[xquery-talk] Question about default context node

Michael Kay mhk at mhk.me.uk
Fri Sep 17 21:00:25 PDT 2004

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
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