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Re: ISSUE-126 (Revisit Datatypes): The list of normative datatypes should be revisited

From: Ivan Herman <ivan@w3.org>
Date: Thu, 19 Jun 2008 14:43:16 +0200
Message-ID: <485A5464.9050404@w3.org>
To: Boris Motik <boris.motik@comlab.ox.ac.uk>
CC: 'OWL Working Group WG' <public-owl-wg@w3.org>
Hi Boris,

in case this was discussed on the call, I am sorry because I was not 
there... I would like to understand...

Boris Motik wrote:
> Hello,
> So here is a proposal for resolving this issue.
> 1. We exclude xsd:time, xsd:date, xsd:gYearMonth, xsd:gYear, xsd:gMonthDay, xsd:gDay, xsd:gMonth, and xsd:base64Binary from the list
> of supported datatypes. Note that this doesn't preclude people from implementing them (if they can figure out how to do this).
 > 2. We define xsd:anyURI to be a subset of xsd:string.

Can you elaborate what this means? For example, xsd:date is used quite a 
lot in RDF data using vocabularies like Dublin Core, Bibliography 
Ontology, or others. What does this mean for those data? That they will 
be, sort of 'well-formed' to use an analogy from the XML world, but not 
valid? Or they will be rejected? Or they will be rejected by some tools, 
but not by others?



(These vocabularies use a very shallow level of OWL today, or not at 
all. But I would expect, that, on long term, they might evolve  in 
taking up more and more OWL features. At least we should not create 
obstacles in them doing so.)

> 3. We allow the "pattern" facet only on the following datatypes: xsd:string, xsd:anyURI, xsd:normalizedString, xsd:token,
> xsd:language, xsd:NMTOKEN, xsd:Name, and xsd:NCName.
> 4. We introduce a new owl:real datatype. This datatype would allow for the following types of constants:
> - rational numbers written according to http://www.w3.org/2007/OWL/wiki/OWL_Rational
> - floating point numbers written in the format as specified in the definition of xsd:float and xsd:double in the XML Schema
> - decimal numbers as written in the format as specified in the definition of xsd:decimal
> - integer numbers as written in the format as specified in the definition of xsd:integer and related datatypes
> Furthermore, we would make xsd:float and xsd:double (and possibly xsd:decimal as well) synonyms for xsd:real. This would be the only
> definition from the XML Schema datatype system: there, some very large numbers are not members of xsd:float. I believe, though, that
> this would bother people in practice.
> Finally, we can include xsd:nonPositiveInteger, xsd:negativeInteger, xsd:long, xsd:int, xsd:short, xsd:byte, xsd:nonNegativeInteger,
> xsd:unsignedLong, xsd:unsignedInt, xsd:unsignedShort, xsd:unsignedByte, and xsd:positiveInteger with the existing semantics as
> usual.
> Regards,
> 	Boris


Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
PGP Key: http://www.ivan-herman.net/pgpkey.html
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Received on Thursday, 19 June 2008 12:43:55 UTC

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