible, but extremely tedious; every character
>has to be enclosed in an LRO-PDF pair.
Huh? You lost me here.
>So for the directionality,
>it will be so that the inherent directionality can be used in plain
>text, the other one probably shouln't be used in plain text, but
>only formatted. Bustrophedon can only be achieved with styles, not
>with BIDI controls.
>
Or with hard line breaks.
Of course, I don't hear anybody asserting that Unicode *ought* to support boustrophedon in plain text, anyway.
>I'll be at the W3C HTML/CSS WG meetings, and have a close look at
>these things.
>
>For Etruscan as well as Hieroglyphs,..., the situation is almost the
>same. RTL is more frequent in the ancient texts, LTR seems more
>popular for mixed scholarly texts. It would be very nice if:
>
>- This and similar cases could be solved in the same way
No problem here.
>- The fact that BIDI implementations will have difficulties to be
> updated with new character properties when new characters
> are added (this would in essence be a strong suggestion that
> everything except U+0580-U+7FF is LTR) would get consideration
>
Er, I don't think we can do that. I don't think implementers should count on all RTL scripts being encoded in that one range. Certainly we anticipate various dead RTL scripts being put on Plane 1 (Meroitic, South Arabian).
People should be getting the directionality properties from the properties file, nowhere else.
=====
John H. Jenkins
jenkins@apple.com
tseng@blueneptune.com
http://www.blueneptune.com/~tseng
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