From: Henry Spencer (henry@spsystems.net)
Date: Sat Mar 16 2002 - 12:52:19 CST
On Fri, 15 Mar 2002, Bruce Lilly wrote:
> I don't believe it is OK to say there is no requirement to support
> RFC 2231; 2231 revises the ABNF of 2045, is a standards-track RFC,
> and is listed in the rfc-index as updating RFC 2045 (among others).
> Any system supporting MIME must therefore support 2231's extensions.
Any system supporting *all* of MIME must support 2231's extensions. There
is nothing wrong with defining a subset.
> As the introductory parts of the draft correctly point out, for a
> considerable time, USENET articles have also been valid text messages
> as defined in RFC 822 (now obsoleted by 2822). Because many clients
> interpret both email and USENET articles using the same code, it is
> highly undesirable that there should be a conflict between RFC 2156
> (or any other RFC which defines a header) and this draft...
Quite so, but the Usenet format (n.b., "Usenet" is not an acronym and
should not be written in all-caps) has always been a *subset* of the mail
format. Even this draft, which liberalizes old practice in a number of
areas, still imposes a number of restrictions. Whether the restriction on
Supersedes is a good idea can be debated, but this particular argument
against it does not hold water.
> Consider also mail-to-news gateways.
Properly-implemented mail-to-news gateways have always had to work fairly
hard to ensure that mail messages conform to the stricter requirements of
news.
> If a header having the functionality of Supersedes is required,
> but with a single msg-id, another header field name should be
> chosen...
No, we simply implement a subset of mail's functionality here, as we do in
a number of other areas. It is still true that tools which are capable of
handling mail messages can handle news articles, so this does not pose any
great problems. (The reverse is not true -- news tools can't necessarily
handle mail messages -- but then, it never *has* been true.)
Henry Spencer
henry@spsystems.net