Re: Filtering and displaying untrusted UTF-8

From: verdy_p (
Date: Mon Dec 28 2009 - 18:16:45 CST

  • Next message: verdy_p: "Re: Filtering and displaying untrusted UTF-8"

    "Andrew West"
    > Asmus's comment also applies here. There is no guarantee that Planes
    > 3-13 will always remain unassigned, and in fact there is a very strong
    > probablility that Plane 3 will be assigned before very long.

    True: the TIP will be used for newer (ancient) ideographic scripts (those that are roadmapped concern old CJK
    variants) (plane 3)

    But it may also receive new blocks for Han ideographs when plane 2 will be full (this could happen when the "CJK
    Unified Ideographs Extension E" proposal will be written and finalized, but other blocks may be needed and allocated
    before Extension E will be final, because the Roadmap of Plane 2 is nearly full for non-compatibility CJK characters
    and will not allow new blocks as large as Extension E, whose maximum size has been predetermined): (plane 2)

    This last page clearly indicates that Plane 3 could be used for future Han characters, if the SIP (currently full at
    three quarters with the existing allocations and the current proposal for Extension D which is already approved by
    the UTC) proves to be insufficient.

    Other historical large scripts to encode may not all fit in the SMP (plane 1), if they need more extensions.

    And if large sets of Emoji symbols, or international sets of conventional symbols need allocations (road indicators,
    geographic symbols, new extensions for modern scripts like SignWriting, notational symbols used in sports, technical
    symbols, symbols for health and environmental hazards, chemical/physics symbols, symbols used in biology like floral
    structures, symbols for genetics, new symbols for application GUI on computing devices...), they may not fit there
    too... There may finally exist a future "extended symbols plane" (ESP: plane 4 ? Note that the abbreviation SSP is
    already taken by plane 14 for Supplementary Special-purpose Plane, but given that it will remain extremely small in
    the current roadmap, it could as well be used for symbols...)

    Finally, if you really want to filter the special plane 14, you'll exclude all the variation selectors supplement
    (but then why would you keep the first small block of variation selectors allocated in the BMP???)

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