- From: Fran?ois <francoisleygues@yahoo.com>
- Date: Sat, 22 Apr 2000 09:37:14 -0700 (PDT)
- To: www-rdf-interest@w3.org
So, there are several possible ways to express that.
May I suggest one ? It is perhaps less elegant than
what you say.
Suppose I want to define a Sequence of Literals.
There is a "metaclass"
<rdf:Description rdf:ID="ConstrainedContainer">
<rdf:type
rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class"
/>
<rdfs:subClassOf
rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class"
/>
</rdfs:Class>
whose instances, which are classes, support a "class
property"
(similar to smalltalk class variables) ,
<rdf:Property rdf:ID="ContainerConstraint">
<rdfs:domain rdf:resource="#ConstrainedContainer">
<rdfs:range
rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class">
</rdf:Property>
I can then define the LiteralSeq class :
<rdf:Description rdf:ID="LiteralSeq">
<rdfs:subClassOf
rdf:resource="http://www.w3.org/2000/01/rdf-schema#Seq"/>
<rdf:type rdf:resource="#ConstrainedContainer">
<ContainerConstraint
rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
</rdfs:Description>
and use it :
<rdfs:Class rdf:resource="LiteralOrSeq"/>
I dont know if I can add a superclass to an RDF core
class, but i trust you :
<rdf:Description
rdf:about=""http://www.w3.org/2000/01/rdf-schema#Literal">
<rdfs:subClassOf rdf:resource="#LiteralOrSeq"/>
</rdf:Description>
<rdf:Description rdf:about="#LiteralSeq">
<rdfs:subClassOf rdf:resource="#LiteralOrSeq"/>
</rdf:Description>
<rdf:Property ID="myprop">
<rdfs:range rdf:resource="#LiteralOrSeq"/>
</rdf:Property>
<rdf:Description about="http://somwhere/something">
<myprop>
<LiteralSeq>
<rdf:li>literal1</rdf:li>
<rdf:li>literal2</rdf:li>
<rdf:li>literal3</rdf:li>
</LiteralSeq>
</myprop>
</rdf:Description>
Is this reasonable ?
Note that the ICS-FORTH validating RDF parser dont
want to validate li elements for containers which are
not Bag Seq or Alt....
In any case, I think we need something like either an
addition to RDFS,
or at least a general purpose guideline to
author RDF schemas. What do you think ?
Bye.
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Received on Saturday, 22 April 2000 12:37:17 UTC