9.2. Async/await coroutine macros

The ASYNC_BOOST module implements an async/await pattern for daslang using channels and coroutines. It provides async for launching concurrent tasks and await for waiting on their results, built on top of the job queue infrastructure.

All functions and symbols are in “async_boost” module, use require to get access to it.

require daslib/async_boost

9.2.1. Function annotations

async_boost.AwaitMacro

Function annotation that implements coroutine await semantics.

async_boost.AwaitCoroutineMacro

This macro converts await(<coroutine>) expression into:

for t in THAT
    yield t

The idea is that coroutine or generator can continuously yield from another sub-coroutine or generator.

async_boost.async

This macro converts function into generator. Generator yields bool if its a void function (coroutine), and yields the return type otherwise (async return). async function can wait for another async function using await(<async fn call>). use ‘return false’ to immediately return from the generator.

9.2.2. Awaiting

• await (var a: iterator<bool>) : bool

• await (var a: iterator<variant<res:auto(T);wait:bool>>) : T

• await_next_frame ()

9.2.2.1. await

async_boost.await(a: iterator<bool>): bool

This function is used to wait for the result of the async function.

Arguments:

• a : iterator<bool>

async_boost.await(a: iterator<variant<res:auto(T);wait:bool>>): T

---

async_boost.await_next_frame()

This function is used to suspend coroutine until next frame.

9.2.3. Running async tasks

• async_run (var a: iterator<auto>) : auto

• async_run_all (var a: array<iterator<auto>>) : auto

async_boost.async_run(a: iterator<auto>): auto

This function runs async function until it is finished.

Arguments:

• a : iterator<auto>

async_boost.async_run_all(a: array<iterator<auto>>): auto

This function runs all async function until they are finished (in parallel, starting from the last one).

Arguments:

• a : array<iterator<auto>>