Re: CJK Unified Ideographs Range

From: Kenneth Whistler (
Date: Fri Feb 21 2003 - 15:12:16 EST

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    Andrew followed up:

    > Maybe what I'm really trying to ask is, if sometime in the future we
    > start to run out of space in the BMP, could U+9FB0 through U+9FFF be
    > reallocated to some new script, or is the allocation of these 80 codepoints to
    > the CJK block permanent and irrevocable ?

    Please study the roadmap for the BMP:

    There are many additional minority scripts slated for BMP
    allocation, but it is (in my opinion) unlikely that the proposals
    for more than a half-dozen or so of them will make it through
    the standardization process by the time Unicode 5.0 eventually
    rolls around. Other than these additional scripts, which are
    already catalogued and in various stages of research, most
    additions to the BMP at this point consist of random odd
    symbols, occasional punctuation, a few archaic or otherwise
    rare characters in existing scripts, and so on -- and those are
    just stuffed into gaps in the existing blocks.

    Han character encoders already have 1000's of code points on
    Plane 2 to play around with -- and Plane 3 to spill over into
    when they fill Plane 2. The problem with Han encoding is to
    constrain the costs of continuing to encode 1000's more variants
    of existing characters as independently encoded characters,
    rather than worrying about the space to encode them.

    The 80 code points in U+9FB0..U+9FFF *might* be used for something
    in the future -- most likely for some bunch of CJK characters
    which for some currently unforeseen reason gains some political
    traction to place them on the BMP. But realistically, by the time
    such an event could occur, it won't seriously matter to
    CJK implementations whether such additions are in the BMP
    or Plane 2 or Plane 3, since they will already be implementing
    Plane 2.

    In any case, let me assure everyone that with the discipline
    established by the roadmaps for future allocation, space on
    the BMP is well down on the list of serious concerns in the
    SC2/WG2 committee. And in the Unicode Technical Committee, it
    is hardly even on the radar, compared to many other issues
    of much greater concern to that committee about the maintenance
    and extension of the Unicode Standard.


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