From: "mame (Yusuke Endoh)" <mame@...>
Date: 2012-06-08T08:41:31+09:00
Subject: [ruby-core:45496] [ruby-trunk - Feature #4649] Adding parallel constructors to Ruby 2.0


Issue #4649 has been updated by mame (Yusuke Endoh).


Received.

You want just Kernel#concurrently and Kernel#task?
And, Kernel#concurrently returns an array that contains the result values returned by inside Kernel#tasks.  Right?
The array may be shuffled, or in the same order as task definitions?

  ary = concurrently do
    task { 1 }
    task { 2 }
    task { 3 }
  end
  p ary #=> [1, 2, 3]

-- 
Yusuke Endoh <mame@tsg.ne.jp>
----------------------------------------
Feature #4649: Adding parallel constructors to Ruby 2.0
https://bugs.ruby-lang.org/issues/4649#change-27084

Author: rosenfeld (Rodrigo Rosenfeld Rosas)
Status: Assigned
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: 
Target version: 


I was not sure if this was RubySpec or Feature type.

My request is to create some new syntax for easing the write of concurrent code with Ruby. The syntax could be something like this:

parallels do
  task "get response from service A" do # optional description
    a = IO.read("http://serviceA/request")
  end
  task { b = get_response_from_service_b }
end

# at this point both tasks have finish, it's like a join in the threads at the end of the parallel block.
call_another_service_that_depends_on(a and b)

I am not sure, though, how to deal with scopes inside the parallel block. Traditionally in Ruby, this wouldn't work because both 'a' and 'b' would be local to the 'task' block and would not be accessible from the outside of the parallel block. If we don't want instance variables, I don't know what is the best approach for avoiding some "a=nil; b=nil" before the parallel block.

Maybe this could start as a gem, but having it implemented directly in Ruby would be awesome, specially for scripts that usually don't rely in external dependencies for simplifying distribution...

Any thoughts about this propose?


-- 
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