From: "ko1 (Koichi Sasada)" <redmine@...>
Date: 2012-07-04T13:51:14+09:00
Subject: [ruby-dev:45910] [ruby-trunk - Bug #6694][Open] Thread.new without block.


Issue #6694 has been reported by ko1 (Koichi Sasada).

----------------------------------------
Bug #6694: Thread.new without block.
https://bugs.ruby-lang.org/issues/6694

Author: ko1 (Koichi Sasada)
Status: Open
Priority: Normal
Assignee: ko1 (Koichi Sasada)
Category: core
Target version: 2.0.0
ruby -v: 2.0


=begin
= Abstract

Support Thread.new() without block.

Before: Thread.new(params...){|thread_local_params| ...}

After: Thread.new(proc: lambda{|tl_params...| ...}, args: params..., other_thread_config...)

= Background

Thread.new creates new Thread object and run passed block in another thread immediately.  Thread.new can receive parameters and pass all parameters to block.

  Thread.new(a, b, c) do |ta, tb, tc|
    # ta, tb, tc is thread local
  }

There are some request to specify thread configurations such as stack size described in [Ruby 1.9 - Feature #3187] (in this case, stack size for Fiber.new).  However, we have no way to pass such thread configuration on the Thread.new().

= Proposal

Allow Thread.new() without block.  A block will be passed with proc parameter.  Passed arguments will be passed with args parameter.

  # ex1
  Thread.new(){...}
  #=>
  Thread.new(proc: -> {...})
  
  # ex2
  Thread.new(a, b, c){|ta, tb, tc| ...}
  #=>
  Thread.new(proc: ->(ta, tb, tc){ ... }, params: [a, b, c])

If you want to specify stack size, then:

  Thread.new(stack_size: 4096, proc: proc{...}, args: [a, b, c])

Note that I'll make another ticket for thread (and fiber) creation parameters.

This change can be described with the following pseudo code:

  def Thread.new(*args, &block)
    if block
      Thread.new_orig(*args, &block)
    else
      config = args[0] || raise ArgumentError
      stack_size = config[:stack_size]
      # ... and process another parameters 
      Thread.new_orig(*config[:args], &config[:proc])
    end
  end

= Another proposal

On the [ruby-core:43385], Nahi-san proposed that if no block given on Thread.new(), then create "waiting" thread.  Thread#run kicks waiting thread with parameters.

  th = Thread.new(thread_config_params)
  ...
  th.run(params){|thread_local_params|
    ...
  }

We can combine with proc: parameter and this proposal.  If Thread.new() doesn't have block and proc: parameter, then making a waiting thread.

NOTE: Because we have already Thread#run, Thread#start is better than Thread#run?


= Note

I don't make any survey on other languages.  Please give us your comments.

=end



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