[xquery-talk] Question about default context node

Alex biz1 at creatiweb.com
Fri Sep 17 16:57:27 PDT 2004


Thanks for your answer! 

Which mechanism would you recommend for input data, external var or 
context node? My use case would be one XML document in, one XML 
document out, similar to an XSLT transformation with JAXP/TRAX. 

Do you know if other implementations also support the context node 
concept?

thanks,
alex 


> The key thing here is appendix C.2, which indicates that there is no
> language-predefined default for the initial value of the context 
item, but
> that a value can be supplied "by the implementation" - which in 
practice
> means that the implementation can provide means for the user to set 
a value
> via an API. An implementation could if it wished always set this to 
a fixed
> value (for example it could always set the initial context item to 
the
> integer zero or to a random number) but that seems an unlikely 
choice to
> make. The language spec is very careful to steer clear of API issues.
> 
> As for XQJ, I think there are lots of things missing from the 
current drafts
> of XQJ. I suspect (I certainly hope) that the final spec will move 
on a fair
> bit from the draft that we've seen.
> 
> Michael Kay
> 
> > -----Original Message-----
> > From: talk-bounces at xquery.com 
> > [mailto:talk-bounces at xquery.com] On Behalf Of Alex
> > Sent: 17 September 2004 18:27
> > To: talk at xquery.com
> > Subject: [xquery-talk] Question about default context node
> > 
> > Hi,
> > 
> > is a default context node part of the XQuery standard? I'm getting 
> > conflicting messages. For one, I heard statements that you 
> > need to use 
> > doc(), collection() or external variables to pass in data to an 
> > XQuery. On the other hand, implementations like Saxon provide 
methods 
> > like setContextNode() in their Java API so a simple XPath 
like /a/b/c 
> > is also a valid XQuery that makes sense. I like the context node 
> > option because of its simplicity but am not sure if it's standard. 
I 
> > haven't seen support for it in XQJ.
> > 
> > I would appreciate any clarification and references to the XQuery 
> > standard concerning context nodes set from the API.  
> > 
> > Thanks,
> > alex
> > _______________________________________________
> > talk at xquery.com
> > http://xquery.com/mailman/listinfo/talk
> > 
> 
> 
> 

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