XQuery and Web 2.0

[Michael Kay]

> In my systems, I handled sequencing by evaluating XQuery 
> programs in a loop, each iteration of the loop returning a 
> description of side effects 
> to perform and, optionally, a continuation.   If present, the 
> continuation is the next XQuery program to run in the loop.   This is 
> simple and effective although it is unusual enough that it 
> takes some time to get used to it.

This sounds like a classic pipeline architecture, and can be controlled
using a pipeline language such as XProc or Orbeon XPL. Because it keeps the
size of individual queries small, this is definitely a good way of creating
XQuery applications. It also allows XQuery to be mixed with other
technologies (such as XSLT and Java apps) in the same pipeline.

Michael Kay
http://www.saxonica.com/