Date: Tue Feb 22 2005 - 03:22:03 CST
Please note clearly the distinction between my main proposals, which should be
implemented officially by Unicode, and this side issue of "Codepoint PUAs".
On this side issue, consider the following.
We add to Unicode a small block of "Private Differentiation Selector"
codepoints, which are to be totally ignored by everything except, optionally,
a customized smart font.
The users of Klingon now get together, and decide they are going to use
"Private Differentiation Selector 5" for Klingon.
They simply take the codepoints of the Latin letters which transliterate
Klingon, and pair "PDS 5" with each letter's codepoint.
Now, users with a smart Klingon font get Klingon glyphs. Users who lack a
smart font with Klingon glyphs automatically get the Latin transliteration. We
can also do useful things for learners, by dynamically switching the specified
font with DHTML in a Klingon learning Web page.
And there are absolutely no problems with a Korean character showing up in the
middle of their Web page -- as may currently occur with the PUA.
So we now see how a small block of codepoints, with almost zero impact on
processing, can vastly increase the usefulness of Unicode to real-world people.
What we have done is turn Unicode from a "one dimensional array" into a "two
dimensional array". The primary (and defaultable) glyphs and meanings get real
codepoints along the main axis, and secondary (and allowably ignorable) glyphs
and/or meanings get "differentiators" along the secondary axis.
That basic principal also applies to my main proposals, which would use other
sets of "differentiator" codepoints, assigned officially by Unicode.
It's an extremely useful and efficient system for dealing with things --
glyphs or meanings -- that have an identity as a "subset" of a real codepoint.
Doug Ewell wrote:
> Doug <UList at dfa dash mail dot com> wrote:
> > Though there is a second question of whether the Variation Selectors,
> > or a new block of differentiators, could be opened up for use as a
> > "PUA for each codepoint". This could allow user communities to set up
> > auxilliary unofficial standards (such as my Archaic Greek alphabets),
> > if Unicode chose not to take the effort in that regard. There would be
> > some other benefits in preventing PUA conflicts as well, whether user-
> > community standardized, or left to individual font use.
> If the things being proposed are private-use characters, forget about
> variation selectors and just use the Private Use Area. You can always
> publicize your code point assignments, which won't prevent someone else
> from using the same code points for something else, but may work well
> for a specific user community.
> -Doug Ewell
> Fullerton, California
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