Keith Moore wrote:
MDNs and DSNs are rather unusual MIME multipart messages. The fields
(N.B. they are described as fields in those RFCs) are in fact defined
using RFC 822 syntax (both RFCs predate RFC 2822):
no, they are defined using ABNF notation, which is not the same thing.
Distinction noted, but that doesn't clarify matters. 1894 also states:
Since these fields are defined according to the rules of RFC 822, the
same conventions for continuation lines and comments apply.
Notification fields may be continued onto multiple lines by beginning
each additional line with a SPACE or HTAB. Text which appears in
parentheses is considered a comment and not part of the contents of
that notification field. Field names are case-insensitive, so the
names of notification fields may be spelled in any combination of
upper and lower case letters. Comments in DSN fields may use the
"encoded-word" construct defined in [7].
Reference 7 is RFC 1522, an earlier part of the MIME RFCs (the current
set includes 2047, which is the part dealing with encoded words).
As author of 3 of the 4 DSN RFCs I can confidently state that
the structuring conventions of RFC 822 header fields were not intended
to apply to DSNs fields.
In light of the above quote from section 2.1.1 of RFC 1894, could you
please clarify which parts of 822 header fields structuring conventions
do not apply to the DSN fields; certainly the ABNF is used, and 2.1.1
refers to continuation lines and comments. Perhaps whitespace may not
be freely inserted between lexical tokens? From a practical point of
view in parsing header fields and parsing DSN fields, what are the
substantive differences?
> And as author of RFC 2047 I can confidently
state that encoded-words are not intended to be used or interpreted in
message bodies (except for message bodies that by their definition
contain 822 messages or message headers)
That would seem to be a repudiation of 1894's reference to 1522
specifically mentioning encoded-words. It seems that I must be
missing something terribly important or there's a contradiction
between what you and G.V. wrote in 1894 section 2.1.1 and what you
now say w.r.t. encoded words and DSN fields -- have I misunderstood?