returning_self.rb

class Object
  define_method :returning_self do
    ReturningSelf.new(self)
  end
  class ReturningSelf
    private *instance_methods.select { |m| m !~ /(^__|^\W|^binding$)/ }
    def initialize(subject)
      @subject = subject
    end
    def method_missing(sym, *args, &blk)
      @subject.send(sym,*args,&blk)
      @subject
    end
  end
end

# [1,2].compact!
# => nil
# [1,2].returning_self.compact!
# => [1, 2]