Re: What is the principle?

From: Mark Davis (
Date: Wed Mar 31 2004 - 17:27:24 EST

  • Next message: Philippe Verdy: "Re: Doing Markup in Plain Text: A Modest Proposal for Planes 4-B of Unicode"

    While I disagree with most of what you've said on this list, it is not an
    unreasonable proposal to change the default properties for some ranges of the
    private use blocks. I don't think that this would, in practice, really disturb
    any applications, because of #1 below.

    I have, however, a few observations.

    1. PUA properties, as is clear from Ken's excellent descriptions, are simply
    defaults. With the exception of normalization, no Unicode implementation is
    required to observe them. So even if this change is made, any conformant
    implementation is free to simply ignore it and just assign its own properties.
    This would not be a magic wand.

    2. Unicode properties are not sufficient for rendering. With technologies such
    as Apples, all of the other work can be done in a font. With OpenType, most but
    not all can -- in particular, reordering has to be done by the application/OS.
    So complex scripts that require reordering still would not be interchangeable
    without private agreement.

    3. Even excluding the normalization properties and other obvious inapplicable
    properties (such as name or age), there are some 50-odd possible character
    properties, many of them with multiple possible values: see

    A concrete proposal would have to specify exactly which properties were
    relevant, and what the values are for the proposed ranges. (Clearly an even
    partition according to all the possible combinations would be completely
    impractical.) If the goal is rendering, this means looking at the possible
    combinations of properties that are relevant for rendering and proposing a
    division that makes sense.

    ► शिष्यादिच्छेत्पराजयम् ◄

    ----- Original Message -----
    From: "Peter Kirk" <>
    To: "Rick McGowan" <>
    Cc: <>
    Sent: Wed, 2004 Mar 31 16:24
    Subject: Re: What is the principle?

    > On 31/03/2004 12:40, Rick McGowan wrote:
    > >Peter Kirk wrote...
    > >
    > >
    > >
    > >>... I have a real requirement. The UTC has the power to meet my requirement,
    > >>and to do so rather simply. I am asking them to meet it.
    > >>
    > >>
    > >
    > >Actually, you are not asking UTC anything. You are discussing the PUA on a
    > >public-access mail list. There's a big difference. This *is* the place to
    > >discuss as you are doing, and a good place to formulate your positions for
    > >eventual submission of a proposal, if any.
    > >
    > >
    > Thanks for the clarification. I was aware of the distinction, and was
    > using "am asking" loosely. I am undecided yet whether to make a formal
    > proposal. Ken seems to suggest that this would be a waste of time -
    > although I can see some advantages in obtaining a formal rejection. I
    > wonder if anyone else on the UTC or associated with it might give some
    > hope for such a proposal?
    > --
    > Peter Kirk
    > (personal)
    > (work)

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