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This document is also available in these non-normative formats: XML.
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XPath 4.0 is an expression language that allows the processing of values conforming to the data model defined in [XQuery and XPath Data Model (XDM) 4.0]. The name of the language derives from its most distinctive feature, the path expression, which provides a means of hierarchic addressing of the nodes in an XML tree. As well as modeling the tree structure of XML, the data model also includes atomic items, function items, maps, arrays, and sequences. This version of XPath supports JSON as well as XML, and adds many new functions in [XQuery and XPath Functions and Operators 4.0].
XPath 4.0 is a superset of XPath 3.1. A detailed list of changes made since XPath 3.1 can be found in I Change Log.
This is a draft prepared by the QT4CG (officially registered in W3C as the XSLT Extensions Community Group). Comments are invited.
The publications of this community group are dedicated to our co-chair, Michael Sperberg-McQueen (1954–2024).
Michael was central to the development of XML and many related technologies. He brought a polymathic breadth of knowledge and experience to everything he did. This, combined with his indefatigable curiosity and appetite for learning, made him an invaluable contributor to our project, along with many others. We have lost a brilliant thinker, a patient teacher, and a loyal friend.