shared hm hm

class Task;

struct Step
{
    Step(Task *task)
    {
        ptask = task;
    }
    virtual bool exec() = 0;

private:
    Task *ptask = nullptr;
}

struct Task_End : public Step
{
    bool exec() override
    {
        if (!ptask)
            return false;
        if (ptask->steps.empty())
            return false;
        if (ptask->steps.back().get() != this)
            return false;

        auto ptr = ptask->steps.back();

        ptasks->steps.clear();
        return true;
    }
}

class Task
{
public:
    Task()
    {
        steps.push_back(std::make_shared<Task_End>(this));
    }

private:
    std::vector<std::shared_ptr<Step>> steps;
}