From: Bruce Lilly (blilly@erols.com)
Date: Sun Jun 08 2003 - 18:55:33 CDT
Charles Lindsey wrote:
> The Subject-header contains a short string identifying the topic of
> the message. This is an inheritable header (4.2.5.2), normally to be
> copied into the Subject-header of any followup.
>
> header =/ Subject-header
> Subject-header = "Subject" ":" SP Subject-content
> Subject-content = unstructured
>
> NOTE: The syntax of unstructured differs from that prescribed in
> [RFC 2822], so ensuring that the Subject-content is not
> permitted to be completely empty, or to consist of WSP only (see
> remarks in 4.2.6 concerning undesirable headers).
I again request that as reference is made to RFC 2822, where terms used
in 2822 are used in this draft with a different meaning and a different
definition (and often different semantics), that a different name be used
to minimize confusion. In this case, something other than "unstructured";
use "usefor-unstructured" if you like, or "frammis" -- anything that doesn't
have a specific different meaning in RFC 2822 (or 2045, etc. where applicable).
> Followup agents MAY (and usually will) prepend the back-reference
> "Re: " (which is case sensitive) to the Subject-content of the
> precursor when preparing the followup (unless that precursor is
> itself a followup with "Re: " already present in its Subject-
> content).
According to RFC 2822 semantics and syntax, what is really being prepended
is " Re:" rather than "Re: ", because the field body of the field
Subject: foo
begins with a space character.
For consistency, it may be best to move the SP from Subject-header
to Subject-content and revise "Re: " to " Re:".
> Followup agents MUST NOT use any other string except "Re: " as a
> back-reference, and specifically NOT a translation of "Re: " into a
> local language, and they MUST NOT prepend a "Re: " if one is already
> present.
MUST NOT is too strong in both instances in the above text, since the
issue does not meet the requirements for use of MUST NOT given in RFC
2119 section 6. Aside from that, there are UAs that under some circumstances
will perform other transformations on the original subject field body.