The alignment of the design effort in the two specifications is evident by virtue of goals, stated identically for XPath 2.0 and XSLT 2.0: to "simplify manipulation of XML Schema-typed content, simplify manipulation of string content, support related XML standards, improve ease of use, improve interoperability, improve i18n support, maintain backward compatibility, and enable improved processor efficiency." Jonathan Robie, editor on some of the query specifications, writes: "The manner in which these specifications are intertwined [with W3C XML Schema] is: (1) XPath and XQuery will be using a common data model for XML; (2) This data model will be able to express XML documents that are well formed, use DTDs, or have schemas; (3) A formal algebra will be defined on this data model, and XQuery will be defined in terms of this algebra. The algebra will be hard to read, but it ensures that the language is well defined and well typed, so the other documents, e.g., the language specification and tutorials, become unambiguous and easier to read. In the long run, I think that the Schema Formalization effort, based on the earlier MSL work [see 'MSL: A Model for W3C XML Schema'], is a key player in allowing the data model and algebra to be defined in terms of Schema types..." [XML-DEV]
XPath Requirements Version 2.0. Reference: W3C Working Draft 14-February-2001. Edited by Steve Muench (Oracle), Mark Scardina (Oracle), and Mary Fernández (AT&T). XPath is a language for addressing parts of an XML document, designed to be used by both XSLT and XPointer. The new XPath requirements document has been written by members of the XSL Working Group and the XML Query Working Group; the document has been produced jointly as part of the W3C Style Activity and the W3C XML Activity. The goals of the XSL Working Group are discussed in the XSL Working Group charter, and the goals of the XML Query Working Group are discussed in the XML Query Working Group Charter. This Working Draft represents the current thinking of the XSL Working Group and XML Query Working Group. The groups have consensus except in a few specific areas as noted below and the details of these areas are still under active discussion. The specification builds upon the XPath 1.0 W3C Recommendation. XPath must support the XML 'Family' of Standards, e.g., (1) the XPath 2.0 data model must be expressed in terms of the XML Infoset, including Post Schema Validation Infoset contributions. Ideally, XSLT, XPath, and XML Query should share a common data model; (2) it must provide common core syntax and semantics for XSLT 2.0 and XML Query 1.0.
XSLT Requirements Version 2.0. Reference: W3C Working Draft 14-February-2001. Edited by Steve Muench (Oracle) and Mark Scardina (Oracle). The XSLT 2.0 requirements specification has been produced by the XSL Working Group as part of the W3C Style activity. XSLT is a language for transforming XML documents into other XML documents; it is designed for use as part of XSL, which is a stylesheet language for XML that also includes an XML vocabulary for specifying formatting. The XSLT version 2.0 goals are similar to those of XPath 2.0; it will build upon XSLT 1.0 W3C Recommendation and will support W3C XML Schema by "providing support for the common operations needed for matching and construction of transformed documents based on a source document containing these typed elements and attributes." XSLT 2.0 non-goals are: "simplifying the ability to parse unstructured information to produce structured results" and "turning XSLT into a general-purpose programming language."