3 ms·

What about async/await? It seems to be a safe pattern under the criteria stated in the article as long as all async calls are awaited. This pattern guarantees

What about async/await? It seems to be a safe pattern under the criteria stated in the article as long as all async calls are awaited. This pattern guarantees the flow will return back only after all async task have finished. The article says modern languages allow domesticated forms of goto (statements like break, continue, return...) that are scoped at function level. What about exceptions and exception handling? An exception thrown in a function and caught in a parent works as a wild goto. The railway pattern comes to my mind.

masklinn 4y ago
> What about async/await? > It seems to be a safe pattern under the criteria stated in the article as long as all async calls are awaited. Which means it's not unless that awaiting is mandatory in all cases. Which it is not because pretty much all such systems have a `spawn`-type construct (when it's not the plain default as it is in Javascript, or C# IIRC) which just forks off an independent task. Your `await` acts as a `join`, but that's still just a join, which is optional, and which most systems have (except go, because goroutines don't have handles). The argument of structured concurrency is the binding of mandatory joining (or awaiting) to the lexical scope, in the way structured flow bound jumps to lexical scopes.
conradludgate 4y ago
Async await is a different concept to structured concurrency. It just allows that two async tasks can run on the same work thread, but it doesn't directly give you access to do so. That's what goroutines, task spawn methods or structured concurrency give you. At least in rust, calling an async function won't do anything by itself. It must be spawned or awaited. However, I wouldn't be surprised if other languages spawned on every async call and the await was just a join handle.

3 ms·

What about async/await? It seems to be a safe pattern under the criteria stated in the article as long as all async calls are awaited. This pattern guarantees

by javitury 4y ago

masklinn 4y ago
> What about async/await? > It seems to be a safe pattern under the criteria stated in the article as long as all async calls are awaited. Which means it's not unless that awaiting is mandatory in all cases. Which it is not because pretty much all such systems have a `spawn`-type construct (when it's not the plain default as it is in Javascript, or C# IIRC) which just forks off an independent task. Your `await` acts as a `join`, but that's still just a join, which is optional, and which most systems have (except go, because goroutines don't have handles). The argument of structured concurrency is the binding of mandatory joining (or awaiting) to the lexical scope, in the way structured flow bound jumps to lexical scopes.
conradludgate 4y ago
Async await is a different concept to structured concurrency. It just allows that two async tasks can run on the same work thread, but it doesn't directly give you access to do so. That's what goroutines, task spawn methods or structured concurrency give you. At least in rust, calling an async function won't do anything by itself. It must be spawned or awaited. However, I wouldn't be surprised if other languages spawned on every async call and the await was just a join handle.