{section name=c loop=$chapters}
第 {$smarty.section.c.rownum} 章 {$chapters[c].name}
{assign var="sections" value=$chapters[c].sections}
{section name=s loop=$sections}
  {$smarty.section.c.rownum}-{$smarty.section.s.rownum} {$sections[s]}
{/section}
{/section}