Re: Multiple private agreements (was: RE: Code pages and Unicode)

From: Philippe Verdy <>
Date: Wed, 24 Aug 2011 04:29:58 +0200

2011/8/24 Doug Ewell <>:
> Coordinating private agreements so they don't conflict is clearly the
> ideal situation.  But many different people and organizations have
> already claimed the same chunk of PUA space, as Richard exemplified
> yesterday with his Taiwan/Hong Kong example.  There is no standard way
> to display:
> (1) a plain-text file
> (2) using only plain-text conventions (i.e. not adding rich text)
> (3) which contains the same PUA code point with two meanings
> (4) using different fonts or other mechanisms
> (5) in a platform-independent, deterministic way
> One or more of the numbered items above must be sacrificed.

The only numbered item to sacifice is number (3) here. that's the case
where separate PUA agreements are still coordinated so that they don't
use the same PUA assignments. This is the case of PUA greements in the
Conscript registry.

With only this exception, you can perfectly have separate agreements
(using multiple fonts transporting them), for rendering a plain-text
document. Of course the PUA only agreement stored in the font are the
set of glyphs, and the display properties. Other properties (for
collation, case mappings, text segmentation, and so on...) are not
suitable for being in the font, but they are not needed for correct
editing (without automated case changes) or for correct rendering.
Received on Tue Aug 23 2011 - 21:34:03 CDT

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