code: func matchLevel(l *level, toks []string, results *[]interface{}) {
  	var pwc, n *node
  	for i, t := range toks {
  		if l == nil {
  			return
  		}
  		if l.fwc != nil {
  			*results = append(*results, l.fwc.elements...)
  		}
  		if pwc = l.pwc; pwc != nil {
  			matchLevel(pwc.next, toks[i+1:], results)
  		}
  		n = l.nodes[t]
  		if n != nil {
  			l = n.next
  		} else {
  			l = nil
  		}
  	}
  	if pwc != nil {
  		*results = append(*results, pwc.elements...)
  	}
  	if n != nil {
  		*results = append(*results, n.elements...)
  	}
  }
docs: // matchLevel is used to recursively descend into the trie.