Re: letters with palatal hook

Date: Wed Apr 02 2003 - 02:45:35 EST

  • Next message: Janusz S. Bień: "Re: ogonek vs. retroflex hook"

    John Hudson <> wrote on 04/02/2003 12:27:08 AM:

    > I can't see any advantage to such atomic encoding in a modern text
    > processing environment with smart font support. It is easy enough to map
    > e.g. b + palatal hook to a ligature using a glyph composition feature.

    In a unicoRe thread last fall,

    Ken Whistler wrote on 2002-10-15:

    Just another example of the line that had to be drawn for
    decompositions. Diacritics involving baseform shape alterations --
    with the exception of cedillas and ogoneks, which were treated
    as honorary non-spacing marks below -- were excluded from the
    original set of decompositions published in Unicode 1.1 in 1993,
    and later corrected and rationalized in Unicode 2.0, with data
    tables distributed...

    As far as I know, the same completeness issue does not apply for the
    retroflex and palatal hooks -- so for those, use of the preformed
    base letters is probably the better recommendation, rather than use
    of the non-spacing diacritics together with ligature tables in the fonts.


    Michael Everson wrote on 2002-10-16:

    All of these things should be encoded as things-without-diacritics,
    as unitary characters.

    Also, earlier in 2002 in offline discussion Ken wrote,

    > I'm also not sure
    > how/when 0321 should be used.

    Sparingly, I think. It is one of the very small set of actually
    attaching diacritics for IPA. As such, it isn't going to work for
    rendering on most systems unless you have proper fonts that have
    ligature tables to fully-formed glyphs for the combinations.

    It is feasible to use it, of course, but generally, the letters with
    retroflex or palatal hooks have been separately encoded, anyway.
    Cf. U+01AB, not given a decomposition.


    My suggestion is just to bring in a proposal [for palatal-hook characters.]
    And name them all consistently
    as ...WITH PALATAL HOOK, to be consistent with U+01AB...

    Given the fact that a precomposed palatal hook precedent exists, and that
    all the retroflex hook forms also got encoded -- all with no
    explicit decompositions, this way seems most consistent.

    In my opinion, neither the retroflex nor palatal hook are
    useful as combining marks per se, since they are really
    baseform modification diacritics (like the descender for
    Cyrillic), and so cannot be used by a renderer for generic
    application by rule.

    Their usefulness is rather to have a character to indicate
    the diacritic per se (as for metadiscussions about IPA
    orthography), and as placeholders for such things as the
    Unicode Collation Algorithm, which can use them to do the
    secondary weighting for characters with those diacritics,
    if one chooses.

    I was just following the prevailing wisdom. I think the strongest point in
    this in the fact that generic application by rule is not possible, unlike
    diacritics like acute that can be handled by generic mechanisms.

    BTW, Ken, not too long ago we talked about overlaid-tilde typeforms, and
    you wanted to use the combining overlay in that case, but it seems to me
    that the same argument of inability to have generic application by rule
    applies in those cases. But I don't yet have what I'd consider good enough
    evidence for proposing a set of tilde-overlaid forms.

    - Peter

    Peter Constable

    Non-Roman Script Initiative, SIL International
    7500 W. Camp Wisdom Rd., Dallas, TX 75236, USA
    Tel: +1 972 708 7485

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