code: func (s *Shape) MemberNames() []string {
  	i, names := 0, make([]string, len(s.MemberRefs))
  	for n := range s.MemberRefs {
  		names[i] = n
  		i++
  	}
  	sort.Strings(names)
  	return names
  }
docs: // MemberNames returns a slice of struct member names.