SYNOPSIS

Provides coroutine-based async/await and minimal promises.

ASYNC/AWAIT

USAGE

• Any function that returns an Async<T> type becomes a coroutine.
• Use co_return instead of return for coroutines.
• Only coroutines can use co_await, and only coroutines are awaitable.
• Awaitable functions have a get method to retrieve the value from the promise.

EXAMPLE

auto answer = []() -> Async<int> {
  //
  // ...possibly do something async here,
  // this could also be a regular function.
  //
  co_return 42;
};

auto question = []() -> Async<int> {
  //
  // await the promise created by the answer function.
  //
  auto n = co_await answer();

  //
  // use co_return instead of return!
  //
  co_return n;
};

auto v = question().get(); // v == 42

Refer to this paper for specifics about coroutines in C++.

PROMISE

Promise<int> p;
Timeout timeout;

timeout.start([&] {
  p.resolve(42);
}, 512);

auto v = p.await(); // blocks until resolved is called.