Re: Why 17 planes?

From: Philippe Verdy <>
Date: Wed, 28 Nov 2012 09:28:13 +0100

Note that I ma not suggesting any "Unicode/10646-compatible framework" (or
even standard) and I have no project to define one myself. But there's
absolutely nothing that Unicode/ISO/IEC/10646 can forbid for such thing to

The only point of resistance will be when those other frameworks or
standards will want to be granted an allocation for a block of characters
in the current standard for supporting their extension in a standard
codepoints range, instead of in an existing PUA range like they can do
today as they want without asking your permission. Then the current policy
may be challenged according to its existing rules : demonstrated usage, and
an agreement about common properties. It will then be difficult to refuse
this non-PUA grant to them.

Other challenges will be:
- (1) to limit the current explosion of encoding requests for large sets of
pictograms (here again an external registry for pictograms using an
extension mechanims not requiring large block allocations in the current
standard, could be helpful),
- (2) and how to limit the proliferation of encodings in CJK blocks: some
encoding frameworks may need to appear to not encode each new signogram,
but a formal description of it (for now the IDS are insufficient), or an
extension mechanism like suggested with the external registry.

And even without changing anything to existing UTF's, strings of characters
taken from a smaller block in the supplementary planes may be used to
implement these large extensions (after all this is already what is
happening with hieroglyphs). Unicode for now describes this process as an
"upper layer protocol", but without integrating any one in its standard..
for now, which is still challenging for interoperability between these
upper layer protocols).

2012/11/28 Doug Ewell <>

> Philippe Verdy wrote:
> And it will still remain enough place in the remaining planes to
>> define later a few more surrogates of a new type, if really needed for
>> a future, upward compatible, standard if it ever comes to reality
>> such as having an open registry of corporate logos or glyph designs,
>> managed by registrars, and served by Internet like Internet domain
>> names (up to the online delivery of these glyphs or logos with
>> "Internet-hosted fonts"), i.e. for encoding objects that won't be
>> worth the need to warranty a long term stability within Unicode/ISO/
>> IEC 10646 themselves, as these encoded objects will depend largely on
>> the lifetime of exclusive IP rights and are already not in scope of
>> Unicode/ISO/IEC 10646. And when these technolgoies will be developed,
>> nothing will prevent the Unicode/ISO/IEC 10646 standards to make a
>> reference (later) to these mechanisms (for the online delivery of
>> compatible fonts supporting these standards, both open fonts, or fonts
>> with private designs, presented as a collection of glyphs in this
>> external repertoire, plus registered selection rules).
> Lots of things in the world have been encoded, or could benefit from being
> encoded.
> There is no need for things that are *not characters* in the Unicode/10646
> sense to be encoded either directly in Unicode/10646 itself, as others have
> suggested, or in a Unicode/10646-compatible framework, as you appear to
> suggest.
> It is perhaps a tribute of some sort to the elegance of Unicode/10646 that
> people seem to want to use it to encode things that are so desperately far
> out of its scope.
> --
> Doug Ewell | Thornton, Colorado, USA
> | @DougEwell
Received on Wed Nov 28 2012 - 02:31:22 CST

This archive was generated by hypermail 2.2.0 : Wed Nov 28 2012 - 02:31:22 CST