Abstract

The World Wide Web Consortium recommends both XSLT and XQuery as query languages for XML documents. XSLT, originally designed to transform XML into HTML, is nowadays a fully grown XML query language that is mostly suited for use by machines. XQuery on the other hand was particularly designed to be easily used by humans. Since both query languages receive a steady growth in user acceptance, it is important and natural to ask about their expressive power. We show here that both XSLT and XQuery are Turing-complete by reduction to µ-recursive functions. Keywords: XML, XSLT, XQuery, Turing-completeness 1

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