[xsl] comparing XML document structure

[Graydon <graydon@xxxxxxxxx>]

So I have an XML document which defines the expected semantics of the
XML output of an SGML-to-XML conversion project as an exemplar; there
are structures like this, and like these, and like that.

I also have a whole bunch of XML output which ought to conform to that
semantics.  (This output is the product of a complex, multi-pass, highly
conditional set of XSLT transforms.)

The desired goal is to be able to programmatically pull the structure,
at least to the extent of parent-child element pairs, from the
semantics-defining file, and compare that to each output file in turn.

So if the semantics-defining file gives an example section element,
which has num, para, and subsection element children, what I want to be
able to do is create a sequence of axis relationships and test the
section elements of the output for axis relationships that are not
members of that sequence.

I'm nearly certain I can't do that, but thought it was much wiser to ask
and allow for the possibility of a pleasant surprise.

-- Graydon