../../description

This xpath expression searches in the same node and the structure information was extracted properly.
(Credit goes to my colleague Mira)

Dimmo Petrov

Thanks for this.  I think you're highlighting an important point that  noted out in this thread about relative references:

https://community.rws.com/product-groups/trados-portfolio/trados-studio/f/studio/40389/xml-comment-xpath

Maybe worth a further explanation for anyone who doesn't completely follow this (it took a few times for me to understand this concept too).  The expression asks for a relative path which means the expression starts from the node (or element) you are in and not from the root of the xml file.  In this case your parser rule sets your position in the file:

//Text[@translate="true"]

This is an absolute expression starting from the root, resolving itself by positioning you in the <Text> node.  To get to the <description> node from here you have to traverse up the file through two nodes, and the shortform of taking a parent node is the double dot.  So, using this which was in the initial post

//description

will get you the absolute value of the first <description> node it finds every time you parse through the xml file to extract a segment. The <description> node is actually a child of a parent of a parent of the <Text> node you are currently in:

<request id="1129" source-language="da" type="LanguageText">
    <translation destination-language="fr">
        <Text translate="true">Planlagt driftstid</Text>
    </translation>
    <current-translation>Temps de fonctionnement programmé</current-translation>
    <description>Label describing the number of hours a plant is scheduled to be in operation this year</description>
</request>

The parent being <translation> and the parent of the parent being <request>.  Finally, <description> being a child of <request>.  So you need to traverse up from <Text> through two parent nodes like this:

../../description

or this

parent::*/parent::*/description

or this

parent::translation/parent::request/description

Writing this actually cements this understanding in my own head so it's a bit of self-therapy as well as hopefully being useful for others.

Thank you very much Paul! All this is extremely useful!