- From: Gerhard Wickler <Gerhard.Wickler@informatik.uni-stuttgart.de>
- Date: Tue, 22 Jun 2004 11:58:33 +0200
- To: Drew McDermott <drew.mcdermott@yale.edu>
- Cc: public-sws-ig@w3.org
Drew, I agree that XML literals are certainly the right syntactical approach for representing preconditions and effects. The way I read your example is that you want to let an expression say what language it is in and then use that content language to describe preconditions and effects (similar to what KQML used to do). Is that correct? If so, I'm very much in favour of the flexibility this provides. The difficult part then will be to define the formal semantics of preconditions and effects. How are you planning to do that? Are you thinking of an approach similar to reification in RDF? Gerhard Drew McDermott wrote: > The current frontrunner is to represent conditions as literals, either > XML literals or some other kind. An attribute of a condition is its > logical language. Example: > > <owls:AtomicProcess> > <owls:hasPrecondition> > <owls:Expression expressionLanguage="&swrl;#SWRL" > rdf:parseType="Literal"> > <ruleml:body rdf:parseType="Collection"> > <swrl:individualPropertyAtom> > <swrl:propertyPredicate rdf:resource="creditCardAuth"/> > <swrl:argument1 rdf:resource="#cc"/> > <swrl:argument2 rdf:datatype="&xsd;#string">Yes</swrl:argument2> > </swrl:individualPropertyAtom> > </ruleml:body rdf:parseType="Collection"> > </owls:Expression> > </owls:hasPrecondition> > </owls:AtomicProcess> > >The reason to use literals is to "hide" the RDF from the main RDF >parser. What a knowledgeable Owl-S parser must actually do is >re-parse the hidden RDF chunks later, when it's possible to do >appropriate substitutions. In the example above, the >individualPropertyAtom is not really about the variable "#cc"; it's >about the _value_ of that variable in some context. When that value >is available, the RDF can be reprocessed to yield a statement about >the authorization status of that credit card. > > >
Received on Tuesday, 22 June 2004 05:58:02 UTC