That's interesting - I had assumed that there was no maximum to the scalar values in Unicode, just that each encoding had its limits.
In my copy of The Unicode Standard Version 3.0, I can't find an explicit statement that scalar values in Unicode are only in the range U+0 to U+10FFFF - but this could be deduced from the fact that all the encodings in the Standard (UTF-8 and UTF-16) are limited to this range. It looks like UCS-2 and UCS-4 are defined in ISO 10646. Does that standard restrict the valid range of UCS-4 to 0..10FFFF? If not, does this represent a significant divergence between Unicode and ISO 10646? (Sorry if these are well-known issues - I've only been on the list for a couple of months) Thanks! - rick -----Original Message----- From: Kenneth Whistler [mailto:[EMAIL PROTECTED]] Sent: Tuesday, 18 December 2001 10:09 To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Astral planes (was: RE: Plane One use, was Re: HTML Validation) Clive said: > But I never did figure out if everything above Code Plane 16 was above > or still below the Heaviside Layer... ;-)} As for the cats, in "Up up up past the Russell Hotel, up up up to the Heaviside layer"? Actually, my surmise, given the fact that the code points past U+10FFFF are forever inaccessible, is that they lie beyond the event horizon. Not merely the event horizon of local black holes, as for Planes 2 and 3, which will be endless sinks for CJK encoding energy, pulling hapless encoders in and shredding them with infinite tides as they approach the danger zone. No-- rather, the event horizon of the entire character universe, beyond which we can detect nothing. Perhaps, however, from the murmer of chilled microwaves emanating from the vicinity of the noncharacters U+10FFFE and U+10FFFF, at the far nether reaches of the astral planes, we can find patterns that will allow us to interpret the earliest history of the character universe. --Ken
