XForms CR - 7.10.1 Another XPath 1.0 Conformance Question

This question is, for a short time, posted only to the three XForms lists. I 
have other concerns about 7.10.1 which I will post separately.

It seems to me that the XForms CR may be using the instance() function and 
its related location paths in a way inconsistent with XPath 1.0.

I make the point in the assumption that John Boyer's recent email gives an 
accurate description of the relationship between instance data and the 
containing document. I am assuming that there is a *copy* of part/all of the 
content of an <xforms:instance> element in a separate XPath data model.

There are background uncertainties since Micah Dubinko's recent post on 
XML-Dev is by no means clearly expressing the same meaning as John Boyer's 
email. Nor has the XForms WG responded to my question regarding the precise 
meaning of "instance data" and its scope.

My concern relates to the following syntax in the CR:
ref="instance('orderform')/shipTo/firstName"

The instance() function seems to me to reference the id attribute containing 
the value "orderform". As I understand the situation that id attribute only 
exists in the original/containing document or, more precisely, in the XPath 
data model which represents it. As far as I understand it a representation of 
that <xforms:instance> and its id attribute do not exist in the *copy* XPath 
data model. Therefore the instance() function in the first location step of 
the quoted location path is referencing a node in the XPath data model of the 
original/containing document.

However, again if I am understanding correctly, the two following location 
steps  reference *the copy* XPath data model (not the XPath data model of the 
original/containing document).

So we seem to have a single XPath 1.0 location path apparently operating on 
two separate XPath 1.0 data models.

To the best of my knowledge that is inconsistent with XPath 1.0.

Andrew Watt

Received on Monday, 18 November 2002 08:26:13 UTC