This XML parser uses the standard XML SAX parser (which in turn uses expat) to provide a SimpleXML-like data model in a streaming fashion. This way, you get the benefit of an in-memory model without having to load a whole document in memory.

To parse a document, you provide a path expression and a callback function. The path expression tells the parser when to use the callback as soon as a tree branch matching the path expression has been parsed. See the example use in the source code.