From: Peter Kirk (peterkirk@qaya.org)
Date: Mon Aug 02 2004 - 05:51:28 CDT
On 02/08/2004 09:25, Antoine Leca wrote:
>On Friday, July 30th, 2004 19:47, Peter Kirk va escriure:
>
>
>>>>There appear to be two errors (not listed in the errata page
>>>>http://www.unicode.org/errata/) in Figure 15.2 on page 391 of The
>>>>Unicode Standard 4.0, the online version at
>>>>http://www.unicode.org/versions/Unicode4.0.0/ch15.pdf.
>>>>
>>>>
><snip>
>
>
>>>>The fourth column is supposed to indicate the desired rendering of
>>>><C1, ZWJ, C2>. But in the text just before, ZWJ is specified as
>>>>
>>>>
>
>Otto answered:
>
>
>>>Read the paragraph immediately below that figure.
>>>
>>>
>>OK. I did. But I shouldn't have to do that as this figure is supposed
>>to be an example of what has been specified before.
>>
>>
>
>Then have a look at Unicode 3.0.1
><URL:http://www.unicode.org/reports/tr27/index.html#layout> and you will
>understand what did happen: there was initially the way you expected; but
>then (I cannot spot exactly when, but it should be possible to find this),
>for backward consideration, this very behaviour (requesting ligatures) was
>defeated for Arabic only. As a result, the table was updated, and now is
>about useless. We really should provide examples from others scripts (Khmer
>perhaps; and Sinhala, which appears to behave exactly this way according to
>SLS 1134, the Ceylanese standard)
>
>
>
Thank you for the explanation. I agree that the figure does not
illustrate what it claims to illustrate, and so seems to be incorrect
until you read the text which follows.
>
>
>>And there is still a problem with the text before the figure.
>>
>>
>
>Which text?
>
>
As I wrote before,
> There also seems to be an error in the text just before the figure
> which states "In the Arabic examples, the characters on the left side
> are in visual order already, but have not yet been shaped." In fact
> they have been shaped, at least in the second and third rows - no
> shaping applies (by default) to the fourth row.
>I was noticing a problem, but it is not what you are pointing out. ...
>
>
I agree that this looks like yet another problem.
I am looking at this in order to answer an argument that the new
proposal which I and a group of others have submitted on Hebrew Holam
(L2/04-307, http://www.qaya.org/academic/hebrew/Holam3.pdf) does not
conform to the TUS defined use of ZWNJ. Well, it seems that this whole
section of TUS is such a mess that it is hard to determine what use
actually is defined. It doesn't help that there is a difference of
opinion on the definition of "ligature": is a ligature as referred to in
this section a conceptual and graphical entity (as apparently in the TUS
glossary definition), or is it a technical means of implementing
rendering of certain character sequences within complex script rendering
technology? Another argument against our proposal is that by defining
ZWNJ as breaking a ligature I am specifying implementation. But that is
based on a confusion of the senses of "ligature". The proposal refers
primarily to ligatures as conceptual and graphical entities (although
its terminology may not be 100% clear). How these are implemented in
rendering engines is a matter for implementers, not for the standard.
-- Peter Kirk peter@qaya.org (personal) peterkirk@qaya.org (work) http://www.qaya.org/
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