About X (ML | Path | Query | SLT)

XML has become a very important format for data and document processing. Many languages have been recently developed for querying and transforming XML documents. The most prominent of these languages are XPath, XQuery and XSLT, that are correlated since XQuery and XSLT both use XPath. The complete description of these languages is vast and rather complex, and is surely not useful for educational reasons. Therefore we define three sublanguages, LiXPath, LiXQuery and LiXSLT, whose syntactical and semantical definitions are uniform, clean, selfcontained, compact and elegant. Furthermore the semantical structure of these three languages is completely different: LiXpath only can extract nodes; LiXQuery gives a new document as a result, depending on one or more documents. Finally, the process of the evalation of an XSLT stylesheet (ie. XSLT query) is remarkable, in the sense that it describes how the given stylesheet tree is transformed into the result document tree