Re: MIME implementation documentation

[John C Klensin <[e-mail]>]

On Thu, 15 Aug 1996 23:01:25 -0700  Dave Crocker 
<[e-mail]> wrote:
> 	Yes, we need to audit functions not implemented and remove them
> from the spec.  do you have any candidates for removal?

Just a hunch, based on MUAs I've looked at recently, but
   multipart/alternative
and
   multipart/parallel
are good starters.  The only creation-implementations I know of 
either require either hand-fussing (e.g., editing 
proto-outgoing-messages from /mixed) or specialized assembly 
macros that are not what we normally consider MUAs (e.g., the 
process used to prepare the I-D announcements).

The difficulty I'm having here is that I consider at least one 
of these to be a very valuable and important feature (which 
makes the question Harald asks about what we do about the stuff 
that we "remove" very important), but I wonder if we really have 
the implementations.  Parallel is even worse, because I've been 
involved in several conversations (and imagine others have too) 
that question whether it really is the right design and contains 
the right information to permit a sender to convey adequate 
information to a receiver to make the thing useful.  And we find 
that out only by implementing the thing and getting it out there 
widely enough to accumulate some serious operational experience.

The problem here, obviously, is that coming up with an 
implementation of these things in the sense of some prototype- 
or demonstration-quality critter that can demonstrate the 
ability to put the right format out on the wire and then read it 
from the wire is trivial and uninteresting.  Implementing to a 
level of quality needed to show actual utility -- that the 
feature has the right syntax and semantics to actually serve 
useful purpose as defined -- is, IMO, another matter and I'm not 
convinced that we are there yet.

    john