Recursive Select Using XPath 2.0

[muchomagic]

Hi all,

I'm attempting to write an XPath expression that can follow references recursively. I'm doing this for a Schematron rule, so it's not in an XSLT template that I can modify.

The setup:

<strawberry id="strawberry-1">
  <extends ref_id="berry-1"/>
</strawberry>
<berry id="berry-1">
  <extends ref_id="fruit-1"/>
  <extends ref_id="plant-1"/>
</berry>
<fruit ref_id="fruit-1"/>
  <extends ref_id="food-1"/>
  <extends ref_id="sweet-1"/>
</fruit>
<plant id="plant-1"/>

That's some sample data. Now what I need to do is create a collection of nodes that includes strawberry and every node up the hierarchy from strawberry (and by hierarchy, I mean the hierarchy created by the data...not an XML structure hierarchy).

Something like this selects strawberry's immediate parents: //*[@id eq //strawberry/@ref_id], but I need to select strawberry, its parents, their parents, their parents, etc. to the N-th level (basically, trace up every branch in the hierarchy until every branch ends, and then include all of the nodes in the tree). Also note that each element may extend 0-* other elements.

Any thoughts would be greatly appreciated.

Thanks!