Issue #4649 has been reported by Rodrigo Rosenfeld Rosas.

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RubySpec #4649: Adding parallel constructors to Ruby 2.0
http://redmine.ruby-lang.org/issues/4649

Author: Rodrigo Rosenfeld Rosas
Status: Open
Priority: Normal
Assignee: Yukihiro Matsumoto
Category: 
Target version: 2.0


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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