# Re: correction (was: Not all Arabics are created equal...)

From: John Cowan (jcowan@reutershealth.com)
Date: Fri Jul 14 2000 - 11:54:00 EDT

Gregg Reynolds wrote:

> What counts (no pun intended) is the
> mathematical rule of evaluation, which says that the LSD position is ones,
> the next over is tens, then hundreds, etc.

That is no rule at all, but a tautology. If we wrote one hundred twenty three
as 321, the "3" would be in the LSD position aka the one's place.
In fact, if we wrote it as 132, the "3" would still be in the LSD position aka
the ones place.

The actual *rules* seem to be as follows:

1) all digit strings are expressed internally with the MSD first;

2) all digits strings are displayed with the MSD on the left (except Tengwar
digits, which aren't in Unicode yet);

3) when typing on a computer, Arabic-Indic digits slide leftward, whereas European
digits stand still;

4) when writing in any other way, Arabic-Indic digits are written by skipping
leftward for a sufficient distance to make room for the digits, and then writing
MSD-first.

> In Arabic, and Persian, and Urdu, etc., "first
> in reading order" means to the right of the remaining figures, and that
> means the LSD.

That is true only if you believe that the reading order of digits is necessarily
the same as the reading order of letters. Consider a digit-string such as a
phone number. How is it read? I will bet any reasonable amount that it is read
from left to right, such that 123-4567 means (and is dialed) "one two three,
four five six seven" rather than "seven six five four, three two one."

> So although
> Persian written forms are LSD first,

If they are physically written LTR on paper, and they are entered MSD-first
on a computer, and they are read (when interpreted as a digit string rather
than a numeral) LTR, then I think they are LTR = MSD first, despite the
undoubted RTL order of the surrounding text.

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