See http://forge.gridforum.org/docman2/ViewCategory.php?group_id=113&category_id=803&language_id=1&sort0=ddate&dir0=1
The document is "DFDL Proposal"
and is posted in word and pdf formats. If you use the above URL it should
be the top 2 documents on your display.
We made the official deadline which
means I can really needle people to study this document and comment on
it on or before GGF15.
A couple of notes: My group at IBM produced
this draft. While we tried to fold in the viewpoints of others at IBM that
we have been working with over the past few months, I cannot represent
that this document reflects any overall consolidated "IBM opinion"
on DFDL at this time. There hasn't been time for the rounds of IBM-internal
review that would require. Rather this is my group's take on things.
It reflects our best shot at how to combine the concepts of the OMG TD
model and its attributes with the rest of the DFDL concepts. We updated
the scoping proposal to fix some ambiguities left over from the F2F last
may, and there's a section on layering which only starts to tell the story
about this powerful capability, but is a good start at it. There's a middle
section which just gets started at the agenda of explaining all the subtlety
of exactly how delimiting and tagging work, and how lengths and positions
are determined and so forth.
You'll see lots of TBDs and rationale
discussion in here still. My goal is that by or at GGF15 we resolve many
of these so these rationale blocks can move down into the appendices or
into separate documents, allowing us to focus on the meat of specifying
the core behavior more thoroughly.
In the appendix which contains the rep-properties
detail you'll see lots of conflicts. E.g., we have byteOrder=bigEndian/littleEndian
AND we have bigEndian=true/false. This is intentional and is the
remnants of joining forces with the OMG Type-descriptor model. We need
to decide on these conflicts i.e., for each one, which way do we want to
go. There are quite a few such conflicts to be resolved.
Our prototype implementation does not
implement exactly what is described in this draft, though it is quite close.
The differences are fairly insignificant.
I recommend grabbing the MSWord version,
and inserting lots of comment blocks as you read it using the comments
feature. It is a big document though (50 pages), and different parts of
it are more accessible than others, so do what you will.
Mike Beckerle
Architect, Scalable Computing
IBM Software Group
Information Integration Solutions
Westborough, MA