4 ms·

> is it hard to get the results back out It's trivially easy to get the results, here's a quick example: require "async" require "open-uri" resul

> is it hard to get the results back out It's trivially easy to get the results, here's a quick example: require "async" require "open-uri" results = [] Async do |task| task.async do results << URI.open("https://httpbin.org/delay/1.6") end task.async do results << URI.open("https://httpbin.org/delay/1.6") end end

Spivak 5y ago
I'm not sure if this is the most realistic example since you're implicitly relying on this being at the top level and there being a global await at the end of the block. Surely any real program will have all the work done inside a single top-level event loop. require 'async' Async do results = [] Async do sleep 1 results << "Hello" end puts results # => [] end
- brunosutic 5y ago
  I just ran your example and I'm getting `puts results` line to output "Hello", just as the program intends. I'm not sure why you're getting a different result. In any case, I'm assuring you: getting the results "out of tasks" is trivially easy. > Surely any real program will have all the work done inside a single top-level event loop. I don't get this. Can you please explain more what you have in mind and I'll try to help clarify things.
  - Spivak 5y ago
    Sorry, I needed to add a sleep to get the behavior I wanted. Now it just prints nothing. What I mean is I assume any real program is not going to be creating and destroying event loops any time they want to do something Async and that they'll essentially run main in a top level Async do. In fact it seems like that's the only safe thing to do with this library because the following snippet changes semantics depending on whether it's nested in an existing event loop or not. results = [] Async do sleep 10 results << "Hello" end puts results So it seems like you'll pretty much always have to have an explicit wait before you can get your results in 99% of cases.
    - brunosutic 5y ago
      Wrap the example in a `Sync` block to get deterministic results. Now you don't have to worry if the code gets nested in an existing event loop. Sync do results = [] Async do sleep 10 results << "Hello" end puts results end

Spivak 5y ago

I'm not sure if this is the most realistic example since you're implicitly relying on this being at the top level and there being a global await at the end of the block. Surely any real program will have all the work done inside a single top-level event loop. require 'async' Async do results = [] Async do sleep 1 results << "Hello" end puts results # => [] end

brunosutic 5y ago
I just ran your example and I'm getting `puts results` line to output "Hello", just as the program intends. I'm not sure why you're getting a different result. In any case, I'm assuring you: getting the results "out of tasks" is trivially easy. > Surely any real program will have all the work done inside a single top-level event loop. I don't get this. Can you please explain more what you have in mind and I'll try to help clarify things.
- Spivak 5y ago
  Sorry, I needed to add a sleep to get the behavior I wanted. Now it just prints nothing. What I mean is I assume any real program is not going to be creating and destroying event loops any time they want to do something Async and that they'll essentially run main in a top level Async do. In fact it seems like that's the only safe thing to do with this library because the following snippet changes semantics depending on whether it's nested in an existing event loop or not. results = [] Async do sleep 10 results << "Hello" end puts results So it seems like you'll pretty much always have to have an explicit wait before you can get your results in 99% of cases.
  - brunosutic 5y ago
    Wrap the example in a `Sync` block to get deterministic results. Now you don't have to worry if the code gets nested in an existing event loop. Sync do results = [] Async do sleep 10 results << "Hello" end puts results end