Re: Need for Level Direction Mark

From: Kent Karlsson <>
Date: Wed, 14 Sep 2011 13:28:46 +0200

Den 2011-09-14 03:31, skrev "Philippe Verdy" <>:

> 2011/9/13 Kent Karlsson <>:
>> for the new one, and to the paragraph bidi level for the three old ones). (I
>> know, this would be a form of "option 1" in the PRI.)
> You can turn it as you want it is still a splitting of the bidi class
> if you change the behavior of class S like this.

I did write that it was a version of the PRIs "option 1"!

> Onve again, if you
> want to encode new characters, why would you restrict yourself to
> reusing an existing bidi class just to break it?

Because that stability guarantee says "The Bidi_Class property values will
not be further subdivided." I'm not too keen on the word "subdivided" here,
but it (here) means there will be *no additions* to the set of values for
the Bidi_class property. Not even for new characters.

As far as I can tell, there is no restriction saying that the bidi algorithm
cannot look at code points as well as bidi category values.

But as I pointed out in my submitted response to the PRI, the bidi algorithm
has "glaring deficiencies" that I think would be best handled by going for
the third option: "bidi v. 2", where these "glaring deficiencies" can be
addressed; to a large extent by the use of *implicit* LDMs (and *implicit*
LRE/RLEs and PDFs).

    /Kent K
Received on Wed Sep 14 2011 - 06:32:48 CDT

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