Re: P3P and XML Schemas

I believe that in this respect we are at least as expressive as DTDs.  In 
other words, schemas can model:

        (A|B|C)*

We additionally provide the equivalent of:

        ( (A?) & (B)  &(C?) &(D))

In other words, a B and a D, with optional A and C, all in any order.  So 
we are already better than DTD.  We cannot do:

        ((A*) & (B) & (C?)) & (D))

which I believe is being requested.  I think it's reasonable that we 
consider this, but I think we should reserve the right to decline.  There 
are lots of 80/20 points in all this, and we are already better than DTD, 
I think.  What about:

        <all> <any namespace="XXX"/> </all>

(Any number of elements from namespace XXX, all in any order, and at most 
once.)  Very useful, especially as a base class, but also not supported. 
We have to draw the line somewhere.

------------------------------------------------------------------------
Noah Mendelsohn                                    Voice: 1-617-693-4036
Lotus Development Corp.                            Fax: 1-617-693-8676
One Rogers Street
Cambridge, MA 02142
------------------------------------------------------------------------







ht@cogsci.ed.ac.uk (Henry S. Thompson)
Sent by: www-xml-schema-comments-request@w3.org
04/07/00 04:13 AM

 
        To:     "Martin J. Duerst" <duerst@w3.org>
        cc:     www-p3p-public-comments@w3.org, www-xml-schema-comments@w3.org, (bcc: Noah 
Mendelsohn/CAM/Lotus)
        Subject:        Re: P3P and XML Schemas

"Martin J. Duerst" <duerst@w3.org> writes:

> Sorry, my original mail had one of the addresses wrong,
> I hope this is corrected now.

> [discussion elided]

> On the XML schema side, if it's currently not possible to express
> arbitrary order with occurrence constraints, that may be a problem
> independent of whether P3P needs it; I'm sure there are other uses
> where this is a requirement.

> At 00/04/04 22:12 +0100, Henry S. Thompson wrote:

> >[other stuff]
> >
> >If what you want is arbitrary order, just what do you mean by that,
> >e.g. , is the following OK?
> >
> >  <extension>...</extension>
> >  <statement>...</statement>
> >  <disclosure>...</disclosure>
> >  <statement>...</statement>
> >  <extension>...</extension>
> >  <statement>...</statement>

The above question is pressing, if you want the WG to consider
"arbitrary order with occurrence constraints", we really need clear
input on this.

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of 
Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
                     Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
                                      URL: http://www.ltg.ed.ac.uk/~ht/

Received on Monday, 10 April 2000 21:14:13 UTC