child::*[self::chapter or self::appendix] selects the chapter and appendix children of the context node
<?xgrep-match [xgrep-test1.xml]--------------------------------?>
<chapter/>
<?xgrep-match [xgrep-test1.xml]--------------------------------?>
<chapter/>
<?xgrep-match [xgrep-test1.xml]--------------------------------?>
<chapter/>
<?xgrep-match [xgrep-test1.xml]--------------------------------?>
<chapter/>
<?xgrep-match [xgrep-test1.xml]--------------------------------?>
<chapter>
	  <section/>
	  <section>
	    Section2
	  </section>
	  <section/>
	</chapter>
<?xgrep-match [xgrep-test1.xml]--------------------------------?>
<chapter>
	  <title name="t1">Title</title>
	  <title name="t2">Introduction</title>
	  <title name="t3"/>
	</chapter>
<?xgrep-match [xgrep-test1.xml]--------------------------------?>
<chapter>
	  <title/>
	</chapter>
<?xgrep-match [xgrep-test1.xml]--------------------------------?>
<chapter/>
<?xgrep-match [xgrep-test1.xml]--------------------------------?>
<appendix/>