<foo>

  <!-- These elements will print due to the implicit rule -->
  <xyz printme="true">
    <abc printme="true"/>
  </xyz>

  <!-- This element has no associated rule and no implicit rule 
       applies for it because the printme attribute is not set. -->  
  <xyz/>

  
  
  <!-- This element will not be printed even if its printme 
       attribute  is set because implicit rules are invoked only 
       if no explicit rule matches the element. The */foo rule
       matches the following element.
       --> 
  <foo printme="true"/>

</foo>