W3C home > Mailing lists > Public > www-math@w3.org > February 2008

RE: Arabic math

From: Richard Ishida <ishida@w3.org>
Date: Fri, 29 Feb 2008 11:36:55 -0000
To: "'cj'" <cj@mb-soft.com>
Cc: <www-math@w3.org>
Message-ID: <000001c87ac7$633c35b0$29b4a110$@org>

Note that if you list out characters in Unicode in the order they appear in
computer memory, you would see the following (read top to bottom, where
upper case represents Arabic letters):

A
R
A
B
I
C

1
2
3
.
4

T
E
X
T

This is also the order in which a simple phrase like that would normally be
typed.

When that is displayed, however, you see

TXET 123.4 CIBARA

This is achieved at run time, as characters are typed, using the Unicode
bidirectional algorithm and the rendering software applying rules to the
text to reorder.  The order of characters in memory remains unchanged.  The
position of the dot will change as you type and the system works out whether
this is a sentence-final period or decimal point.  For more information see
http://www.w3.org/International/articles/inline-bidi-markup/

RI

============
Richard Ishida
Internationalization Lead
W3C (World Wide Web Consortium)
 
http://www.w3.org/International/
http://rishida.net/blog/
http://rishida.net/

 
> -----Original Message-----
> From: www-math-request@w3.org [mailto:www-math-request@w3.org] On Behalf
> Of cj
> Sent: 26 February 2008 20:21
> To: www-math@w3.org
> Subject: Arabic math
> 
> 
> Your presentation on Arabic math notation is excellent.
> 
> However, I have one issue that I think is important, and I do not see that
> you have addressed it there.
> 
> It has to do with ltr and rtl presentation of Arabic numbers.  The most
> obvious example I have thought of is this sentence:
> 
> The circumference of a circle is 3.1415926535 times the diameter.
> 
> If an Arabic writer translates that sentence into Arabic, the wording
> begins
> flowing from right to left.  But if it is required that the value of pi is
> presented left-to-right, then the writer would have to skip ahead AN
> UNSPECIFIC AMOUNT OF SPACE in order to then write the value in the space.
> That seems immensely illogical and inconvenient to me.  I would think that
> all Arabic writers would necessarily write that sentence, words and
> numbers,
> from right-to-left.  In other words, after that writer writes the Arabic
> words for "circle is", he would next write the 3 immediately to the left
> of
> it, then the punctuation (whether decimal or comma) then the 1, etc.
> 
> It is the only logical way where an Arabic writer would not have problems
> in
> providing appropriate space for the number value.  When he is done writing
> down the numeric value, with the final 5, at the left-hand end of where he
> then was, he would simply and logically continue on with the following
> words, "times the", continuing leftward.
> 
> I realize that does not always seem to be done.  But it seems the
> "logical"
> way that schoolchildren are taught the circle circumference relationship,
> doesn't it?
> 
> Carl Johnson
> (Nuclear Physicist)
> 
> 
Received on Friday, 29 February 2008 11:33:44 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Saturday, 20 February 2010 06:13:00 GMT