Towards a Declarative Query and Transformation

Abstract. The growing importance of XML as a data interchange standard demands languages for data querying and transformation. Since the mid 90es, several such languages have been proposed that are inspired from functional languages (such as XSLT [1]) and/or database query languages (such as XQuery [2]). This paper addresses applying logic programming concepts and techniques to designing a declarative, rule-based query and transformation language for XML and semistructured data. The paper rst introduces issues specic to XML and semistructured data such as the necessity of exible \query terms " and of \construct terms". Then, it is argued that logic programming concepts are particularly appropriate for a declarative query and transformation language for XML and semistructured data. Finally, a new form of unication, called \simulation unication", is pro-posed for answering \query terms", and it is illustrated on examples.