Re: How to get a Bidi Override with PUAs?

From: Philippe Verdy (verdy_p@wanadoo.fr)
Date: Thu Mar 25 2004 - 05:34:16 EST

  • Next message: Philippe Verdy: "Re: How to get a Bidi Override with PUAs?"

    From: "Kenneth Whistler" <kenw@sybase.com>
    > Philippe Verdy asked:
    > > What is, in Unicode the BiDi behavior of PUAs?
    > They default to bd=L. From DerivedBidiClass-4.0.1.txt:
    >
    > E000..F8FF ; L # Co [6400] <private-use-E000>..<private-use-F8FF>

    Sorry about that, I did a bug when trying various ways to override BiDi behavior
    of my PUAs, and I just saw that my test documents where encoding the RLO after
    the PUAs (I had to hexdump my test file to see what was happening). Encoding it
    before the PUAs effectively works in IE and NotePad on Windows (but the <bdo
    dir="rtl"> method does not work, as it just modifies the paragraph alignment
    style and does not force the BiDi behavior of characters that are not
    Bidi-neutral).

    My opinion is that bd=L was a bad choice for PUAs that should have better used a
    bd=ON property, like for standard generic punctuation marks which are already
    neutral in general. I really don't understand the rationale for a _strong_ LTR
    directionality for PUAs, and why we can't even use a RLM to override only one
    PUA within a otherwise RTL text; having to use RLO implies lots of caveats when
    editing a text document where there are also portions with Latin letters, as it
    completely disables the normal automatic Bidi rendering.



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