Re: Printing and Displaying Dependent Vowels

From: Antoine Leca (
Date: Mon Mar 29 2004 - 08:09:47 EST

  • Next message: Peter Constable: "RE: Printing and Displaying Dependent Vowels"

    On Monday, March 29, 2004 2:14 PM, John Cowan va escriure:
    > The bottom line is that SP+vowel and NBSP+vowel are prescribed by the
    > Unicode Standard,

    I am sorry John, I should have miss a post of yours. I asked you where it is
    written, and did not find any answer to this; unless someone consider that
    all marks, including spacing combining vowels, are "(European) diacritics".

    I did find some things in UAX29 about grapheme clusters (as indicated by
    Philippe), but also found that Mc characters do not seem to be concerned
    (Mn, on the other hand, seems to are). I now understand that any base
    followed by a "Grapheme_Extend" are to be seen as a cluster. I found
    "Grapheme_Extend" as being defined as Other_Grapheme_Extend + Me + Mn in the
    UCD. (But was not able to encounter this in the standard itself. Never mind,
    I should have miss something obvious.)

    I am sorry to insist on these issues. I have really big problems to
    understand where are the specifications, when chapter 2.10 inside the
    Unicode book says one thing while dealing directly with the issue, while
    another document that is supposed to be as standard as well, says otherwise,
    or better is to be interpreted otherwise, and still none of them match
    exactly with what people are expecting in this forum.

    (And furthermore when asked about issues of conformance, the former answer
    was, "it does not matter", or "it should not matter", or "depending on what
    you are doing", etc., in a word ways to avoid answering the original

    > if they don't work [...] the system is broken.

    As James eloquently showed earlier today, I am not that sure we want things
    this way.

    The text in The Unicode Standard explicitely refers to the case of the
    European diacritics. There (well, here!), because of typing habits (use of
    so-called dead keys), users expects that combination of a diacritics and a
    space is rendered as a spacing clone of the diacritic. I read the 2.10
    snippet as guarding this convention.
    (Of course, this is my interpretation, I can very easily be wrong.)

    On the other hand, typing habits in other parts of the world are not that
    entrenched. After all, dead keys are with us for more than a century, while
    keyboard for combining characters that may reorder before the preceding
    characters are only twenty years old. Furthermore, custom is to provide
    disambiguating ways, such a bell (Thai) or a dotted circle, when a vowel is
    mistyped. Evidently, Microsoft did follow this when they designed
    Uniscribe/Indic OpenType. What you are saying is that when a mistyped vowel
    follow a space character, it should appear hanging from nothing, while
    situation will be different is typed after virama, or another vowel, or some
    other mark.

    As I said, I am not sure this is what we really want.


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