<?xml version="1.0" encoding="UTF-8"?>
declare function local:section-summary($book-or-section as element()*)
  as element()*
{
  for $section in $book-or-section
  return
    <section>
       { $section/@* }
       { $section/title }	
       <figcount>		
         { count($section/figure) }
       </figcount>		
       { local:section-summary($section/section) }			
    </section>
};

<toc>
  {
    for $s in doc("book.xml")/book/section
    return local:section-summary($s)
  }
</toc>