Extending and implementing RASP

In previous work an extension of ASP, called RASP (standing for ASP with Resources), has been proposed. RASP supports declarative reasoning on production and consumption of (amounts of) resources. The approach combines stable model semantics with quantitative reasoning and relies on an algebraic structure to support computations and comparisons of amounts. The resulting framework also offered some form of preference reasoning on resources usage. In this paper we go further in this direction by introducing more expressive constructs to support complex preferences specification. The complexity of establishing the existence of an answer set, in such an enriched framework, is then shown to be NP-complete. A prototypical implementation of RASP has been realized. The tool, named \emph{raspberry}, consists in a compiler that, given a ground RASP program, produces a pure ASP encoding suitable to be processed by commonly available ASP-solvers.