On 02/08/2004 09:25, Antoine Leca wrote:
On Friday, July 30th, 2004 19:47, Peter Kirk va escriure: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.
<snip>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.
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)
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 [EMAIL PROTECTED] (personal) [EMAIL PROTECTED] (work) http://www.qaya.org/
