Re: compatibility between unicode 2.0 and 3.0

From: Markus Scherer (markus.scherer@jtcsv.com)
Date: Thu Feb 06 2003 - 21:20:34 EST

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    Doug Ewell wrote:
    > That said, there are certain conventions for certain ranges of code
    > points. For example, the range from U+0590 through U+08FF is marked in
    > the Roadmap as being reserved for right-to-left scripts, and IIRC there
    > are ranges reserved for invisible formatting and control characters
    > (U+206x and U+FFFx). ...

    Note that Unicode provides property values like the bidi class and Default_Ignorable_Code_Point even
    for unassigned code points.

    The only "magic" for implementers of Unicode property APIs is that some of the UCD files do not
    explicitly list properties for unassigned code points, or which is the default value for
    not-mentioned code points in general. Sometimes one has to check the header of the file or the
    chapter in the Unicode book, etc. I believe this is being fixed for 4.0.

    *Users* of such low-level property APIs need not care about where the implementers get this data, of
    course.

    markus

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