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   RE: [xml-dev] Annotations in XPath-NG? (Re: [xml-dev] XPath/XSLT 2.0 co

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Jeni Wrote:
> Uche wrote:
> Kieth had written:
> >> This is actually something similar to what I intend to implement
> >> over an XML Repository [probably Xindice].
> >> 
> >> We have a requirement to be able to; given a node, find all
> >> annotations [of a particular type or matching certain criteria], on
> >> that node.
> >> 
> >> While I want to be able to express this as an Axis in the XPath
> >> object model, I've got a few problems with that:
> >>
> >> 1. How do I specify the Annotation context for the annotation axis.
> >> Our annotations are stored as standoff annotations, and to
> >> complicate things further, may apply to either a single document or
> >> a collection of documents.
> Keith: Do you mean how do you get *back* from an annotation to the
> node from which you got it? That's a different problem, I think -- I
> don't think that for every axis there must necessarily be an axis that
> takes you in the reverse direction.
No, thats not what I mean.  In my system, the annotations point [via
XLink-like HREF] to the nodes they annotate.
> >> 2. It's a heck of a lot easier to create a new XPath function in
> >> existing public domain XPath implementations than it is to change
> >> the parsing and execution model.
> >
> > This is very true, and another key reason with my uneasiness with
> > extension axes.
> But this is why I'd like to see XPath-NG defined differently. Rather
> than listing all the possible axes, you'd have:
>   AxisName ::= QName
> and then it would be up to separate modules to specify useful axes for
> that module.
> I can certainly understand the reluctance to go with axes if you're
> working without the boundaries of XPath 1.0, but if we're reaching for
> XPath-NG then why not?
Mostly commercial reasons, I still like the annotation axes better, but just
don't see a way to make it fly in my projects time frame.  Usually, I can
use leading edge, but not bleeding edge components.  On the other hand, if I
see something bleeding edge that can be vetted against leading edge
components without a great deal of cost, then I can probably use it.

> I'd prefer them to be elements identified by name. For example:
>   <psvi:type-definition>xs:integer</psvi:type-definition>
>   <xforms:required>true</xforms:required>

How is the annotation linked to what it annotates in your examples?

> Hmm... Do you think that it's too loose to leave it up to the
> particular annotation to determine what other structure might be
> defined around the element node that's returned through this function?
> It would be useful if you could use an annotation that gives you a
> hook into the PSVI as a starting off point for navigating the PSVI,
> for example. Or an annotation might be standalone, in its own document
> for all intents and purposes. What matters is that the annotation
> function/axis returns a bunch of element nodes -- I don't think that
> we really need to care where they come from.

Actually, I am somewhat interested in where they came from.  In our library
of medical records, we have annotations on sentences attesting to codes that
are justified by that sentence.  I would want to identify the source of the
code [one of several software modules, human review, et cetera].  That's
actually not terribly difficult.  If I can get to the element, then I can
get to it's parent or ancestor which could tell me that information.

<<attachment: winmail.dat>>


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