metaprogramming ruby sample code: using.rb

gistfile1.rb

module Kernel
  def using(resource)
    begin
      yield
    ensure
      resource.dispose
    end
  end

  def using2(resource)
    begin
      yield
    ensure
      resource.dispose
    end
  end
end

class Resource
  def dispose
    @disposed = true
  end

  def disposed?
    @disposed
  end
end

r = Resource.new

# using(r){raise}
#=>  wrong argument type Resource (expected Module) (TypeError)

# using2(r){raise}
#=> `block in <main>': unhandled exception

あ、refinementsか