life_string_view.cpp

#include <string_view>
#include <memory>
#include <utility>

class life_string_view {
  std::string_view _data;
  std::shared_ptr<void> _life;
public:
  life_string_view(std::string_view sv)
    : _data{sv}, _life{} {}
  life_string_view(std::string_view sv, std::shared_ptr<void> life)
    : _data{sv}, _life{life} {}

  template <class T>
  static life_string_view allocate(T&& data) {
    auto p = std::make_shared<T>(std::forward<T>(data));
    return {*p, p};
  }

  life_string_view substr(std::size_t start, std::size_t size) {
    return {_data.substr(start, size), _life};
  }

  friend std::ostream& operator<<(std::ostream& os, life_string_view sv) {
    return os << sv._data;
  }
};

#include <iostream>
life_string_view f(life_string_view sv)
{
  return sv.substr(1, 3);
}

life_string_view g() {
  std::string s = "Hello";
  return f(life_string_view::allocate(std::move(s)));
}

int main() {
  auto sv = g();
  std::cout << sv << std::endl;
}