#include <cassert>
#include <iostream>
#include <iterator>
#include <list>
#include <string>

int main() {
    std::list<std::string> pending{"parse", "compile", "link"};
    std::list<std::string> running{"fetch"};
    auto job = std::next(pending.begin());
    const std::string* address = &*job;
    running.splice(running.end(), pending, job);
    assert(&*job == address && *job == "compile");
    assert((pending == std::list<std::string>{"parse", "link"}));
    assert((running == std::list<std::string>{"fetch", "compile"}));
    running.splice(running.begin(), running, job);
    assert(running.front() == "compile");
    auto next = running.erase(job);
    assert(next != running.end() && *next == "fetch");
    std::cout << pending.size() << ' ' << running.front() << '\n';
}