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Character-set header (was Re: Minutes of the Atlanta 822ext meeting)

1991-08-28 22:53:16
Issue 1) Character set designation in a new header line. There was
dis-satisfaction with indicating the character set only as a subtype
of text.  One implementor found it useful to have a character set is
non-text objects. A review of the reasons for putting character sets
in a sub-type resulted in no objections to moving this information
into a new header.

I can't help feeling that the Character-set header will mean something 
very particular for type TEXT: in fact it will just be a sub-type.
Whereas whatever uses are found for it for other Content-type/subtypes
will vary in optionality and meaningfulness. I would like to keep the
original TEXT/sub-type format for type TEXT and define a more exact
meaning for the Character-set type.

I suggest that the Character-set header define the set of glyphs which
are necessary to display the body-part. For example:

        Content-type: TEXT/MNEMONIC
        Character-set: ISO8859-1

The receiving mail-reader knows that though TEXT/MNEMONIC defines a very
large number of glyphs, this particular message can be displayed using
only the glyphs from ISO8859-1. This might mean that the message can be
displayed on a fairly dumb terminal, and it also defines what fonts need
to be available in the case where you are displaying on a bitmap terminal.

This also defines a fairly consistent meaning for the Character-set header
for other Content-type/sub-types, though whether it is the intended 
meaning I don't know.

Bob Smart