SPARQL path expressions refers to various ways of finding and matching structured paths of arbitrary lengths between nodes in an RDF graph. Path expressions could be used for, among other things, accessing lists.
Existing research and implementations:
- PSPARQL (or Path SPARQL) extends the SPARQL grammar to allow regular-expression operators on predicates in SPARQL graph patterns.
- SPARQLeR treats paths between RDF graph nodes as first-class objects that can be matched and filtered within a query.
- SPARQ2L takes a similar approach to SPARQLeR.
- GLEEN defines a path-expression syntax that pairs with two computed properties for accessing transitive closures and more arbitrary property paths.
( Virtuoso defines its own variable syntax as a shorthand for certain property chains.
- ARQ supports a wide variety of property paths.