From: Brian Candler <B.Candler@...>
Date: 2008-09-03T22:16:27+09:00
Subject: Re: Open4 : undefined method `spawn'

> seems strange to me because the method spawn IS defined in the "module
> Open4" (lines 241-320)

"include Mod" gives you access to the instance methods of the module, but
not module methods. See http://www.ruby-doc.org/core/classes/Module.html

  irb(main):001:0> module Foo; def test1; puts "hello"; end; end
  => nil
  irb(main):002:0> module Bar; def self.test2; puts "bye"; end; end
  => nil
  irb(main):003:0> include Foo
  => Object
  irb(main):004:0> include Bar
  => Object
  irb(main):005:0> test1
  hello
  => nil
  irb(main):006:0> test2
  NameError: undefined local variable or method `test2' for main:Object
          from (irb):6
          from :0
  irb(main):007:0> Bar.test2
  bye
  => nil

So I haven't tried the Open4 gem, but probably you need "Open4.spawn"

Regards,

Brian.