ruby meta programming

core method

define_singleton_method

# defind
module MessagesDictionary
  def self.included(klass)
    klass.class_exec do # valuates some code in the context of some class
      define_singleton_method :has_messages_dictionary do |opts = {}| # define has_messages_dictionary method by define_singleton_method
      end
    end
  end
end
# usage
class MyClass
  include MessagesDictionary # include module
  has_messages_dictionary

  def greet
    pretty_output(:hi) # Prints "Hello there!" in the terminal
  end
end

tutorial

• messages_dictionary gem