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Rulewerk is a toolkit for using rules for knowledge modelling, data integration, and declarative computing. It integrates the rule engine VLog with many high-level features for knowledge base management and rule manipulation.

Usage

Rulewerk can be used in two ways:

• As a Java library in your own programming projects
• As a stand-alone client application (experimental)

Rule language

The rule language supported by Rulewerk is an extension of Datalog rule with several useful features:

• Stratified (i.e., non-recursive) negation
• Existential quantifiers in rule heads (value invention)
• Diverse data sources, including dynamic integration of results from SPARQL endpoints

Rulewerk provides reasoning and query answering capabilities for this language.

Data integration

Rules and facts can be loaded from a variety of sources:

• The native RLS syntax of Rulewerk supports the definition of rules, facts, and external data sources
• Knowledge bases in the DLGP format of the Graal rule library can be loaded
• Rulewerk can convert many OWL ontologies into equivalent rules, e.g., for query answering over OWL
• Data can be retrieved from RDF and CSV files
• Data can be obtained via the SPARQL query language from local or remote graph databases
• Data can be defined programmatically in Java

Further features

Rulewerk provides a full-fledged Java API for working with rules, including features for analysis and manipulation of knowledge bases.

• Loading, manipulating, and serialising of rules, facts, and data sources
• Query answering and export of inferences to files
• Static analysis of rule sets (e.g., for checking acyclicity conditions, which guarantee the termination of materialisation-based reasoning).