[xquery-talk] XQuery and Web 2.0

Thomas Lord lord at emf.net
Fri Apr 25 11:41:08 PDT 2008

Michael Kay wrote:
>> 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. [....]
> 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.

Yes.  In this case, the "pipeline language" is simpler and more general.

It is simpler in that has but one control construct (continuation 
passing);  more general in that programs can arbitrarily construct their 
continuations on the fly.

On the list of areas to possibly explore in the future is the idea of 
writing (in Flower) an interpreter or compiler (to Flower) for the 
standardized and / or popular pipeline languages.


> Michael Kay
> http://www.saxonica.com/
> _______________________________________________
> talk at x-query.com
> http://x-query.com/mailman/listinfo/talk

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