Problem

SPARQL does not include support for easily querying the members of an rdf:list. Glitter does not provide any custom support for querying lists either.

Goal

• Add a Glitter functional predicate list:member that relates the head of a list to all items in the list
• Ensure that list members are returned in the order they appear in the list, in the absence of other ORDER BY criteria
• Ensure acceptable performance

Other Designs

• ARQ has supported a list:member property for a long while. It might help interoperability to reuse the same predicate.
• cwm supports list:in with similar semantics but a different predicate from ARQ

Performance Considerations

Test querying of large lists. Test querying of small lists in large datasets. Test sub-ordering conditions.