Re: conditional case mappings

From: Mark Davis (mark.davis@jtcsv.com)
Date: Thu Apr 29 2004 - 10:53:47 EDT

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    comments below.

    Mark
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    ----- Original Message -----
    From: "Theo Veenker" <Theo.Veenker@let.uu.nl>
    To: "unicode" <unicode@unicode.org>
    Sent: Thu, 2004 Apr 29 00:02
    Subject: conditional case mappings

    > I have two questions about the special case mappings.

    for others: http://www.unicode.org/Public/4.0-Update1/SpecialCasing-4.0.1.txt

    >
    > Some conditional case mappings map to a zero length code point string.
    > Is it valid to assume this will never happen for non-conditional mappings?

    I can't imagine a case like that.

    >
    > What are the values for the Special_Case_Condition; is is the contexts,
    > or the contexts plus the locales?

    Most people actually evaluate this in code, and we have not expressed it clearly
    in terms of a property. It would be something like:

    code point =>
        (
            (lowercase, (locale, condition, result), (locale, condition,
    result),...),
            (titlecase, (locale, condition, result), (locale, condition,
    result),...),
            (uppercase, (locale, condition, result), (locale, condition,
    result),...)
        )

    Now, in practice, we don't really have cases where a character maps differently
    (from the default) according to two different locales or conditions, or more
    than one casing condition.

    So faced with lines like the following:

    0049; 0131; 0049; 0049; tr Not_Before_Dot; # LATIN CAPITAL LETTER I
    0049; 0131; 0049; 0049; az Not_Before_Dot; # LATIN CAPITAL LETTER I

    the value, if treated as a single property value is really collapsed to:

    U+0049 -> [uppercasing, tr OR az, Not_Before_Dot, U+0131]

    >
    > Theo
    >
    >
    >
    >



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