Unification of the rule-based system languages to provide interoperability of declarative programs

The W3C standard RIF (Rule Interchange Format) that is provided for the interoperability of various rule based systems by the introduction of the extensible family of unified languages (dialects) oriented on creation of semantic preserving mappings of rule based languages of various systems into the dialects is analyzed. To characterize the motivation for the RIF project, a short survey of development and application of rule based languages and systems in the areas of knowledge representation, deductive databases, and logical reasoning is made. Various semantics of logical rule based languages that influenced the RIF decisions are also analyzed. Main classes of application cases of the interoperable rule based programs used for development of the requirements for RIF are considered. Finally, the main decisions of the RIF project are overviewed.