[Top] [All Lists]

Re: character sets

1991-05-08 22:27:16
[..lots of text deleted, here and there..]

# However, there are some things that we need to include in the header
# if we want the software to behave intelligently. For example, if we
# want our UA to automatically convert Quoted-Readable to, say, Latin-1,
# we will need something like:
#       Content-Encoding: Quoted-Readable
# so that strings such as "J&o/rn" can be converted. This can probably
# be made to work even if the string is in EBCDIC. However, if we use
# hex in the quoted encoding, ASCII strings that get converted into
# EBCDIC may lose their meaning. E.g. "J\F8rn": if this string is in
# EBCDIC and you convert the \F8 to one byte, you probably won't get the
# o-slash that was intended.
# Of course, if you know that the original code was Latin-1, you could
# still do something intelligent with "\F8" even if it's in EBCDIC.
# Therefore, a hex encoding must be accompanied by an indication of the
# original codeset. For example:
#       Content-Encoding: Quoted-Printable, Latin-1

I think Mark Crispin said in the prior message that it should be
specified by a resource-ref; something like..

        Content-Type: TEXT;Latin-1
        Content-Encoding: Quoted-Printable

So the UA can convert the quoted-printable text to 8 bit text,
and then convert the 8 bit Latin-1 to whatever the user wants.

# So what's my conclusion? If we allow people to send whatever they
# want, and we don't mark the text with a character encoding header, how
# can we interoperate?

I would like to see the character set information to be gotten from
setlocale(), or something similar.  So we have things like..

        Content-Type: TEXT;en_US.88591
        Content-Type: TEXT;ja_JP.sjis
        Content-Type: TEXT;ja_JP.ujis
        Content-Type: TEXT;ja_JP.10646

Then a Shift-JIS user can send Japanese mail to a UJIS user, and no
matter what Content-Encoding is used (Quoted-Printable or ISO2022),
the UA can do the code conversions correctly and the user can read
the mail.

Hitoshi Doi, International Systems Engineering    
Japan Research and Development Center
Digital Equipment Corporation Japan

<Prev in Thread] Current Thread [Next in Thread>