as *unfounded-based* and *aggregate-based* inferences [@DBLP:journals/ai/GebserKS12]. The framework for specifying heuristics has been implemented in *C++* and it offers an infrastructure for easy specification and testing of heuristic strategies. The user can adopt several languages for implementing external heuristics that range from imperative to declarative ones. In particular, the heuristic strategies can be implemented in *perl* and *python* for obtaining fast prototypes and in *C++* for obtaining better performances. (In our tests, we observed that *C++* implementations are often faster than equivalent *perl* and *python* counterparts, which are usually easier to develop instead). In case the user would like to use a declarative language to implement a heuristic, our implementation provides a *predicates-based* interface extending the one proposed in [@DBLP:conf/aaai/GebserKROSW13]. We next sketch the idea by assuming that (on the lines of in [@DBLP:conf/aaai/GebserKROSW13]) one encodes the heuristic strategy in ASP by providing a logic program $\Pi$. Each request of the CDCL algorithm causes an evaluation of $\Pi$ together with *facts* modeling the request (intuitively, a fact is an atom that is always true). The evaluation of $\Pi$ with the aforementioned facts produces a set of atoms (i.e., the answer set produced by a solver) interpreted as responses for the 