Using an XPath counter is not really that difficult, but due to the way dirxml script was implemented, one have to split the whole thing in two rules.

First setup a rule which initializes the variable which is used for the counter:


<rule>
<description>setVariables</description>
<conditions>
<and/>
</conditions>
<actions>
<do-set-local-variable name="lv_counter" scope="driver">
<arg-string>
<token-xpath expression="number(0)"/>
</arg-string>
</do-set-local-variable>
</actions>
</rule>


Notice the scope is set to driver, otherwise it will be local to the rule.

Then a rule which is using the counter:

...
<do-for-each>
<arg-node-set>
<token-text xml:space="preserve">//input/*</token-text>
</arg-node-set>
<arg-actions>
<do-set-local-variable name="lv_counter" scope="driver">
<arg-string>
<token-xpath expression="number($lv_counter) + 1"/>
</arg-string>
...


Then for each loop in the do-for-each loop it will count one up.