Alloy*: A General-Purpose Higher-Order Relational Constraint Solver
The last decade has seen a dramatic growth in the use of constraint solvers as a computational mechanism, not only for analysis of software, but also at runtime. Solvers are available for a variety of logics but are generally restricted to first-order formulas. Some tasks, however, most notably thos...
Main Authors: | , , , |
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Other Authors: | |
Format: | Article |
Language: | en_US |
Published: |
Institute of Electrical and Electronics Engineers (IEEE)
2018
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Online Access: | http://hdl.handle.net/1721.1/116144 https://orcid.org/0000-0002-0194-3989 https://orcid.org/0000-0003-4864-078X |
Summary: | The last decade has seen a dramatic growth in the use of constraint solvers as a computational mechanism, not only for analysis of software, but also at runtime. Solvers are available for a variety of logics but are generally restricted to first-order formulas. Some tasks, however, most notably those involving synthesis, are inherently higher order; these are typically handled by embedding a first-order solver (such as a SAT or SMT solver) in a domain-specific algorithm. Using strategies similar to those used in such algorithms, we show how to extend a first-order solver (in this case Kodkod, a model finder for relational logic used as the engine of the Alloy Analyzer) so that it can handle quantifications over higher-order structures. The resulting solver is sufficiently general that it can be applied to a range of problems; it is higher order, so that it can be applied directly, without embedding in another algorithm; and it performs well enough to be competitive with specialized tools. Just as the identification of first-order solvers as reusable backends advanced the performance of specialized tools and simplified their architecture, factoring out higher-order solvers may bring similar benefits to a new class of tools. |
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