[xsl] Selecting elements from source document based on matches to a second document

["Trevor Nicholls trevor@xxxxxxxxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Greetings

 

The requirement (preferably XSL 2)  is to filter a log of source code edits
by a list of paths held in a separate document. I can't believe there's not
an elegant way of doing this in XSL but I haven't yet managed to find one.

 

For example, given an input document which contains the log (empty elements
below aren't empty, they are just to show the structure)

 

<log>

  <logentry>

    <author/>

    <date/>

    <paths>

      <path>/here/a/document</path>

      <path>/there/another/document</path>

      ..

    </paths>

    <msg/>

  </logentry>

 <logentry/>

  <logentry/>

  ..

</log>

 

and a comparison document which contains a list of paths

 

<checkpaths>

  <path>/there/another/document</path>

  <path>/over/the/hills/and/far/away</path>

  <path/>

  <path/>

  ..

</checkpaths>

 

I would like to produce an output document which consists of a log
containing all the log entries where at least one of the logentry paths
matches a path in the checkpaths document, and where the paths for each
output logentry are limited to the matching paths.

 

What would be the best way of achieving this? (And if there's a much cleaner
method in XSL 3 I would be interested in seeing it, but our application is
still using XSL 2 for the time being)

 

To fill in the picture a bit, at the moment I am using the checkpaths list
to generate a separate log document for each path, then combining and
deduplicating the resultant logs, and doing it that way is the bottleneck in
the workflow. So I hope that the approach outlined above may be
significantly faster. And if it's not, well, I may still have learned a
potentially useful technique.

 

cheers

T