md_docs_2test__cases_2t00069.html

#include <coroutine>

#include <optional>


namespace clanguml {

namespace t00069 {


template <typename T> struct generator {

    struct promise_type;

    using handle_type = std::coroutine_handle<promise_type>;


    generator(handle_type h)

        : h_(h)

    {

    }


    ~generator() { h_.destroy(); }


    struct promise_type {

        T value_;

        std::exception_ptr exception_;


        generator get_return_object()

        {

            return generator(handle_type::from_promise(*this));

        }

        std::suspend_always initial_suspend() { return {}; }


        std::suspend_always final_suspend() noexcept { return {}; }


        void unhandled_exception() { exception_ = std::current_exception(); }


        template <std::convertible_to<T> From>

        std::suspend_always yield_value(From &&from)

        {

            value_ = std::forward<From>(from);

            return {};

        }


        void return_void() { }

    };


    handle_type h_;


private:

    bool full_ = false;

};


class A {

public:

    generator<unsigned long> iota() { co_yield counter_++; }


    generator<unsigned long> seed()

    {

        counter_ = 42;

        co_return;

    }


private:

    unsigned long counter_;

};


} // namespace t00069

} // namespace clanguml