<xpp>

<!-- Define the ancestor class XPlant -->

<class name="XPlant" inherit="">

<construct>

<scope type="public">

<Num upd="false">100</Num>

</scope>

</construct>

<scope type="public">

<var type="int" name="iAge">5</var>

</scope>

</class>

<!-- Define the XTree class which inherits from XPlant but adds nothing else -->

<class name="XTree" inherit="XPlant"/>

<!-- Instantiate the MyTree object as an instance of XTree -->

<node name="MyTree" class="XTree" processcode="true" construct="true"/>

<!-- Write the iAge member of MyTree in a sentence -->

<xout processcode="true">

<eval>

<parm type="int" name="Parm0">

<eval object="MyTree" member="iAge"/>

</parm>

<expr>"\r\nMyTree's age is " + Parm0 + " years old."</expr>

</eval>

</xout>

<!-- Write the upd attribute of the Num child node of the MyTree object -->

<xout processcode="true">

<eval>

<parm type="string" name="Parm0">

<eval object="MyTree/Num" attribute="upd"/>

</parm>

<expr>"\r\nMyTree/Num's upd flag is " + Parm0</expr>

</eval>

</xout>

<!-- Assign the Barn node to be the new value of MyTree -->

<eval object="MyTree">

<Barn>500</Barn>

</eval>

</xpp>