A Logical Approach to Deciding Semantic Subtyping

• Autores: Nils Gesbert, Pierre Genevès, Nabil Layaïda
• Localización: ACM transactions on programming languages and systems, ISSN 0164-0925, Vol. 38, Nº 1, 2015
• Idioma: inglés
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• Resumen

  • We consider a type algebra equipped with recursive, product, function, intersection, union, and complement types, together with type variables. We consider the subtyping relation defined by Castagna and Xu [2011] over such type expressions and show how this relation can be decided in EXPTIME, answering an open question. The novelty, originality and strength of our solution reside in introducing a logical modeling for the semantic subtyping framework. We model semantic subtyping in a tree logic and use a satisfiability-testing algorithm in order to decide subtyping. We report on practical experiments made with a full implementation of the system. This provides a powerful polymorphic type system aiming at maintaining full static type-safety of functional programs that manipulate trees, even with higher-order functions, which is particularly useful in the context of XML.