Extending Timbuk to Verify Functional Programs

Timbuk implements the Tree Automata Completion algorithm whose purpose is to over-approximate sets of terms reachable by a term rewriting system. Completion is parameterized by a set of equations defining which terms are equated in the approximation. In this paper we present two extensions of Timbuk which permit us to automatically verify safety properties on functional programs. The first extension is a language, based on regular tree expressions, which eases the specification of the property to prove on the program. The second extension automatically generates a set of equations adapted to the property to prove on the program.