Re: Regulating PUA.

From: Adam Twardoch (
Date: Sun Jan 21 2007 - 11:12:00 CST

  • Next message: Eric Muller: "Re: Regulating PUA."

    If you define part of the PUA as non-character PUA in future, what will
    you do with applications and uses that currently use those PUA
    codepoints for character purposes? Will these applications and the
    existing documents suddenly become Unicode non-compliant?

    Many years ago, the Unicode consortium made a decision to declare a
    certain part of the encoding space "private", which implies that the
    consortium will not interfer with people’s use for this space. Now,
    suddenly starting to retroactively regulate this space would make no
    sense, and would go against the principle.


    Ruszlan Gaszanov wrote:
    > Unicode standard currently allows PUA (private use areas) for whatever anyone might want to use it. This tends to create problems, since, sometimes PUA code points are used for process-internal purposes and other times - for storing non-standardized character data. Because there is no way for users with a need to represent non-standardized character data to know which PUA code points some application might use for process-internal purposes and there is no way for an application designer which PUA code points someone might chose for encoding non-standard characters, this can various create issues.
    > So, why don't we split the PUA into character-PUA (reserved for representing non-standard characters) and non-character-PUA (reserved for process-internal uses)? For instance, we define the ranges of BMP PUA, which are known to be used by popular applications and the entire Plane 16 as non-character PUA, while reserve the rest of BMP PUA along with Plane 15 for encoding private characters exclusively. This way there would be no more confusion.
    > Also, if we define Plane 16 code points as reserved for process-internal use, we will no longer need to be able to interchange those code points, so future encodings schemes for that purpose could save an extra bit.
    > Ruszlán

    Adam Twardoch
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