Re: How to get a Bidi Override with PUAs?

From: Philippe Verdy (
Date: Thu Mar 25 2004 - 05:01:31 EST

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

    From: "Mark Davis" <>

    > PUA characters can have any properties overridden, so it is perfectly
    > to have them all behave as R, or L, or any other BIDI class.
    > However, the RLO, LRO, or their HTML equivalents should work to override the
    > ordering.

    Exactly. And shamely this does not work properly as neither RLO or the HTML <bdo
    dir=rtl"> is working there.

    I did not complain about the fact that PUAs have a default LTR direction, what I
    want is just a way to override it effectively.
    In fact it's just a shame that we don't have separate blocks of PUAs with
    distinct direction properties (and it's probably too late to split these

    PUAs are still needed to allow creating conforming documents with scripts still
    not in Unicode (to be rendered with custom but still conforming fonts).

    Should I request such presentation feature to the CSS working group, so that a
    stylesheet can add custom character properties, notably for PUAs that are
    notoriously missing this feature, and where it's impossible to modify the core
    character properties coded in browsers and renderers?

    For now there's absolutely no mechanism to specify a set of custom character
    properties and this greatly limits the usage of PUAs to LTR scripts and symbol
    sets, and this segregation of RTL scripts is quite strange.

    What I did for now was to encode a document using the codepoints assigned
    normally to other RTL scripts, but this completely breaks the "character
    identity" requirement for Unicode conformance. May be others are doing the same
    (because it's a common old practice used in proposals for new LTR characters,
    where a custom font is used that remaps, most often, characters in the Latin-1

    I'm not satistifed have having to use these non-conforming solutions, when PUAs
    should be used for this purpose, even for RTL characters.

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