unordered_map_gen.cpp

template<class RollCountGenerator, class KeyGenerator, class ValueGenerator>
auto unordered_map_gen(RollCountGenerator roll_count_gen,
                       KeyGenerator key_gen,
                       ValueGenerator value_gen)
{
   return [=](std::mt19937& bit_gen)
   {
      int count = roll_count_gen(bit_gen);
      std::unordered_map<decltype(key_gen(bit_gen))
                        ,decltype(value_gen(bit_gen))> out;
      out.reserve(count);
      details::repeat_n_gen(std::inserter(out, out.end()),
                            count, pair_gen(key_gen, value_gen), bit_gen);
      return out;
   };
}

template<typename KeyGenerator, typename ValueGenerator>
auto unordered_map_gen(int max_rolls,
                       KeyGenerator key_gen,
                       ValueGenerator value_gen)
{
   return unordered_map_gen(int_gen(0, max_rolls), key_gen, value_gen);
}