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Re: APPEL and the dataschema element

From: Giles Hogben <giles.hogben@jrc.it>
Date: Mon, 1 Oct 2001 18:29:48 +0200
Message-ID: <00b501c14a96$49dcee10$162abf8b@pcdsa22>
To: "Nikolaj Budzyn" <budzyn@ti.informatik.uni-kiel.de>, "Lorrie Cranor" <lorrie@research.att.com>, <www-p3p-dev@w3.org>
See comments:


> > > But this seems to cause a serious problem for the APPEL matching
algorithm
> > >
> > > Here is an example of what I mean:
> > >
> > > RULESET
> > > ========
> > >  <DATA-GROUP base="mycustomschema.xml" appel:connective="or">
> > >         <DATA category="online"/>
> > >       </DATA-GROUP>
> > >
> > > EVIDENCE
> > > ========
> > > <DATA-GROUP base="" appel:connective="or">
>
> Oops? There can't be an appel:connective in the *evidence*!

sorry! Copy and paste error

>
> base="" would mean the local document, the policy, f.e.
> I guess, you just mean <DATA-GROUP>?

No, I think I meant <DATA-GROUP base=""> because the problem is precisely
with embedded schemas - because they are now embedded above the policy
level, and so can't be expressed in APPEL.


>
> > >         <DATA ref="#user.home.online.email"/>
> > >         <DATA ref="#user.home.online.uri"/>
> > >         <DATA ref="#user.business.online.email"/>
> > >         <DATA ref="#user.business.online.uri"/>
> > >         <DATA ref="#dynamic.cookies" category="online"/>
> > >         <DATA ref="#dynamic.miscdata" category="online"/>
> > >       </DATA-GROUP>
> > >
> > >
> > > Although the ruleset and the evidence may be referring to the same
> > external
> > > schema, the matching algorithm ( APPEL 5.5.2 ) will fail on the
> > <DATA-GROUP>
> > > element.
>
> That's right. So the matching semantics of the <DATA-GROUP> and the
> <DATA> element will be changed slightly in the upcoming spec:
> Each DATA ref attribute needs to be expanded to a full URI with respect to
> the DATA-GROUP base attribute, if any. The DATA-GROUP ref attribute
> will not be matched directly any longer.

Does this mean an expansion is made on the policy element? Could you make
this a little clearer.
Specifically as to how it will solve the problem of the path to an inline
schema ("") (which now can't be expressed in APPEL) and the path to an
external schema being different:

It seems to me that what you have just said still leaves a problem.

Take the previous example:

RULESET
========
 <DATA-GROUP base="mycustomschema.xml" appel:connective="or">
        <DATA category="online"/>
      </DATA-GROUP>

EVIDENCE
========
<DATA-GROUP base="">
                <DATA ref="#x.y.z"/>
        <DATA ref="#x.y.w"/>
        <DATA ref="#a.b.c"/>
        <DATA ref="#a.b.e"/>
      </DATA-GROUP>


After expansion on both sides would then be

RULESET
========
 <DATA-GROUP  appel:connective="or">
         <DATA ref="mycustomschema.xml#x.y.z"/>
        <DATA ref="mycustomschema.xml#x.y.w"/>
        <DATA ref="mycustomschema.xml#a.b.c"/>
        <DATA ref="mycustomschema.xml#a.b.e"/>
etc. . . .
      </DATA-GROUP>

EVIDENCE
========
<DATA-GROUP  appel:connective="or">
             <DATA ref="#x.y.z"/>
        <DATA ref="#x.y.w"/>
        <DATA ref="#a.b.c"/>
        <DATA ref="#a.b.e"/>
      </DATA-GROUP>


This still seems to produce a matching failure:

Could you give me an idea of when are we likely to see the new
specification?

Thanks

Giles
Received on Monday, 1 October 2001 12:29:01 GMT

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