[xquery-talk] flowrrr - how to structure a function?

John Snelson jsnelson at sleepycat.com
Tue Oct 17 15:35:58 PDT 2006


Hi Robert,

It shouldn't matter which order functions are evaluated in, since XQuery 
functions are meant to be side-effect free. In the case of your query, 
what that means is that the attribute setting and redirection should be 
queued up to be executed after the query has finished - this is what 
happens in the XQuery Update specification.

As it happens, all the functions that you use are probably just setting 
name-value pairs to be output in the HTTP response header, so their 
order won't matter there either.

John

Robert Koberg wrote:
> I wonder how other processors work. I read somewhere that you can use 
> Saxon as eXist's XQuery processor, which I intend to do for validity and 
> performance comparisons.
> 
> Do other processors evaluate sequences in order?
> 
>>>> So theoretically an XQuery engine might choose to first evaluate
>>>> session:set-attribute($project-key,
>>>> $group-name),response:redirect-to(xs:anyURI("./project/"))
>>>>
>> FYI. I asked on the eXist list and Wolfgang Meier responded with:
>>
>> "No. The functions will be evaluated in the same order as they are
>> added to the sequence. No problem here."
>>
> 
> -Rob
> 
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