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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?

Thanks

Ivan

(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
FOAF: http://www.ivan-herman.net/foaf.rdf


Received on Thursday, 19 June 2008 12:43:55 GMT

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