The Evidential Tool Bus (ETB) is a distributed framework for tool integration for the purpose of building and maintaining assur- ance cases. ETB employs Datalog as a metalanguage both for defining workflows and representing arguments. The application of Datalog in ETB differs in some significant ways from its use as a database query language. For example, in ETB Datalog predicates can be tied to exter- nal tool invocations. The operational treatment of such external calls is more expressive than the use of built-in predicates in Datalog. We out- line the semantic characteristics of the variant of Datalog used in ETB and describe an abstract machine for evaluating Datalog queries.
['Simon Cruanes', 'Stijn Heymans', 'Ian Mason', 'Sam Owre', 'Natarajan Shankar']
The Semantics of Datalog for the Evidential Tool Bus (Extended Abstract)