Property stability policy considered harmful

From: karl williamson (
Date: Wed Jul 08 2009 - 18:01:44 CDT

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    It appears to me that the stability guarantees that a property and
    property value alias will never be removed are worse than not having
    them. And the reason is that all code points they contain can simply be
    moved to another property (or property value) without violating the
    letter of the policy. This has happened with
    Script=Katakana_Or_Hiragana whose contents were all moved to Common in
    4.1, and it appears to be happening in 5.2 with ISO_Comment. If I have
    a program that is looking for a property that has become empty, I would
    rather know about it at compilation time rather than to have it go along
    and give wrong answers (perhaps subtly so).

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