Crate spareval

spareval

spareval is a SPARQL Query evaluator.

It relies on the spargebra and sparopt crates.

This crate is intended to be a building piece for SPARQL implementations like oxigraph.

use oxrdf::{Dataset, GraphName, NamedNode, Quad};
use spareval::{QueryEvaluator, QueryResults};
use spargebra::Query;

let ex = NamedNode::new("http://example.com").unwrap();
let dataset = Dataset::from_iter([Quad::new(
    ex.clone(),
    ex.clone(),
    ex.clone(),
    GraphName::DefaultGraph,
)]);
let query = Query::parse("SELECT * WHERE { ?s ?p ?o }", None).unwrap();
let results = QueryEvaluator::new().execute(dataset, &query);
if let QueryResults::Solutions(solutions) = results.unwrap() {
    let solutions = solutions.collect::<Result<Vec<_>, _>>().unwrap();
    assert_eq!(solutions.len(), 1);
    assert_eq!(solutions[0]["s"], ex.into());
}

Cargo features

• rdf-star: enables SPARQL-star.
• sep-0002: enables the SEP-0002 (ADJUST function and a lot of arithmetic on xsd:date, xsd:time, xsd:yearMonthDuration and xsd:dayTimeDuration).
• sep-0006: enables the SEP-0006 (LATERAL keyword).
• calendar-ext: arithmetic on xsd:gYear, xsd:gYearMonth, xsd:gMonth, xsd:gMonthDay and xsd:gDay.

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or <http://www.apache.org/licenses/LICENSE-2.0>)
• MIT license (LICENSE-MIT or <http://opensource.org/licenses/MIT>)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Oxigraph by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Structs

ExpressionTriple

InternalQuad

QueryEvaluator

Evaluates a query against a given RDF dataset

QueryExplanation

The explanation of a query.

QuerySolution

Tuple associating variables and terms that are the result of a SPARQL query.

QuerySolutionIter

An iterator over QuerySolutions.

QueryTripleIter

An iterator over the triples that compose a graph solution.

Enums

ExpressionTerm

A term as understood by the expression evaluator

QueryEvaluationError

A SPARQL evaluation error

QueryResults

Results of a SPARQL query.

Traits

DefaultServiceHandler

Default handler for SPARQL 1.1 Federated Query SERVICEs.

QueryableDataset

A RDF dataset that can be queried using SPARQL

ServiceHandler

Handler for SPARQL 1.1 Federated Query SERVICEs.