Re: ? Reasonable to propose stability policy on numeric type = decimal

From: Mark Davis ☕ (mark@macchiato.com)
Date: Mon Jul 26 2010 - 10:03:56 CDT

  • Next message: John H. Jenkins: "Re: ? Reasonable to propose stability policy on numeric type = decimal"

    > the analogy to the existing such policies seems strained at best.
    > In practice this is what we do. I just don't think we need more rules.

    There are many such policies: see
    http://www.unicode.org/policies/stability_policy.html#Property_Value (or the
    more accessible
    http://www.unicode.org/policies/property_value_stability_table.html)

    <http://www.unicode.org/policies/stability_policy.html#Property_Value>The
    policies are vital; their purpose is to ensure that programmers know what
    they can depend on in their implementations from version to version, and
    what they can't. There are many, many 'accidental' relationships between
    Unicode character properties that happen to be true at this point in time,
    but which the consortium has no commitment to maintain in future versions.
    On that page, and others like
    http://www.unicode.org/policies/locales_stability.html, are the
    relationships that programmers can depend upon, and build into their
    implementations without fear that they many change across versions. See also
    the new proposal for http://www.unicode.org/review/#pri173

    Karl,

    While it has been a good discussion, if you want to make a proposal for such
    a policy you'll want to propose it to the UTC, using the feedback form at
    http://www.unicode.org/reporting.html. (Posting to this list doesn't
    suffice.) If the UTC decides to approve it then formally it would then
    recommend adoption to the Unicode officers.

    As far as the formulation, rather than:

    "New scripts or forms (like mathematical mono space) that have decimal
    numbers will be assigned so that those decimal numbers occupy at least 10
    contiguous code points such that the code point for DIGIT ONE = 1 + the code
    point for DIGIT ZERO, etc."

    The end result would probably be phrased as a relationship between the
    properties Numeric_Type and Numeric_Value, not what can be encoded where,
    perhaps something like:

    For each character with Numeric_Type = Decimal (nv=de) and Numeric_Value =
    N: if N > 0 then the preceding character (in code point order) has nv=de and
    nv=(N - 1); if N < 9 then the following character has nv=de and nv=(N + 1).

    There would, of course, be implications for allocation, like for other
    policies.

    Hope this helps,

    Mark

    *— Il meglio è l’inimico del bene —*

    On Mon, Jul 26, 2010 at 06:55, John Burger <john@mitre.org> wrote:

    > Mark Davis ☕ wrote:
    >
    > From just a quick scan, it appears that they are currently all contiguous
    >> within their respective groups. If we were to impose a stability policy, it
    >> would be a constraint on the general_category: we would not assign
    >> general_category=decimal_number to any character unless it was part of a
    >> contiguous range of 10 such characters with ascending values from 0..9.
    >>
    >
    >
    > Whether such a policy makes sense, I'm not clear on why it would be called
    > a "stability" policy - the analogy to the existing such policies seems
    > strained at best.
    >
    > - John D. Burger
    > MITRE
    >
    >

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