Unicode planes (was Re: Tahano Nuhicamu font)

On 1/13/06, Paul Bennett <paul-bennett@...> wrote:
> there are
> about 65,530 more Planes of 64K codepoints each that are yet to be
> defined, and which probably will not be defined any time soon.
No, they *are* defined -- at least, inasmuch as it has been decided
that no code point will ever be allocated past U-10FFFF, ever.

If I recall correctly, there used to be another huge private-use plane
somewhere beyond that point (though no other definitions, even vague
ones) in Unicode, but ISO-10646 only defined 17 planes, and when
Unicode was brought into step with ISO-10646 they decided to limit
themselves to that as well.

I suppose in one way, one could say that that means that every
representable code point beyond U-10FFFF is free for use (since it'll
never be allocated an official meaning), but then you couldn't say you
were using Unicode; I don't know, but can imagine that there might be
software out there that considers code points beyond U-10FFFF an
error, and rightly so, from the point of view of Unicode.
--
Philip Newton <philip.newton@...>