Re: Scope

Hi Geoff,

> I put together a simple example of using RuleML to specify a query against
> RDF and to return results. You can check it out at
> http://209.198.94.130/ruleml/query.asp. You specify your query as an
> implication and the url of the rdf file you want to query. The results are
> returned as RuleML <fact>s. I think I got the RuleML right, but please let
> me know otherwise.

Looks great!

In your sample query, note that the end tag for roles is </_opr>, </_head>, etc.,
while a comment would be <!-- opr --> etc.

> A few questions that came up in the process:
> 
> - how should type be handled? i.e. how should the uri "www.w3.org" be
> distinguished from the literal "www.w3.org"? an attribute could be added to
> <ind>? or just use syntax convention with text values -- [www.w3.org] vs.
> 'www.w3.org'?

In your results, RuleML 0.8 would use the empty element <ind href="http://..."/>
with an href attribute rather than <ind>http://...</ind>. While "http://..." is
not a typed attribute value, the attribute name, href, at least gives us a hint
that a URI is being expected.
We are currently working on real RuleML typing, connecting RuleML axioms with
RDFS taxonomies in order to obtain full ontologies.

> - it would be nice to be able to use namespaces in <ind> values. I guess
> there's no way with the current syntax to get them for free - i.e. get the
> parser to expand them. Absent that, a convention such as passing along alias
> information as additional <fact>s might be handy.

Sounds like a good start. Perhaps, you could work out something together with
(other) RuleML Participants. I gather you are not talking about the RuleML
namespace itself but about the URIs' namespaces referred to, in the metadata-like
way of our SWWS paper http://www.mynisus.com/members/stabet/ruleml/ratioruleml.pdf
(Said could you check whether the Nisus server is up?).

> Overall, seems to work pretty well. It doesn't seem like too much of a
> force-fit or misuse of the language and results aren't too verbose.

Yes, thanks for showing this so fast!

BTW, we might also wish to specify the corresponing RuleML sublanguage DTD for
a generated result rulebase.

Cheers, Harold

Received on Wednesday, 21 November 2001 15:44:18 UTC