Re: Hexadecimal

From: John Cowan (cowan@mercury.ccil.org)
Date: Sat Aug 16 2003 - 15:19:33 EDT

  • Next message: Michael \(michka\) Kaplan: "Re: Hexadecimal"

    Pim Blokland scripsit:

    > Besides, your example is proof that the implementation can change;
    > has to change. Where applications could use 8-bit characters to
    > store hex digits in the old days, they now have to use 16-bit
    > characters to keep up with Unicode...

    You are confusing the *representation* of characters with the *choice*
    of characters. The representation of characters for hex digits can and
    does change: it can be ASCII, EBCDIC, or Unicode. The choice of
    characters is fixed: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A/a, B/b, C/c, D/d, E/e,
    F/f.

    > > There is also a HUGE semantic difference between D meaning the
    > > letter D and Roman numeral D meaning 500.
    >
    > and those have different code points! So you're saying Jill is
    > right, right?

    No. The Roman numeral characters are encoded solely for compatibility with
    East Asian character sets. (The same is true of the KELVIN SIGN.)

    > What we're talking about is different general categories, different
    > numeric values and even, oddly enough, different BiDi categories.
    > Doesn't that qualify for creating new characters?

    As a practical matter, trying to go through all legacy texts (now including
    legacy Unicode texts!) and disambiguate every instance of A-F/a-f between
    alphabetic and hexanumeric uses would be inconceivable. The justification
    for not splitting off Turkish i and I from general Latin, due to their
    unusual case mappings, is exactly the same.

    -- 
    If you have ever wondered if you are in hell,         John Cowan
    it has been said, then you are on a well-traveled     http://www.ccil.org/~cowan
    road of spiritual inquiry.  If you are absolutely   http://www.reutershealth.com
    sure you are in hell, however, then you must be         jcowan@reutershealth.com
    on the Cross Bronx Expressway.          --Alan Feur, NYTimes, 2002-09-20
    


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