July 2006 - dfdl-wg - lists.ogf.org

RE: [dfdl-wg] DFDL Lite
by Westhead, Martin (Martin) 02 Aug '06

02 Aug '06

One more comment on this Steve suggested that if we were to take this approach we should drive the definition of the subset from a use-case analysis based on some specific formats that we'd take a decision to support. Thanks, Martin _____ From: owner-dfdl-wg(a)ggf.org [mailto:owner-dfdl-wg@ggf.org] On Behalf Of Westhead, Martin (Martin) Sent: Wednesday, July 19, 2006 1:55 PM To: dfdl-wg(a)ggf.org Subject: [dfdl-wg] DFDL Lite Hi Folks, Today's discussion really had me wondering about the size of the thing that we are creating. We are probably looking at a complete spec that is over 200 pages. I feel reasonably strongly that this is too unwieldy. I don't think that we have the editorial resource to effectively bug-check the document and aside from IBM it is difficult to imagine that there are many groups with the resource to implement it. At the end of today's call we started discussing features of XML Schema that we might drop from the first release and my attitude to the discussion was one of resistance. Do we really need to drop attributes? Doesn't the choices document we have pretty much handle wildcards. We are agreed that the property set should be defined with optional libraries around a small, but extensible core. I suggested today that we take the same approach to the whole language. What if were to focus on defining for our initial release a DFDL Lite and look for a minimal set of properties and XML Schema mechanisms that would be useful. Make it as simple and implementable as possible with a minimal of XML Schema and a minimal set of properties. And define it in such a way that we can add the rest of the material as modular supplements (ideally without having to go back and change the existing semantics). There was reasonable support for this approach from those that remained on the call today. I wanted to float it to the group...thoughts anyone? Thanks, Martin

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Notes from telcon 2006-07-26
by Westhead, Martin (Martin) 26 Jul '06

26 Jul '06

Present Mike Beckerle Tom Sugden Bob McGrath Geoff Judd Martin Westhead Steve Hanson Discussion DFDL Lite Various ways of trying to cut down the complexity of the current document were considered. The subset of functionality that IBM considered useful (by considering use-cases) did not succeed in reducing the size of the document very significantly. We talked about the possibility of trying to produce a tighter spec for September just on the basis of limited resources and trying to produce something clear and implementable. How to proceed to refine the current document Mike has an action to review the document and make a list of candidate areas for relegation in this version of the document (note not necessarily the first submitted release) Update on OGF planning We missed the deadline for submissions (because due to the reorg we were dumped off the admin mailing list). We are waiting to see if we can get a scheduled slot.

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DFDL telcon tomorrow
by Westhead, Martin (Martin) 26 Jul '06

26 Jul '06

Time: 9am PDT Number: 1-800-664-0771 At the automated answering system, press 0 for the operator. Ask for the "Daffodil working group" call.

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DFDL Lite
by Westhead, Martin (Martin) 19 Jul '06

19 Jul '06

Hi Folks, Today's discussion really had me wondering about the size of the thing that we are creating. We are probably looking at a complete spec that is over 200 pages. I feel reasonably strongly that this is too unwieldy. I don't think that we have the editorial resource to effectively bug-check the document and aside from IBM it is difficult to imagine that there are many groups with the resource to implement it. At the end of today's call we started discussing features of XML Schema that we might drop from the first release and my attitude to the discussion was one of resistance. Do we really need to drop attributes? Doesn't the choices document we have pretty much handle wildcards. We are agreed that the property set should be defined with optional libraries around a small, but extensible core. I suggested today that we take the same approach to the whole language. What if were to focus on defining for our initial release a DFDL Lite and look for a minimal set of properties and XML Schema mechanisms that would be useful. Make it as simple and implementable as possible with a minimal of XML Schema and a minimal set of properties. And define it in such a way that we can add the rest of the material as modular supplements (ideally without having to go back and change the existing semantics). There was reasonable support for this approach from those that remained on the call today. I wanted to float it to the group...thoughts anyone? Thanks, Martin

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Telcon Notes 2006-07-19
by Westhead, Martin (Martin) 19 Jul '06

19 Jul '06

Present Geoff Judd Mike Beckerle Steve Hanson Suman Bob McGrath Status on combined doc * Revision 5 has all material except variables proposal in * Size of document is a problem - 150 pages and still with blank sections. Plans for OGF in DC * We are aiming to have a draft document ready for submission/presentation to the GGF audience. * It is not clear that we can get a quorum for a face-to-face at the same time so it may make sense to separate the two. * It was suggested that we might be able to make more of teleconference/video-conference facilities, have longer calls and specific tasks particularly as we come to work more directly on a document. * Conclusion - we will seek in-principle approval for a F2F but hold off on planning a date. Status of separators * This is the task of trying to find an elegant way to express the general problem of determining the length of a structure within the data. Martin is looking at ways to capture this but does not yet have a solution that handles all the difficult cases. Tech discussion topics * We had a discussion on the inclusion of attributes. The proposal was that attributes should not be included for direct population but a specific proposal to allow their inclusion in the data model using references should be considered. * DFDL Lite - at the tail end of the meeting after some people had dropped we started considering a different approach to the problem of trimming down the scope - rather than looking for tricky things we could cut off could we look at the simplest DFDL that does something useful and build it so that it can be grown. I will send out a separate email on this topic.

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DFDL Telcon today
by Westhead, Martin (Martin) 19 Jul '06

19 Jul '06

Time: 9am PDT Number: 1-800-664-0771 At the automated answering system, press 0 for the operator. Ask for the "Daffodil working group" call.

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Prototyping Progress
by Tom Sugden 14 Jul '06

14 Jul '06

Hi all, I've been reading draft DFDL spec and scoping doc, and playing around a little with a prototype implementation of an event-based DFDL processor. Unfortunately my time has been limited because the effort has not been scheduled here at EPCC. The general idea is to first generate an internal representation of a DFDL schema. This object model should be easier to work with than a DOM Document and will provide access to the context within scope for each element of the object model, including the supported conversions. For a read scenario, an instance of this object model can be traversed while the underlying data stream is processed into a sequence of DFDL events. At the moment the proto-type supports the example given in section 12.2 of the scoping document. A push-parse is currently implemented, though a pull-parse should also be possible. I'm sorry for regularly missing the telcons. I was away for a while getting married and honeymooning, then got stuck in a meeting on Wednesday. Next week I'm teaching at the grid summer school, but I hope to resume some DFDL work the week after that. Looking forward to seeing developments in the new specification document. Cheers, Tom

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DFDL work group call 2006-07-12
by Mike Beckerle 12 Jul '06

12 Jul '06

Attended: Martin Westhead Mike Beckerle Steve Hanson Status: Mike working on consolidating wildcards/uncertainty, variables, defaults/nulls/optionals, and list of properties into the combined document. Martin sent materials on hidden elements to Mike also for incorporation. So called "missing" materials on selectors/test/guards is actually in the conversions material (will need to be refactored out given current combined doc outline) Goal: all these pieces combined in 1 to 2 weeks. Martin still working on how to express semantics of groups, targeting a write up of something in 1 to 2 weeks. Planning: General GGF meeting in Sept. 11-14, In Washington DC. We will need to present there. However, there's no reason for our GGF presentation sessions to be part of our F2F meeting. Tentative plan: Face to Face workgroup meeting on Sept 13, 14, 15 ? IBM can host at a facility, but these are in the suburbs; hence, are not near the Convention center where Grid World and GGF will be taking place. *** Question for the group: are these dates reasonable? Who would/ would not be able to attend? Our goal should be to have our combined draft document in 'reasonable shape' such that we can use the GGF meeting to invite/recruit new members. What we mean by 'reasonable shape' is not that the document will be anywhere close to final form, but more like the document will be informative and not mislead people about the direction we are heading. We'll have to make a call on whether we think we'll achieve this level with our document about a month in advance of the GGF meeting since we'll need to reach out to potential new members for our WG in advance of the GGF meeting in order to get them to attend the sessions. ...mikeb Mike Beckerle STSM, Architect, Scalable Computing IBM Software Group Information Integration Solutions Westborough, MA 01581 voice and FAX 508-599-7148 home/mobile office 508-915-4795

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Telcon now
by Westhead, Martin (Martin) 12 Jul '06

12 Jul '06

Sorry for the late reminder Time: 9am PDT Number: 1-800-664-0771 At the automated answering system, press 0 for the operator. Ask for the "Daffodil working group" call.

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DFDL scoping version 018
by Mike Beckerle 07 Jul '06

07 Jul '06

I incorporated comments from our WG call and updated the scoping document: https://forge.gridforum.org/sf/docman/do/viewDocument/projects.dfdl-wg/docm… There is no substantive change here. I just put in the TBDs people asked for, fixed a few things where extensibility was being impacted, and fixed typos. ...mikeb Mike Beckerle STSM, Architect, Scalable Computing IBM Software Group Information Integration Solutions Westborough, MA 01581 voice and FAX 508-599-7148 home/mobile office 508-915-4795

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