OK, let me try to clarify what I meant about ISO-IR-n. Let's start
with Latin-1 as an example. This is used as an 8-bit code, maximally
with C0, G0, C1 and G1 (though C1 may not be as frequently used -- I
don't know), so the registration numbers would be something like:
C0 control ISO-IR-1
G0 graphic ISO-IR-6
C1 control ISO-IR-77
G1 graphic ISO-IR-100
These numbers may be wrong, but the point is that "Latin-1" (whatever
*that* is) can be construed to include the above *four* sets. So how
would you write the header?
Content-Type: ISO-IR-1,6,77,100 ???
This is why I'm suggesting a separate Content-Type for Latin-1.
Similarly, the Japanese use more than one character set at once, so I
want a separate Content-Type for them. (I suggested the name
message2022. More about this in another message.)
Now to come back to ISO 646. These national variants are used as 7-bit
sets, with the "usual" set for C0. So my suggestion was to fix the C0
part, and make the G0 part variable, the value given by the header:
Content-Type: ISO-646-<registration number>
I hope this is clear now.
Erik
PS I foresee a problem with the Norwegian ISO-IR-60, however. This is a
96-character set, and as such may not be used in G0 (if you follow ISO
2022 strictly). Uh-oh...