Minutes for XProc WG telcon of 19 Jan 2006

See http://www.w3.org/XML/XProc/2006/01/19-minutes.html

                                   - DRAFT -

                            XML Processing Model WG

19 Jan 2005


   See also: IRC log[3]


           Norm, Rui, Alessandro, Henry, Paul, Andrew, Richard, Alex, Erik



           Norman Walsh


     * Topics
         1. Administrivia
         2. accept this agenda?
         3. accept minutes from the previous teleconference?
         4. next meeting: 26 Jan 2006.
         5. Tech Plenary
         6. Requirements and Use Cases
         7. Any other business
     * Summary of Action Items




   <scribe> Scribe: Norman Walsh

   <scribe> ScribeNick: Norm

   Date: 19 Jan 2005


  accept this agenda?

   -> http://www.w3.org/XML/XProc/2006/01/19-agenda.html[4]


  accept minutes from the previous teleconference?

   -> http://www.w3.org/XML/XProc/2006/01/12-minutes.html[5]


  next meeting: 26 Jan 2006.

   Any regrets?

   Possible regrets from Norm

   Henry to chair in Norm's absence

  Tech Plenary

   Registration is now open; discounted rates at the Sofitel end tomorrow

  Requirements and Use Cases

   Thank you, Alex

   Alex: Some consolidation needed on the use cases; they aren't tightly
   coupled with the requirements yet
   ... Many use cases contain the same components.
   ... It might be a good idea to factor out the common bits

   Norm: Was lack of discussion about PSVI in "Infoset Processing"

   Alex: It does say augment...

   Norm suggests "Infoset, augmented infoset, or other data models"

   Erik: Is there agreement already that the infoset is our minimum?

   Alex: From an XML perspective, that seems right

   Norm: Erik, did you have something else in mind?

   Erik: No, that's fine

   Alex: Augmenting or annotation infosets is something I've always imagined
   a pipeline language could support

   Norm points out some ways that XDM is different from Infoset.

   Erik: can you consider the XDM as a superset of the Infoset?

   Richard: It's not a subset or superset but it has a correspondence

   Some discussion of XDM follows.

   Richard: I'm worried that we're trying to include too many things. We
   should concentrate first and formost on infosets and anything else should
   be an extension

   Erik: I'm inclined to agree, but we have also had mail that suggests we
   need to support some things that aren't infosets (documents containing
   only text nodes, etc.)
   ... The best place to look if we need to do those things may be XDM.
   ... Rather than specifying our own thing, we should point to XDM.
   ... This might also make it easier to deal with parameters as they could
   be the XDM instances from some previous process

   Alex: I can see the advantage of XDM, but there are lots of simple
   pipelines that don't require that

   Richard: I assume at this stage we aren't planning to standardize the
   representation of XDM. One way to do this is to say that you pass infosets
   or extended infosets and anything you want to pass like XDMs, you
   represent them as extended infosets

   Norm: that appeals to me

   <alexmilowski> How about: "At minimum, an XML document is represented and
   manipulated as an information set. Use of a super-set, augmented or
   extended information sets, or data models that map to information set
   should be allow be implementations."

   Erik: this is a minimal goal; we may come back to this later

   Richard: I think that saying things like XDM are represented as extended
   infosets at least gives us a handle on what kinds of things can be in
   ... I'd like to say that what passes between components are infosets,
   possibly augmented

   Erik: I think one thing we are trying to say is that this is a minimum
   requirement. The model must support passing infosets between components.
   If an implementation wants to say that it supports passing things from
   XDM, maybe we should try to allow this.

   Richard: I did not intend to allow you to pass a sequence of integers
   between components
   ... I want extensions such as that to be outside the scope of what we are

   Erik: XDM is an XML Data Model and it does allow more things

   <Zakim> MSM, you wanted to express uneasiness about the phrase
   "represented as" followed by the phrase "an infoset". Infosets are way too
   abstract to serve as representations in any

   MSM: Richard made me very nervous by speaking about data models
   "represented as" infosets. It suggests that infosets are APIs or data
   structures and I think they are neither. They are more abstract.

   Richard: I understand your reservation and I agree essentially.
   ... I certainly wasn't implying anything about an API; I simply wanted to
   constrain things sufficiently such that we could speak of passing
   information items around rather than talking about integers and sequences.

   MSM: I think that can be paraphrased as "data models conceptualized as
   infosets" and I'm happy with that.

   <richard> i am happy with "conceptualized as" rather than "represented as"

   Norm: Any other concerns about design principles?

   Moving on to terminology...

   Alex: I tried to factor out the the distinction between straight-through
   processing as pipelines and process models which may be more complex.
   ... Those are both really the subject of our spec.

   Henry: I don't find this helpful. It's useful to get started on iterating
   over this.
   ... I don't think restricting pipeline to "straight through" is very clear
   or likely to work for this group.
   ... I agree the distinction is important, but I'd rather not do it this

   Richard: I partly agree with Henry because I think "process model" is
   probably interpreted as a more general term and includes descriptions of
   how they are processed that doesn't include things that we're going to

   Norm: I concur

   Alex: Maybe we could define one and then I could take a pass through to
   use that term consistently.

   Norm: I think of the pipeline as the whole thing

   <ht> HST likes 'XML Pipeline' for the whole space, 'pipeline language' for
   AM's 'specification language' and 'pipeline document' for an XML document
   in a pipeline language

   Richard: I see pipeline conceptually as the flow of a document through a
   series of components. They aren't linear.

   Erik: If we do use the term "pipeline", I'd like that to mean the whole

   <ht> +1 -- A pipeline is a configuration of steps, steps involve
   components and connectivity and parameters

   Henry: I like "pipeline" for the whole thing that documents pass through,
   I like "pipeline document" to describe a document in a "pipeline
   language". Pipelines have "steps" which consist of "a component" plus it's
   parameters and connectivity.

   Alex: I don't like the term "process model". So I'm happy to consolidate
   these things into "pipeline"

   Richard: A step can be used in isolation, but when you specify what a unix
   program does, you specify what it's standard input/output/error and
   parameters are and that seems to be consistent with "component"

   Erik: A component could be XSLT or XQuery, but a step is an instance of
   one of those things.

   Richard: I agree that a step is an instance of a component with various
   things associated with it.

   Erik: "Step" has a strongly linear connotation, but we might have things
   in parallel or conditional.

   Richard: Yes, but it is used in descriptions of programming languages and
   that covers the parallel case for me.

   Alex: Maybe we can take a stab at defining "pipeline" and "step" to
   replace process model.

   Alex proposed something the scribe failed to capture

   <alexmilowski> A pipeline is a configuration of steps that defines, but
   not limited to, order, dependencies, or iteration along with their

   Norm asks about the term "component vocabulary"

   Some discussion follows

   <ebruchez> We've used the term "interface" to describe how a component
   communicates with the rest of the pipeline

   Alex: when I say vocabulary, I actually mean an XML language (a set of XML

   Richard: I think what Erik described as an interface is what I described
   as a "component specification": the thing that a generic pipeline editor
   would need to have
   ... to allow you to join components together

   Alex: maybe we could consolidate "use environment" and "binding"?
   ... there's a whole context in which a pipeline runs.

   Richard: I think "environment" is quite widely used. Binding seems more

   Alex: Maybe we could use "pipeline environment"

   Norm: Yes.

   Alex: I suggest that people send feedback by email. The two most critical
   bits are: which things should be combined or refactored and the
   connections between requirements and use cases.

   <richard> The great thing about the term "pipeline" is the associated
   plumbing metaphor - sources, sinks, the ability to insert Ts and so on

   Alex: I'll shoot for another draft on Tuesday.

  Any other business

   If you're going to be at the f2f, please describe your conflicts for
   Monday/Tuesday by email.

   If you're not going to the f2f, please indicate if you'd like to dail in
   for all or part of our meetings. Taking into account the time of day in
   your part of the world :-)


                                        Be seeing you,

Norman.Walsh@Sun.COM / XML Standards Architect / Sun Microsystems, Inc.
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Received on Thursday, 19 January 2006 17:11:16 UTC