[Question] What difference between Async and Sync

[Mark24Code]

I wish the document with more examples and details explanation. 😃

[trevorturk]

Likely this should be moved to a Discussion, but a couple quick links that may help explain things:

• https://socketry.github.io/async/guides/best-practices/index#use-a-top-level-sync-to-denote-the-root-of-your-program
• Suggested API change #237

I bet additional documentation would be welcome, if you think that's something you could help with after reading through these docs!

[ioquatix]

• Async{...} returns a promise and executes your code in an event loop.
• Sync{...} returns a value of executing your code in an event loop.

Does this clarify it? We can certainly look at improving the documentation.

[hibachrach]

I think it might help to see how it compares with async/await in other languages. Does Kernel#Sync have a correspondence in JavaScript? From your description it sounds like an await of an immediately invoked promise.

[ioquatix]

Yes, that's correct, e.g. the following Ruby:

Sync{bar()} # returns value of bar()

Is similar to the following JavaScript:

await bar(); // returns value of bar()

And for completeness:

Async{bar()} # returns a promise (task)

Is similar to:

bar(); // returns a promise

There are some minor semantic differences that make Sync a bit more important in Ruby, notably, that without Sync there is no event loop, while in JavaScript the event loop always exists (from process inception). Hope that helps.

[hibachrach]

Honestly, I think a "JS -> Ruby" translation example in the docs would do a lot. JS's async/await (and similar syntaxes in Python, etc.) are fairly ubiquitous. But I also wonder if Sync would be better called AwaitAsync or even remove that as a convenience method and just have only Async and forcing you to call await on it, like how Rust does it.

[ioquatix]

Sync was a joke that became useful, unfortunately hard to change the name now :)

I think improving the documentation is a good idea: #465