Re: COMBINING DOUBLE INVERTED BREVE

From: Philippe Verdy (verdy_p@wanadoo.fr)
Date: Thu Apr 14 2005 - 16:38:15 CST

  • Next message: Michael Everson: "Re: [Unicode-Afr] joyeux anniversaire au n'ko. happy birthday to n'ko"

    From: <Lorna_Priest@sil.org>
    To: <unicode@unicode.org>
    Sent: Thursday, April 14, 2005 11:06 PM
    Subject: COMBINING DOUBLE INVERTED BREVE

    > Two questions about the double-width diacritics such as U+0361 COMBINING
    > DOUBLE INVERTED BREV:
    >
    > 1) What is the correct way to encode an acute accent (U+0301) *above* a
    > COMBINING DOUBLE INVERTED BREVE (U+0361)? See, for example,
    > http://scripts.sil.org/cms/sites/nrsi/media/AcuteOver0361.png

    Isn't this a *double* acute over a double inverted breve?

    > In particular, is this an appropriate use of the new (4.1) semantics of
    > CGJ (U+034F) between combining marks, e.g:
    >
    > U+0061 U+0361 U+034F U+0301 U+0065

    CGJ seems appropriate, because the double inverted breve U+0361 (liaison) is
    supposed to be encoded between the two sub-graphemes it links, and displayed
    above both of them. If you encode an acute U+0301, its combining class 230
    will be lower than the combining class of the double inverted breve (234),
    so without CGJ, the string:

        U+0061 U+0361 U+0301 U+0065

    would become canonically equivalent to its normalized form:

        U+0061 U+0301 U+0361 U+0065

    which can be recomposed in NFC form as:

        U+00E1 U+0361 U+0065

    and so it would mean an '', followed by 'e', and linked by the combining
    "double inverted breve" (what a bad name for what is really a linking mark!)
    above them.

    As you want to avoid that reordering where the accent is moved below the
    inverted breve, CGJ is there to block accents reordering in normalized
    forms, and to keep the expected semantic.

    The problem is that I am not sure that this is a normal acute accent. May be
    this is a double-wide acute accent (sorry for the name but there's also a
    "double acute" accent, where double means "repeated twice side-by-side")
    which may be encoded separately, with the combining class 234, and for which
    no CGJ would be needed (additionaly, it would be possible to put this accent
    above two letters without the double-wide inverted breve.



    This archive was generated by hypermail 2.1.5 : Thu Apr 14 2005 - 16:39:32 CST