Decorator for Ruby similar to Python's decorator

decorator.rb

module Decorator
  @@decorators = []
  def decorate(method_name,*args)
    @@decorators << [method_name.to_sym,args]
  end
  def method_added(method_name)
    super
    return if @@decorators.empty?
    decorators = @@decorators.reverse.map{|name,args| [method(name),args]}
    @@decorators = []
    method = instance_method(method_name)
    define_method(method_name) do |*args|
      decorators.inject(method.bind(self)){|m,d| d[0].call(*d[1],&m)}.call(*args)
    end
  end
end

require 'benchmark'

module SampleDecorator
  include Decorator

  def print_args
    lambda{|*args|
      printf "args = (%s)\n", args.map{|x| x.inspect}.join(',')
      yield(*args)
    }
  end

  def measure(label:nil)
    lambda{|*args|
      a = nil
      Benchmark.bm do |x|
        x.report(label){ a = yield(*args) }
      end
      a
    }
  end
end

class Test
  extend SampleDecorator
  decorate :print_args
  decorate :measure,label:"mul"
  def mul(a,b)
    a * b
  end
end

t = Test.new
p t.mul(3,4)

=begin
$ ruby decorator.rb 
args = (3,4)
       user     system      total        real
mul  0.000009   0.000001   0.000010 (  0.000004)
12
=end