Solution to https://gist.github.com/amicojeko/26b6848df19c277cee0b

gistfile1.rb

module HiddenLogger

  def inject_log(method_name)

    instance_exec(method_name) do |method_name|
      def method_name_with_logging
        method_name_without_logging
        puts "Sarcazzo: #{@foo}"
      end

      eval("alias :method_name_without_logging :#{method_name}")
      eval("alias :#{method_name} :method_name_with_logging")

    end

  end

end

class Parent
  include HiddenLogger

  def do_something
    @foo = "bar"
    puts "do_something from parent"
  end

  def initialize
    inject_log :do_something
  end
end

class Child < Parent

  def do_something
    @foo = "baz"
    puts "do_something from child"
  end

end


f = Parent.new
c = Child.new

f.do_something
c.do_something