Re: Yerushala(y)im - or Biblical Hebrew

Date: Wed Jul 23 2003 - 18:46:04 EDT

  • Next message: John Hudson: "Re: Yerushala(y)im - or Biblical Hebrew"

    Peter Kirk wrote on 07/23/2003 09:24:12 AM:

    > From Unicode 4.0 section 3.11,
    > "The particular numeric
    > value of the combining class does not have any special significance; the
    > intent of providing the numeric values is /only/ to distinguish the
    > combining classes as being different, for use in equivalence
    > comparisons. ... The canonical order of character sequences does /not/
    > imply any kind of linguistic correctness or linguistic preference for
    > ordering of combining marks in sequences." There is therefore no reason
    > for combining classes to reflect ordering.

    But, the combining classes do have to reflect relative visual positions wrt
    the base -- that's what determines which things do or do not interact
    typographically. (Things that are above right will interact typographically
    with one another because they are competing for the same visual space, but
    not with things that are above, above left, below right, etc.) The classes
    will define *some* order, and as the classes are visually based, that order
    cannot be the logical order for both RTL and LTR text.

    > The problem, if there is one,
    > is with rendering software which expects to receive an input stream in a
    > logical order although Unicode implies that the order is arbitrary,

    No, the problem I'm referring to has to do with editing, when certain
    protocols recommend (and all but guarantee) that data be stored in a
    particular order. While the particular numerical values of combining
    classes are of no special significance and were not intended for anything
    more than to distinguish between different classes for use in equivalence
    comparisons, is just happens that that order will be used for storage order
    of data, and that will be the visual LTR order, making it the opposite of
    what users will likely think in terms of for RTL text.

    So, even if rendering software is performing its own reordering, the issue
    I'm trying to point out is that *editing* software may also need to do its
    own reordering in order to provide the kind of editing experience that
    users expect. Otherwise, users may have a difficult time knowing what order
    to type things, and what will get deleted the next time they backspace.

    - Peter

    Peter Constable

    Non-Roman Script Initiative, SIL International
    7500 W. Camp Wisdom Rd., Dallas, TX 75236, USA
    Tel: +1 972 708 7485

    This archive was generated by hypermail 2.1.5 : Wed Jul 23 2003 - 19:36:09 EDT