Invariant-Driven Strategies for Maude

Combining Runtime Checking and Slicing to Improve Maude Error Diagnosis

“…On the one hand, our assertions are external and evaluated at runtime, whereas driving the system's execution in such a way that every computation state complies with the constraints makes the assertions internal to the programmed strategy. On the other hand, the strategy of [16,28] never results in violated assertions, which is essential for automatic trace slicing to be fired according to our approach. As another difference, we are able to check assertions that regard: 1) the normalizations carried out by using the equational part of the rewriting theory; and 2) system properties that are not necessarily global invariants but can only hold in those states that match a given state template.…”

“…Nevertheless, to the best of our knowledge, no general built-in support is provided in Maude or the MFE for the runtime checking of user-defined assertions. Related to our work, generic strategies are defined in [16,28] to guarantee that a set of invariants (that can be expressed in different logics) are satisfied at every computed state. This is achieved by avoiding the execution of actions that otherwise would conduct the system to states that do not satisfy the constraints.…”

Formalizing ODP computational viewpoint specifications in Maude

“…As previously mentioned, such conditions can be expressed in different logics. We have already experimented with predicates expressed in propositional logic and linear temporal logic [8]. The temporal logic we have considered is the same that Maude uses in its model checker [11], and the approach used to deal with temporal logic is similar to the one proposed by Havelund and Roşu in [15] for monitoring Java programs.…”

“…Different built-in strategies for executing specifications are available in Maude, and also facilities for defining our own rewriting strategies are available [5], thus guiding the rewrites depending on our specific needs. The detailed process for expressing constraints and invariants on the system and for defining execution strategies based on them is outside the scope of this paper, and has been reported in [8].…”

“…ODP's notion of subtyping-A is a subtype of B if every <X> that satisfies A also satisfies B-corresponds to Maude's class inheritance. On the other hand, the ODP's notion of inheritance, that allows the suppression and modification of the attributes and methods of the base class [17,[2][3][4][5][6][7][8][9].21] corresponds to Maude's module inheritance. Throughout the paper, by inheritance we will mean Maude's notion of class inheritance, i.e.…”