Kristoffer Høgsbro Rose

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In this paper we consider rewrite systems that describe the-calculus enriched with recursive and non-recursive local deenitions by generalizing thèexplicit substitutions' used by Abadi, Cardelli, Curien, and L evy 1] to describe sharing in-terms. This leads tòexplicit cyclic substitutions' that can describe the mutual sharing of local recursive deenitions.(More)
As XQuery is gathering momentum as the standard query language for XML, there is a growing interest in using it as an integral part of the XML application development infrastructure. In that context, one question which is often raised is how well XQuery interoperates with other XML languages, and notably with XSLT. XQuery 1.0 [16] and XSLT 2.0 [7] share a(More)
Formal semantics for XQuery with side-effects have been proposed in [13, 16]. We propose a different semantics which is better suited for database compilation. We substantiate this claim by formalizing the compilation of XQuery extended with updates into a database algebra. We prove the correctness of the proposed compilation by mapping both the source(More)
We present the a w-calculus, a formal synthesis of the concepts of sharing and explicit substitution for weak reduction. We show how a w can be used as a foundation of implementations of functional programming languages by modeling the essential ingredients of such implementations , namely weak reduction strategies, recursion, space leaks, recursive data(More)
Although the Extensible Markup Language (XML) has gained in popularity and has resulted in the creation of powerful software for authoring, transforming, and querying XML-based business data, much information remains in non-XML form. In this paper we introduce an approach to virtualize data resources and thus enable applications to access both XML and(More)
An effective approach to support XML updates is to use XQuery extended with update operations. This approach results in very expressive languages which are convenient for users but are difficult to optimize or reason about. A crucial question underlying many static analysis problems for such languages, from optimization to view maintenance, is whether two(More)
x Abstract. We generalise the notion of explicit substitution from the-calculus to higher order rewriting, realised by combinatory reduction systems (CRSs). For every connuent CRS, R, we construct an explicit substitution variant, Rx, which we prove connuent. We identify a large subset of the CRSs, the structure-preserving CRSs, and show for any(More)
A common approach to XML updates is to extend XQuery with update operations. This approach results in very expressive languages which are convenient for users but are difficult to reason about. Deciding whether two expressions can commute has numerous applications from view maintenance to rewriting-based optimizations. Unfortunately, commutativity is(More)