re: Roman numerals

From: verdy_p (
Date: Thu Feb 18 2010 - 12:09:13 CST

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    My feeling is that Roman numerals are only written with single letter digits, and that all other numerals are just
    precomposed for compatibility reason (notably JIS and other CJK encodings where they are encoded to be rendered in a
    single square).

    Except for use within CJK for rendering within the square of a CJK font, Roman numerals should not be precomposed.
    There will still be a compatibility mapping from these Roman numeral letters to Latin letters (they are anyway the
    same since the origin, and deviated only because of a prefered rendering for them in modern texts, where they should
    preferably not be cursive, and drawn with serifs even if the text is written with a sans-serif font), and some
    people now want to make them distinct from normal text (which are anyway not written in the Latin language).

    But if you look further in the past, you'll find many examples of Roman numerals written with a cursive script, and
    all the past script designs (including Fraktur, Caroline..), as well as in lowercase, possibly in italic and bold.
    The distinction with normal text was made by surrounding Roman numbers with an additional middle dot.

    You'll also note that Roman numerals also exist in small capitals (ordinal century numbers and subchapter numbers,
    but not millenium numbers and book numbers and main chapter numbers...). We can then go far into typographic
    conventions, which are not universal and language-dependant today.

    I really think that Roman numbers encoded with multiple letters should be avoided as much as possible, unless you
    are sure that you will never exceed twelve and you want to get a consistant look for the whole sequence up to that
    number (e.g. hours on a clock cycle, or month numbers). Avoid them for numbering king names, centuries, years.

    So, use the the single-letter Roman numerals and compose all numbers with them and yoiu won't get any more problem.
    Or use the normal Latin letters, and the rendering font and style of your choice, as well as the optional
    surrounding punctuation you may want.

    Collation is a separate issue : when this requires reordering letters or reinterpreting the whole number, this goes
    out of scope of the Unicode standard, and even from the UCA algorithm itself, because this is exactly the same
    problem for all numeral systems that are enough complete to require using a variable number of digits. This is a
    matter of semantic analysis of the decoded streams of characters and it highly depends on the language and on the
    conventional notation used, both of them being not encoded directly in plain texts.


    > Message du 17/02/10 22:38
    > De :
    > A :
    > Copie Ă  :
    > Objet : Roman numerals
    > You have Roman numerals beginning at (decimal) 8544 and 8560, but each only twelve. Are there elsewhere Roman
    numerals through 24? (I find it hard to search your website.) Note that the Italians already in the 14ht century
    built tower clocks with Roman numerals from I through XXIIII (with XVIII at the top, because they began the day at

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