[Python-3000] Support for PEP 3131

[Jim Jewett]

On 6/2/07, "Martin v. Löwis" <martin at v.loewis.de> wrote:

> I'm unsure whether there are cases where
> the standard BIDI algorithm would produce incorrect results;

Yes, but I'm not sure any of those cases are appropriate for
programming language identifers.

Quoting from introduction to Unicode Annex 9:

"""
However, in the case of bidirectional text, there are circumstances
where an implicit bidirectional ordering is not sufficient to produce
comprehensible text
"""

Neither the example given (mixed-script part numbers, section 2.2),
nor those I could come up with (all involving archaic scripts) were
appropriate for variable *names*.

> it's certainly the case that not all tools implement it correctly,
> so the control characters can help those tools (assuming the
> tool implements the control character at least).

To be honest, that is probably what I would do; I'm not quite sure I
even understand the correct algorithm for numbers.

-jJ