RE: Hexadecimal digits?

From: Jim Allan (
Date: Mon Nov 10 2003 - 10:28:55 EST

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    Jill Ramonsky posted:

    > However, "File99A" (where A is a hex digit) should
    > sort (much) after both "File99A" (where A is a letter) and "File100".
    > The only way you can tell "File99(letter)A" apart from "File99(digit)A"
    > is by giving the two As different codepoints.

    And the only way you can tell 7 decimal from 7 hex is by giving 7 to
    different code points, that is File777 in hex should sort after File999
    in decimal.

    The proposal doesn't even think about something so simple.

    Think it through.

    We would also need to distinguish octal digits. And in some
    circumstances letters above "F" are used for representing numbers with a
    base above 16.

    In fact you can't tell the difference between hex and decimal
    consistently in printed plain text without some sort of conventional
    marker, e.g. a leading "0x" or "$" or "&H" or a following subscript
    "16". Similarly you can't tell the difference between a product code
    with mixed decimal digits and letters (as long as they don't go above
    "F") and a hex number without knowing the context.

    Using a different coding won't help if the characters *look* exactly the
    same on the page.

    You will still *need* some kind of marker (or strong context) so that
    the reader can distinguish hex and decimal. That marker is what
    indicates whether it is hex or decimal.

    Are people going to be happy with any programming language in which B12
    can be a variable or a hex number but there is no way to tell by looking
    at at the code? Are people going to be happy with a computer language in
    which 25 can be either hex or decimal as far as you can tell by looking
    at the code?

    Coding is for people, not computers.

    But if, as in current computer languages, there is a marker to tell
    whether a number is decimal or hex then you don't need separate coding
    for the letters representing digits. The marker indicates whether the
    number is decimal or hex.

    The proposal also ignores the fact that lower case letters are indeed
    often used in hex representation.

    Jim Allan

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