Content area
This thesis proposes a novel idea of retrieving the XPath intermediate path nodes. We formally define an extension of the current XPath semantics that makes XPath be able to retrieve the XPath path nodes. We design an XPath traversing tree structure that seamlessly models XPath expressions. With a simple XPath expression rewriting algorithm, we can obtain all XPath path nodes utilizing the current XPath semantics evaluation. If using a polynomial time XPath evaluating algorithm, our algorithm can also achieve a polynomial order complexity with respect to the size of XML document and the number of steps in the XPath expression. We further implement a visual XPath debugging framework, called XPlainer. XPlainer can visually navigate in the XML tree through the XPath path. It provides a visual explanation on how the XPath expression selects and filters the nodes in the XML tree. It also provides an useful XPath debugging function.