srivas sinnathurai 於 2011年8月19日 上午9:40 寫道： > Why this suggestion? > With current flat space, one code point is only allocated to one and only one > purpose. > We can run out of code space soon. >
There are a couple of problems here. We currently have over 860,000 unassigned code points. Surveys of all known writing systems indicate that only a small fraction of these will be needed. Indeed, although it looks likely that Han will spill out of the SIP into plane 3, all non-Han will likely fit into the SMP. (Michael, you can correct me on this if I'm wrong.) Even if we allow for the possibility that there are a lot of writing systems out there we don't know about, there would have to be a *lot* of writing systems out there we don't know about to fill up planes 4 through 14. If the average script requires 256 code points, there would have to be some 2800 unencoded scripts to do that. Moreover, it's taken us 20 years to use 250,000 code points. Even if that rate remained steady (and it's been going down), it will take us something on the order of a century to fill up the remaining space, if that's even possible, and that hardly qualifies as "soon." And there already is a code page switching mechanism such as you propose. It's called ISO 2022 and it supports Unicode. In order to get the UTC and WG2 to agree to a major architectural change such as you're suggesting, you'd have to have some very solid evidence that it's needed—not an interesting idea, not potentially useful, but seriously *needed*. That's how surrogates and the astral planes came about—people came up with solid figures showing that 65,536 code points was not nearly enough. So far, the evidence suggests that we're in no danger of running out of code points. ===== Siôn ap-Rhisiart John H. Jenkins jenk...@apple.com
