RuleML is a modular, webized Rule Markup & Modeling Language based on XML and RDF, developed by the Rule Markup Initiative.
Versions of the RuleML XML serialization have been used in all the rule submissions:
The Horn logic sublanguage of RuleML has been realized with rule engines such as the reference implementation OO jDREW, which can be developed into a RIF RuleML engine.
Translators (in XSLT and Java) between RuleML and other languages such as Prolog and Jess have been developed to support rule-system interoperation http://www.ruleml.org/#Translators.
Impact on Design
For Phase 2, classical Negation and Negation-As-Failure can be made available in separate sublanguages and in a combined one, as exemplified inside the Negation Datalog module http://www.ruleml.org/modularization/#Model. Various fragments of OWL can be -- homogeneous approach -- in subsets of SWRL http://www.w3.org/Submission/2004/SUBM-SWRL-20040521 or become -- heterogeneous approach -- DL queries in hybrid rules http://www.jdrew.org/oojdrew/exa/hybridrules.html.
For More Information
The RuleML Initiative http://www.ruleml.org and Conferences (http://2005.ruleml.org, http://2006.ruleml.org) have provided continuing expertise and exchange in the area of web rules. Also see the Charter entry http://www.w3.org/2005/rules/wg/charter#ruleml.