From: Michael Everson <>
Date: Fri, 19 Aug 2011 15:33:38 +0100

On 19 Aug 2011, at 15:13, Doug Ewell wrote:

> The PUA is supposed to be a free and open sandbox, without reserved or allocated zones.

Nevertheless, inherent directionality is something that computers take notice of. There would be no harm in having a RTL PUA area.

> My question would be why the PUA is designated as 'L' by default at all, instead of, say, 'ON'.

Since it is, there is a need for an 'R' area. I can think of several scripts in the CSUR which could make use of that, for instance.

> So your private agreement, in addition to specifying the meaning of your
> PUA characters and probably some sample glyphs, can also specify their
> properties, overriding the default properties.

Gods know I wouldn't have any idea how to get my operating system to honour such a declaration.

> But these lines in
> UnicodeData.txt:
> E000;<Private Use, First>;Co;0;L;;;;;N;;;;;
> F8FF;<Private Use, Last>;Co;0;L;;;;;N;;;;;
> do present the impression that these code points are somehow reserved
> for strong-LTR characters, and also for non-reordrant characters (i.e.
> no combining marks), neither of which is true.


> There's a lot of misinformation and FUD about the PUA, and unfortunately
> I expect at least one response of the form "The PUA is evil, don't use
> it," which accomplishes very little.

I just think we need some PUA that's RTL.

Michael Everson *
Received on Fri Aug 19 2011 - 09:34:39 CDT

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