From: jcowan@reutershealth.com
Date: Thu Apr 29 2004 - 15:37:43 EDT
Language Analysis Systems, Inc. Unicode list reader scripsit:
> So what kind of things might people want to do with PUA code points?
One significant thing they want to do with them is to use them to represent
the existing PUA areas in non-Unicode CJK standards, many of which have
various overlapping de facto assignments to Han characters.
> 2) Leave the current PUA alone, but set aside a new PUA, say Planes 12
> and 13. This solves the existing-use problem, but you still have the
> question of just how you subdivide the range, and it starts to cut down
> significantly on the code points available for actual standardization.
This last point isn't very strong. Nobody who's actually considered the
problem thinks we are going to get past plane 3; all counterarguments
known to me are of the form "Finite allocations are always too small
in principle; we have overrun ASCII and IP version 4 and so on, and so
we need indefinite extensibility." This argument just doesn't apply to
characters, short of joining the Galactic Empire.
> 6) Use markup or other fancy-text mechanisms to override the default
> properties. There are plenty of controls for controlling
> directionality, cursive joining, and line breaking. It may be
> inconvenient to use them, but it seems like a viable workaround while
> waiting for something to get into Unicode, and there's no implementation
> lag. What problems do the existing mechanisms not solve? Maybe the
> discussion should focus on this question-- are there mechanisms that
> should be added to Unicode or some markup language to help enable some
> of these scripts?
The obvious problem is that there is no way to force something to be
a combining character of class X. Allocating 256 marker characters in
Plane 14 would solve this, but probably at an unacceptable cost in
implementation complexity.
-- There are three kinds of people in the world: John Cowan those who can count, http://www.reutershealth.com and those who can't. jcowan@reutershealth.com
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