Is ISO 2022 for Japanese a subset of ISO 10646?
No. (Keld already explained this.)
If so, I have no
problem listing is as a "regional subset" of the "full" character set.
So does this mean that you do have a problem listing the Japanese form
of ISO 2022 if it isn't a subset of 10646?
I think that the restricted form of ISO 2022 (as the Japanese use it)
should be added to the list. Whether or not the RFC states that it is
required is another issue, but I think it should at least be listed.
Actually, I think there are at least two kinds of ISO 2022 that we
might like to consider for adding to the list.
One is just straight, full ISO 2022. As far as I'm concerned, this one
should just be `optional' (if we are to choose from
required/recommended/optional).
The other is the one I'm more interested in, and I'm suggesting that
we call it `message2022' (or MESSAGE2022). I.e. it is the form of ISO
2022 that we use in email messages and network news articles.
The definition I'm thinking of is essentially the same as the Japanese
definition. It uses only the C0 and G0 sets, and allows switching of
the G0 set only. Only the designation sequences are allowed. No
locking shifts, single shifts, shift-in, and shift-out are allowed.
This means that message2022 is a simplified form of ISO 2022, and
therefore much easier to implement.
How do other people feel about this?
Erik