Saxon is in fact able to handle extension functions that accept or return DOM Nodes and NodeLists, but there are a number of restrictions. In particular, if you return a DOM Node or NodeList then it must contain nodes that belong to an existing Saxon document, for example the document that was supplied as a DOMSource when the query or transformation started.
NodeInfo is an interface rather than an implementation, and the way that you create instances depends on which implementation of NodeInfo you are using. The two native implementations, referred to as the tiny tree and the standard tree, are immutable document implementations, which means that you create an entire tree in one go, typically but not necessarity by parsing a source XML file, and you cannot then modify it. There are also implementations of NodeInfo that act as wrappers over DOM, JDOM, or XOM nodes.
There is some overview documentation of the NodeInfo interface in the documentation under "Java API", and more detailed documentation in the JavaDoc files.
For this kind of enquiry, it would be useful to know what problem you are trying to solve, and what the constraints are on the solution. It might be that there is a much better way to solve it than by writing extension functions that return a NodeList.
Michael Kay

From: [] On Behalf Of Namrata Patel
Sent: 14 March 2005 20:29
Subject: [saxon] NodeInfo



            I am trying to write an extension function that returns a NodeList. I understand that with Saxon, all the nodes must be instances of NodeInfo. My question is, how do I create elements and attributes using NodeInfo?? i.e. how do I use NodeInfo? I can’t find any documentation on it.