Here is a simple XML/XSL tree navigation. I have made almost all XML/XSL navigations based on this XSL.
XSL transforms XML tree to XHTML list view.
XSLT Standard Library
The XSLT Standard Library, xsltsl, provides the XSLT developer with a set of XSLT templates for commonly used functions. These are implemented purely in XSLT, that is they do not use any extensions.
xsltsl is a SourceForge project.
FXSL — the Functional Programming Library for XSLT
Until now it was believed that although XSLT is based on functional programming ideas, it is not as yet a full functional programming language, as it lacks the ability to treat functions as a first-class data type. Based on numerous concrete XSLT implementations of some of the major functional programming design patterns, including some of the most generic list-processing and tree-processing functions, this article provides ample proof that XSLT is in fact a full-pledged functional programming language. The presented code forms the base of a first XSLT functional programming library. It is emphasized that a decision to include higher-order functions support in XPath 2.0 will make functional programming in XSLT even more straightforward, natural and convenient.