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RE: ISSUE-95 (Datatype-facet compatibility in DatatypeRestriction): No compatibility restrictions between the datatype being restricted and the facets in the DatatypeRestriction construct

From: Boris Motik <boris.motik@comlab.ox.ac.uk>
Date: Wed, 20 Feb 2008 19:31:11 -0000
To: "'OWL Working Group WG'" <public-owl-wg@w3.org>
Message-ID: <015f01c873f7$2642d690$7212a8c0@wolf>
Hello,

 

As decided at today's teleconference, I have updated the spec to allow datatype restrictions to be stated only on datatypes. Here is
a diff:

 

http://www.w3.org/2007/OWL/wiki/index.php?title=Syntax <http://www.w3.org/2007/OWL/wiki/index.php?title=Syntax&diff=3435&oldid=3313>
&diff=3435&oldid=3313

 

I've also updated Figure 5.

 

Unless someone objects, I believe that we can close this issue at our next meeting.

 

Regards,

 

            Boris

 

  _____  

From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org] On Behalf Of Boris Motik
Sent: 13 February 2008 19:55
To: 'OWL Working Group WG'
Subject: RE: ISSUE-95 (Datatype-facet compatibility in DatatypeRestriction): No compatibility restrictions between the datatype
being restricted and the facets in the DatatypeRestriction construct

 

Hello,

 

ISSUE-95 did not get resolved today because many people agreed that the current solution is just broken. In the e-mail I sent out on
Sunday (please see below), I think this issue can be resolved really easily by simply making Datatyperestriction take a Datatype as
an argument instead of a DataRange. I can implement this solution in 5 minutes, we can resolve the issue next week, and we can be
happy for making some progress.

 

I have heard some concerns that we should delay resolving this issue until the proposal for n-ary datatypes is ready. I do not see,
however, how this issue is related to n-ary datatypes. Clearly, when the n-ary datatypes are introduced, they can define their own
facets and extend the facet table compatibility. I do not see why this future extension should hinder closing the current issue in a
clean manner.

 

Could I ask people who are not in favor of my proposed solution to present their case?

 

Regards,

 

      Boris

 

> -----Original Message-----

> From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org] On Behalf Of Boris Motik

> Sent: 10 February 2008 20:11

> To: 'OWL Working Group WG'

> Subject: RE: ISSUE-95 (Datatype-facet compatibility in DatatypeRestriction): No compatibility

> restrictions between the datatype being restricted and the facets in the DatatypeRestriction

> construct

> 

> 

> Hello,

> 

> I've just added a table to the structural specification that lists the compatibility between

> datatypes and facets. Here is a diff

> URL:

> 

> http://www.w3.org/2007/OWL/wiki/index.php?title=Syntax&diff=3312&oldid=3311

> 

> 

> To close ISSUE-95, we need to sort out the problem of what the restriction is being applied on. Since

> we all basically agree that

> nesting restrictions is either unclear from a semantic point of view (such as putting minInclusive on

> not(Integer)) or that nested

> restrictions can be flattened (such as putting a datatype restriction on another datatype

> restriction), I propose to keep the

> specification simple and to disallow nesting.

> 

> Regards,

> 

>     Boris

> 

> > -----Original Message-----

> > From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org] On Behalf Of OWL Working

> > Group Issue Tracker

> > Sent: 20 January 2008 12:55

> > To: public-owl-wg@w3.org

> > Subject: ISSUE-95 (Datatype-facet compatibility in DatatypeRestriction): No compatibility

> > restrictions between the datatype being restricted and the facets in the DatatypeRestriction

> > construct

> >

> >

> >

> > ISSUE-95 (Datatype-facet compatibility in DatatypeRestriction): No compatibility restrictions

> between

> > the datatype being restricted and the facets in the DatatypeRestriction construct

> >

> > http://www.w3.org/2007/OWL/tracker/issues/

> >

> > Raised by: Boris Motik

> > On product:

> >

> > Hello,

> >

> > I believe that we have a slight problem with the DatatypeRestriction.

> >

> > 1. Problem

> > ----------

> >

> > Currently, the DatatypeRestriction construct takes one dataRange and several facet-value pairs.

> Note

> > two important points here:

> >

> > - The data range can be complex.

> > - There are no compatibility restrictions between the data range and the facets.

> >

> > The first point makes it possible to write DatatypeRestriction(

> > DataComplementOf(xsd:nonnegativeInteger) fractionDigits "2"^^xsd:integer). It is unclear how to

> > interpret this datatype. The complement of xsd:nonnegativeInteger contains all data values that are

> > not nonnegative integers, which includes, say, real numbers, but also includes all strings. It is

> > unclear what restricting such a datatype to 2 precision digits means. Originally, a dataRange was

> > used because this allowed one to specify, say, minInclusice and maxIncludive via nesting; with

> > mutliple facets per DatatypeRestriction this is not necessary any more.

> >

> >

> > The second point makes it possible to write DatatypeRestriction(xsd:string fractionDigits

> > "2"^^xsd:integer). Again, it is unclear whether this is a syntax error or, if not, how to interpret

> > this datatype.

> >

> > 2. Possible solution

> > --------------------

> >

> > A possible solution would be to change the definition of DatatypeRestriction in the following way:

> >

> > - Rather than taking a dataRange as an argument, we should make DatatypeRestriction take a Datatype

> > as an argument.

> > - We should specify compatibility between different datatypes and factes. For example, we would say

> > that fractionDigits could be applied only to the xsd:float datatype.

> >

> > This solution seems to be in line with the XML Schema way of handling things: if I am not mistaken,

> > in XML Schema one cannot apply an arbitrary facet to an arbitrary datatype.

> >

> > Regards,

> >

> >   Boris

> >

> >

> >

> 

> 

 
Received on Wednesday, 20 February 2008 19:32:10 GMT

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