template<class K, class V>
struct map_list_of_type {
  typedef std::map<K, V> Map;
  Map data;
  map_list_of_type(K k, V v) { data[k] = v; }
  map_list_of_type& operator()(K k, V v) { data[k] = v; return *this; }
  operator Map const&() const { return data; }
};
template<class K, class V>
map_list_of_type<K, V> my_map_list_of(K k, V v) {
  return map_list_of_type<K, V>(k, v);
}

int main() {
  std::map<int, char> example = 
    my_map_list_of(1, 'a') (2, 'b') (3, 'c');
  cout << example << '\n';
}

[(1, a), (2, b), (3, c)]