Re: [Private Use Area] Audio Description, Subtitle, Signing

From: Kenneth Whistler (
Date: Thu Jul 17 2003 - 14:59:37 EDT

  • Next message: Michael Everson: "Re: [Private Use Area] Audio Description, Subtitle, Signing"

    William spilled another ocean of digital ink. Found bobbing
    in that ocean was the comment:

    > >Roozbeh and I assigned two unencoded characters for Afghanistan to
    > >the PUA, and we encourage implementors to use them until such time as
    > >the characters are encoded.
    > Yes. ... Now that at least one of them has been approved for
    > encoding by the Unicode Technical Committee there is now a long period of
    > waiting during which Private Use Area encoded data can be produced. This
    > does seem unfortunate and for individual symbols such as these I would hope
    > that the people who are in charge of Standards might like to consider asking
    > if the United Nations and the World Trade Organization could perhaps arrange
    > for some faster way of achieving agreement.

    *rolls eyes*

    It seems rather unlikely that getting the United Nations and the
    World Trade Organization involved in trying to amend JTC1 standards
    directives would be a recipe for speeding anything up. :-)

    > It does seem so very slow for
    > the twenty-first century with so many electronics communications facilities!
    > Why does legacy data have to build up and resolving the problem take so long
    > for just a few symbols?

    Because amending and updating a standard is effectively the same
    task whether it involves 1 additional character or 181 additional
    characters. There are a large number of stages, approvals, reviews,
    and other tasks involved -- which are there for a reason, to ensure
    the stability and orderly maintenance of the standard.

    > I would have thought that with a reasonable
    > infrastructure that those two code points could have been formally added
    > into regular Unicode and ISO within a couple of weeks.

    The whole idea of adding a couple code points this week and then a
    couple more next week, and then another next month, and so on is,
    well, just nuts. It would destroy effective version control and
    would create a situation where implementers were unsure just what
    was in the standard and when it would change further. It would
    *damage* the standard rather than improve anything.

    A character encoding standard is not just a laundry-list registration
    of characters that people happen to notice this week. As such, it
    is not advisable to create a mechanism whereby new characters
    are noticed, approved, and "registered" on a weekly basis.

    > An ocean of digital ink! I like that phrase.

    As well as producing the oceans, clearly.

    > That person added that people
    > have been telling me for a long time that PUA codes are not suitable for
    > interchange.

    Not suitable for *public* interchange, because, by definition, in
    public interchange the receiver will not be a party to whatever
    *private* agreement defines their usage, and so will not be able
    to interpret them.

    > That puzzles me, because I thought that it was alright to interchange
    > Private Use Area codes if there is an agreement as to their meaning in a
    > particular situation.

    Yes, a *private* agreement for *private* interchange. That, as Michael
    tried to tell you, is why we call them *private* use characters.

    > Also, Unicode 3.0 mentions the possibility of
    > publication of Private Use Area assignments

    Anyone is free to publish anything they wish, including lists of PUA

    > in the section on the Private
    > Use Area.

    But the Unicode Consortium will not publish such lists in the
    Unicode Standard or on its website in any official way.

    > So what is the official position please?

    I just stated it. If you want chapter and verse:

    "All code points in the blocks of private-use characters in the
    Unicode Standard are permanently designated for private use--no
    assignment to a particular, standard set of characters will ever
    be endorsed or documented by the Unicode Consortium for any of
    these code points."
                             -- The Unicode Standard, Version 4.0,
                                Section 15.7, "Private-Use Characters",
                                p. 398, 2003 [forthcoming]

    > This is important to me because I
    > have been proceeding in the belief that suggesting three Private Use Area
    > code points for use in interactive television systems is entirely proper and
    > compliant with Unicode and the ISO standard.

    It is. But other participants on this email list have been telling
    you that they are not interested in your *particular* use of
    private use characters.


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