Re: XForms CR - 7.10.1 Another XPath 1.0 Conformance Question

In a message dated 18/11/2002 19:28:07 GMT Standard Time, JBoyer@PureEdge.com 
writes:


> An excellent exposition, Ryan.
> 
> In essence, XPath functions supplied by the consuming application are free 
> to access out of band data.  For another example of a function that does 
> something like this, see the here() function in the XML Signature 
> recommendation.
> 
> John Boyer, Ph.D.
> Senior Product Architect
> PureEdge Solutions Inc.

John,

The here() function in XML Signature is an interesting comparison. I assume 
you are intimately familiar with it.

One aspect of the description of the here() function is as follows,
"This expression results in an error if the containing XPath expression does 
not appear in the same XML document against which the XPath expression is 
being evaluated."

At least at first glance what the XForms WG is suggesting is legimate is what 
is stated normatively to be an error for the XML Signature here() function.

I would be interested in your exposition of why, when the instance() function 
does something similar to the here() function, it too should not generate an 
error.

Andrew Watt