- From: Dan Connolly <connolly@w3.org>
- Date: Fri, 21 Feb 2003 12:01:27 -0600
- To: www-rdf-comments@w3.org
In DAML+OIL, we had item, inferred from first/rest... <rdf:Property rdf:ID="item"> <rdfs:comment> for item(L, I) read: I is an item in L; either first(L, I) or item(R, I) where rest(L, R). http://www.daml.org/2001/03/daml+oil#item http://www.w3.org/TR/2001/NOTE-daml+oil-reference-20011218 In RDFS, member seems to have no relation to first/rest... http://www.w3.org/TR/2003/WD-rdf-schema-20030123/#ch_member http://www.w3.org/TR/rdf-schema/#ch_collectionvocab http://www.w3.org/TR/2003/WD-rdf-schema-20030123/#ch_collectionvocab I thought rdfs:member was specified ala daml:item to be inferred from first/rest. I did some implementation assuming those semantics... I was given a collection of a WG's documents, and I just wanted the documents. There's no single property that will get me from the WG to the documents, so I used rules to make up the difference... ------ { :GROUP a org:WorkingGroup; con:homePage :PG. :F is log:semantics of [ a :GroupKB]. (:F { this log:forAll :L, :X. { :L l:first :X } log:implies { :L l:item :X }. { :L l:rest [ l:item :X ] } log:implies { :L l:item :X }. }) log:conjunction [ log:conclusion :FLists ]. :FLists log:includes { [ a org:WorkingGroup; con:homePage :PG; wgi:hasDrafts [ l:item :WORK ] ] }. } log:implies { :GROUP org:deliverable :WORK }. ------- ... but that seems like a big hassle when the RDF parser could have just spit out rdfs:member triples along with rdf:first and rdf:rest triples. In sum... (1) pls specify that rdfs:member connects collections to their members (2) specify that parsers spit out rdfs:member triples when parsing Collection syntax. (3) specify that parsers spit out rdfs:member triples for old-style _n Containers too. Hmm... I suppose there could be missing member triples if the RDF/XML syntax used explicit first/rest or explicit rdf:_n triples. But that seems acceptable to me. This idea is probably too late to be worth the trouble. But it comes from real implementation experience, and I figure I ought to report the experience, even if the WG decides it's not worth the change at this point. -- Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Friday, 21 February 2003 13:01:28 UTC