Emulates a C# 'using' statement in Ruby

example_usage.rb

require 'kernel_using'

class ResourceConsumer

  def open()
    puts 'Opening up...'
  end

  def close()
    puts 'Closing up...'
  end

  # method for performing clean up
  def cleanup()
    close()
  end

end

using ResourceConsumer.new do |obj|

  obj.open

  # some work
  puts 'Doing work...'

  raise 'Some error...'

  # 'obj' will automatically cleaned up when the block completes 
  # even if an exception occurred

end

kernel_using.rb

module Kernel

  def using(obj, &block)
    begin
      block.call(obj)
    ensure
      obj.cleanup if obj.respond_to? :cleanup
    end
  end

end