XSE != XPath != SXPath != XPathReader

Note: this entry has moved.

Dare argues that my Xml Streaming Events API can't support queries like the following:

And argues that I'm adding extensions to XPath. I've mentioned in a previous post that I'm not doing that. I'm not *supporting* XPath. Therefore, the query testing for count of children won't work (for now). But the issue is a different one: XSE is not about querying with an specific expression language/format (i.e. XPath or SXPath). XSE is just a mechanism for encapsulating state machines checking for matches against a given expression. What the expression looks like depends on the factory that creates the strategy.
Therefore, the factories I showed (i.e. my RootedPath and RelativePath) are only encapsulating code generation for different FSMs, based on an expression language that fits a need. Therefore, I could even create a factory implementing SXPath and still remain in Xml Streaming Events land. The XSE idea is to provide a callback metaphor to XML parsing, instead of the pull-model of the XmlReader. In fact, it's a sort of evolution over SAX, in that at the same time it offers both worlds: pull model directly from the XseReader, events-based for your registered handlers.