Re: draft-ietf-impp-cpim-msgfmt syntax

Derek,

Wednesday, November 6, 2002, 12:50:45 PM, you wrote:
Derek> Actually, MsgFmt is a (strict) subset of MIME...  Are you saying that
Derek> a MIME parser could not parse a MsgFmt message?

A.  Perhaps you mean strict subset of RFC 2822?  (The MIME part is not the part
that requires an interesting parser.  It's the body-part -- the content
inside -- that requires it.

B.  There's reading and there is writing.  -msgfmt- sure ain't compatible
with common RFC822/2822 *generation*

B.  As to reading, let's see whether your assessment matches what is stated in -msgfmt-:

-msgfmt-:

[I've only included the interesting stuff]

2.2 Message headers


   o  Processors SHOULD NOT impose any line-length limitations.

[this will break parsing for RFC 2822, 2.1.1]


   o  UTF-8 character encoding [21] MUST be used throughout.

[this will break parsing for RFC 2822, eg 2.1, 2.2, and 2.3]


   o  The header name contains only US-ASCII characters (see later for
      the specific syntax)

   o  The header MUST NOT contain any control characters (0-31).  If a
      header value needs to represent control characters then the escape
      mechanism described below MUST be used.

[These contradict the UTF-8 specification, above.]


   o  Headers names MUST match exactly (i.e. "From:" and "from:" are
      different headers).

[I won't try to research whether this will break 2822.  It does, however,
constitute a very, very basic change to the philosophy of 822/2822.]


   o  Message processors MUST NOT change the order of message headers.

[So does this.]



In other words, profiling another spec, by specifying restrictions on its
semantics -- eg, what headers are allowed or required -- is one thing.
Messing with its syntax is quite another.

As I said, what you have here is a document that has a spiritual relationship to
RFC2822, but is not able to re-use existing generating or interpreting
software. Hence the concerns I raised remain.

d/
-- 
 Dave Crocker  <mailto:[email protected]>
 TribalWise <http://www.tribalwise.com>
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