> And in fact, it's still possible. Nothing stops Jacob or anyone else from
> defining a new type of body part that supports text of multiple character
> encodings. The challenge is in making it technically sound and enough of a
> win over HTML (which is already widely supported) that people want to
> implement it and use it.
Are not Japanese people already doing this in order to
allow Japanese e-mail to contain a mixture between English
and Japanese text, by using ISO 2022 character set switch
marks in the text.
Not really. You're referring to the iso-2022-jp charset, which is basically a
combination of the ASCII, JIS X 0201, and JIS X 0208 coded character sets
using the ISO-2022 character encoding scheme. It does not allow for selection
of arbitrary coded character sets, let alone the selection of multiple
charsets.
While ISO-2022 does allow for the use of many (but by no means all) coded
character sets, the idea of defining a text format or a charset that allowed
for selection of arbitrary coded character sets was considered early on in the
MIME work -- and rejected. Several other charsets based on ISO-2022 have
been defined, but they all have the same sort of structure as iso-2022-jp.
Ned