Question

I have an XML document with a section similar to the following:

<release_list>
  <release>
    <id>100</id>
    <file_list>
      <file>
        <id>20</id>
      </file>
      <file>
        <id>21</id>
      </file>
    </file_list>
  </release>
  <release>
    <id>101</id>
    <file_list>
      <file>
        <id>22</id>
      </file>
      <file>
        <id>21</id>
      </file>
    </file_list>
  </release>
  <release>
    <id>102</id>
    <file_list>
      <file>
        <id>22</id>
      </file>
      <file>
        <id>23</id>
      </file>
    </file_list>
  </release>
</release_list>

At some point I have XSL for-each statements looping through each release, and in turn through each list of files. While I’m looping through each file, I want to get information about which other releases DO NOT contain that same file ID. (So for example, when I’m iterating through file 20 in release 100, I want to get pointers to both releases 101 and 102, but when I’m iterating through file 21 in that same package I want only a pointer to release 102.)

Is there a way to do this with XPath? The closest thing I’ve come up with is:

../../../release[ not( file_list/file/id = ./id ) ]

…which of course fails because within the square brackets the ‘./’ refers to the release in front of the brackets, not the file that the XPath statement is being called from.

Anything I’m missing here?

Answer 1

A good approach in XSLT to things like this is to use a variable at the outer level, and then you can compare against it in your selection path. So, for instance, something like

<xsl:variable name="id" select="id" />
<xsl:apply-templates select="/release_list/release[not(file_list/file/id = $id)]" />

may help you.