[xquery-talk] SPARQL to XQuery transformation

Michael Kay mike at saxonica.com
Wed Apr 29 09:28:55 PDT 2009

XQuery is Turing-complete, so there shouldn't be any theoretical problems.
It could be that there are issues to do with data model coverage - for
example XQuery 1.0 doesn't give access to unparsed entities, and doesn't
provide any way to create namespaces whose names aren't known statically.
But I think those are unlikely to be stopper issues.
Michael Kay


From: David A. Lee [mailto:dlee at calldei.com] 
Sent: 29 April 2009 01:33
To: Michael Kay
Cc: 'McBeath, Darin W (ELS-STL)'; talk at x-query.com; 'Vyacheslav Sedov'
Subject: Re: [xquery-talk] SPARQL to XQuery transformation

I don't believe its impossible either, but I was thinking, as a purely
functional language (if that makes a difference?)
Is there any set of computations that xquery couldn't theoretically execute,
that say a procedural language could ?

Michael Kay wrote: 

It might be *possible* to do in XQuery but its not a simple 

"translation" of one query language to another, it would take 

writing an inference engine in xquery.  quite a project.


If you can write an interpreter for a query language then you can write a

compiler for it. And compiling into XQuery is probably easier than compiling

into machine code. So as far as I can see, it doesn't look intrinsically

impossible at all.

Michael Kay



talk at x-query.com





David A. Lee

dlee at calldei.com  


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