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RE: P3P Data Schema as XML Schema

From: Massimo Marchiori <massimo@w3.org>
Date: Tue, 29 Apr 2003 18:54:24 +0200
To: "Giles Hogben" <giles.hogben@jrc.it>, "Joseph Reagle" <reagle@w3.org>
Cc: <public-p3p-spec@w3.org>, "Rigo Wenning" <rigo@w3.org>, "Jeremy Epling" <jepling@windows.microsoft.com>

P3Pers, apologies for having missed the call today, XQuery is swamping me these days.
Anyway, some quick words on the "P3P data schema in XML Schema".
This issue had already been tackled quite some time ago in the P3P spec group (you might have wondered if somebody hadn't thought
about it before... right? ;)
In fact, this has at a time been discussed as an alternate proposal, and finally rejected.
I'll state the reasons and some comments here, because these still apply (which means, reopening this issue in P3P1.1 should then
again mean challenge again the "con" of the solution).

First big motivation: who needs it? What are the real advantages? Implementers, at the time, let us know they didn't like the
"xml-schema way" (let's call it this way), because
a) it makes parsing heavier
b) it makes simple data declaration too verbose (as you have to duplicate each subpart of a data element in begin and end tags)

This was the main objection at the time. Now, we are no more in the designing phase (1.0), so tackling this issue again in 1.1 has
to face the new, crucial, additional problem:
c) what are the costs of adding an alternate format to the spec?

There was also other considerations that led not to consider that design, that I'll recap here too:
d) splitting data elements (etc) in separate tags, apparently leads to the loss of the "reference with a URI" property: you'd still
need to recombine the info in a single-line canonicalization to get this property back (so, essentially going back to the status
e) makes DTD support more difficult

Ok, enough with historical motivations for today ;)
So all in all, the above considerations just apply if this proposal is going to end in 1.1 (i.e., it's reopening the issue).
If it's instead a translation-only thing (like the RDFization note of P3P), likely to end as a Note or so, then of course all the
above is moot ;)

> -----Original Message-----
> From: public-p3p-spec-request@w3.org
> [mailto:public-p3p-spec-request@w3.org]On Behalf Of Giles Hogben
> Sent: Tuesday, April 29, 2003 6:28 PM
> To: Joseph Reagle
> Cc: public-p3p-spec@w3.org; Rigo Wenning; Jeremy Epling
> Subject: RE: P3P Data Schema as XML Schema
> Here are some more files on this issue
> I have corrected some small errors in the schema transform (e.g. it was
> outputting category element and attribute element definitions with global
> scope where it shouldn't have been).
> I have also included a 2 stage transform which avoids using extensions (you
> do transform 1 and then transform2 on the results of transform1 to eliminate
> duplicates) and, for the benefit of other members of list the files for the
> policy transform I sent earlier.
> Apologies for confusing the acronyms BDS and BSD... BDS means the base data
> schema and BSD is an OS...
> For those who don't want to get bogged down in nasty amounts of complexity,
> just look at the file bdsfinal.xsd which is the final result schema, or try
> the policy transformer on a policy (e.g. the one included). Hope the
> directory and file names are relatively self explanatory
> Regards
> Giles
> -----Original Message-----
> From: Joseph Reagle [mailto:reagle@w3.org]
> Sent: 28 April 2003 20:08
> To: Giles Hogben
> Subject: Re: P3P Data Schema as XML Schema
> On Saturday 26 April 2003 09:06, you wrote:
> > Yeah - sorry - it was the quickest and easiest way to get it to work
> > at the time - will try to send a self executing .jar file at some
> > point - maybe that'll help.
> I'm still not following, keep in mind I know nothing about MS IE and very
> little about Java (I'm more of a XML and Python person) <smile/>. I was
> expecting to do something like:
>   xsltproc bsdtransform.xsl p3p1_0.xml > converted_p3p_1_0.xsd
> then I can check a P3P instance against that schema:
>   xsv p3p.xml converted_p3p_1_0.xsd
> What is "BSD" btw?
Received on Tuesday, 29 April 2003 12:55:24 UTC

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