MIME and HTML/SGML

Daniel Glazman (Daniel.Glazman@der.edf.fr)
Mon, 3 Apr 95 08:53:26 EDT

The recent postings about charsets and MIME/SGML conflicts
reflect two very different opinions. I guess a clarification
on this point from a MIME *and* SGML developer is
not uninteresting...

MIME, originally designed for SMTP messages only, is used for
message structuration. Extensions define the TYPE of a message
or one of its bodyparts. I insist on the global meaning of TYPE.
TYPE has no capacity at all to define the CONTENT itself directly.
This significant but slight difference can be shown as follows:

* a MIME message contains information about the TYPE
of its bodypart
* the local mailcap file contains information about the
CONTENT of a bodypart given the bodypart's TYPE.
* MIME attributes (charset for instance) can be passed
as an argument to the composing tool

Let's be more precise: if MIME defines two Kanji charsets for
instance, fully compatible without order (I mean: mapping
possible but not immediate), MIME can compose a message containing
a Kanji text written using the first charset and composed using
the second charset. No problem if the mailcap file's entry for
this type contains a filter in its composing command...
Many of us already use a such mechanism for audio postings;
the composing line may be written as follows:

audiorecord | audioconvert -f %t > %s

So what ?

A SGML document, written in a given charset, can easily be sent
through a MIME message in a compound/sgml (Gosh ! What is the
current name of the SGML multipart in last draft ?) if the composing
command ("compose" and "composetyped" lines in mailcap file) runs
through/uses a SGML parser...

A SGML parser is able to extract from an instance its charset and
return it to the UA/Daemon through the "composetyped" entry.

I can't see there any conflict at all between SGML/HTML and MIME.

It is just another point pleading on SGML parsers' integration
behalf...

</Daniel>
PS: such a posting may generate flames from other MIME developers...
but I am sure that it is a defensible position.