Software

Let's not close without mentioning an extremely valuable resource if you're tracking what's going on with XQuery, http://www.w3.org/XML/Query, the W3C XML Query website. This is the official website of the working group , and just about everything relevant to XQuery gets posted here sooner or later, whether it's pointers to the latest specifications, news and articles on XQuery in the trade and technical press, information on the various discussion groups you can join or monitor, and an ever-growing list of real-life XQuery implementations .

Some of these are free, some are open -source (not always the same thing), some are full-strength, industrial products, and some come in the form of online demos. All the authors in this book are involved either directly or indirectly in XQuery- related software efforts at their various companies and research institutions (which shouldn't surprise anybody if you think about it, since most companies on the working group have XQuery projects under way), and a number of the authors of this book have been involved in the development of the software on this list.

Just to mention a few of these author/software connections: Mary Fern ndez, J r me Sim on, and Phil Wadler have all been involved in Lucent's implementation of Galax (which lets you make queries directly in the syntax of the formal semantics). Jim Tivy has already been mentioned in connection with XStreamDB. Jonathan Robie was active in Software AG's development of QuiP (which is a great reference implementation for hands-on exploration of XQuery syntax and semantics, although I'm told it's no longer being maintained ), and even I have an open-source, Java-based implementation called XQEngine. Please visit the XML Query website for an up-to-date listing of all the XQuery software that's currently available. The list is growing daily.