RE: Colouring combining Marks (was: unicode Digest V5 #149)

From: Jony Rosenne (
Date: Tue Jun 21 2005 - 14:58:16 CDT

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    > -----Original Message-----
    > From:
    > [] On Behalf Of Doug Ewell
    > Sent: Monday, June 20, 2005 8:00 AM
    > To: Unicode Mailing List
    > Cc: Richard Wordingham
    > Subject: Re: Colouring combining Marks (was: unicode Digest V5 #149)
    > Richard Wordingham <richard dot wordingham at ntlworld dot com> wrote:
    > > As an aside, I'm beginning to get confused by the 'order'
    > terminology.
    > > I use to assume that visual order was the(?) orderly order the eye
    > > would follow when reading, but that does not seem to be so for RTL
    > > scripts!
    > > ...
    > > I suspect 'logical order' really just means, 'the order we like'.
    > Most of the time, when I see the term "visual order," the
    > writer really
    > means "left-to-right," which of course is absurd for Arabic and Hebrew
    > and such. I consider it a holdover from older computer technologies
    > that could only display things left-to-right, built by people for whom
    > LTR was the "normal" reading direction.
    > I'd prefer to see "visual order" used to mean the direction generally
    > appropriate for the script -- LTR for Latin, RTL for Hebrew -- but
    > without reordering or other details that break the normal
    > directionality. "Logical order" would be similar, but with these
    > details added. I'm sure an expert in Bengali or Tamil or Khmer could
    > come up with suitable examples.

    Let me explain the history.

    In the 1950's we used punched cards. There was no word processing or text
    processing, there were plug boards and one would wire the card column to a
    printer position.

    For Hebrew, we had to punch the text in reverse order, because the key
    punches were left to right and the only control was tab. So we wired the
    printers across and everything looked good.

    When computers came along this method had the additional advantage that
    sorting and merging worked fine. Most of the legacy mainframe data is still
    encoded this way.

    When mini computers with screens started to be used, their users preferred
    to store the Hebrew right to left, so they could display it easily. They
    modified their form editors to allow easy typing.

    PCs with DOS also mostly preferred right to left Hebrew. This also the
    official ISO/Unicode visual order.

    In visual, embedded numbers and English are typed reversed, in visual order,
    while in logical order they are typed naturally and the software does the
    RTL/LTR processing.


    > --
    > Doug Ewell
    > Fullerton, California

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