Re: Difference between Bidi_Class 'R' and 'AL'

On Wed, 24 Aug 2011 08:35:48 -0700
"Doug Ewell" <doug_at_ewellic.org> wrote:

> UAX #44, Table 13 ("Bidi_Class Values") includes the following
> descriptions:
>
> R - Right_To_Left - any strong right-to-left (non-Arabic-type)
> character AL - Arabic_Letter - any strong right-to-left (Arabic-type)
> character
>
> But I can't find any definition, here or elsewhere, of what
> constitutes an "Arabic-type" or a "non-Arabic-type" letter.

Expanding on Mark's answer, the basic difference is whether a character
of Bidi class ET (percentage-type and currency symbols) when stored
before or after European or Persian etc. digits goes to their left or
right. For Arabic, these symbols are not part of the number; for
Hebrew, they are part of the number. I'm not I understand the effect on
ES (variants of plus and minus signs) - may be it says that 'e-less'
exponents in Fortran output go on the left in Arabic but on the right
in Hebrew and LTR scripts.

Richard.
Received on Wed Aug 24 2011 - 14:39:46 CDT