Comment by divan | Hacker News Reader

Comment by divan | Hacker News Reader

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It might also come from the common sense of using the CSP model (goroutines and messages, basically). Being asynchronous or synchronous is not the property of the function; it's the caller's decision. So every function is "synchronous" and it's up to the caller to decide when to spin it into the background and what for.

As others commented, it doesn't preclude from you using goroutines in libraries if you _really need to_. It is just important to remember that it's not obvious to the caller.

In light of this "common sense", async/await concurrency concept doesn't make any sense. Why would function dictate how exactly it should be called by a caller? Is "watching TV" an async or sync action? Depends on the caller – whether they put all their attention into this action or doing it "in the background" while performing other tasks. It's not an inherent property of the "whatching TV" function. I have no idea why so many people think that async/await is a good idea for expressing concurrent systems.

I've always seen this as the exact opposite view - from go's concurrency model, every function is "synchronous" so the caller is not given a choice, if they want to run it asynchronously they have to create a new thread, then if they care about the result deal with inter-thread communication.

With async/await, you're explicitly giving control to the caller to decide, you can await this promise now and have the thread treat it as synchronous, you can spawn a new task to run it in the background, or you can join it with other promises where you don't care about order and await for the results of the group.

Interesting. I see two different aspects here:

1) Mental model. My claim comes from the firm belief that the more code is aligned with how we think, the easier it is to reason about the code. I naturally think about actions as they are not async or sync by nature – rather, it's me who's in charge of how the action is going to be executed (back to my "watching TV" example). Human attention here serves as an analogy to utilizing the logical CPU core during runtime.

2) Performance consideration. What you described indeed can work, too, but it comes at a cost. With Go, yes, you have to handle async results yourself (if you care about results), but you now understand the price of this and can make better judgments of the code and complexity and have better performance overall.

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