thiagoa

module Imageable
  def self.build(methods)
    mod = Module.new do
      methods.each do |method|
        define_method method do
          images.find { |image| image.kind == 'main_image' }
        end
      end
    end

thiagoa

class ModuleFactory < Module
  def initialize
    define_a_method
  end

  private

  def define_a_method
    module_eval do
      def my_method

thiagoa

class Imageable < Module
  def initialize(has_one: %i(main_image))
    has_one.each { |image_kind| define_image_getter(image_kind) }
  end

  private

  def included(model_class)
    model_class.has_many :images
  end

thiagoa

class Project
  include Imageable.new(has_one: %i(main_image secondary_image))
end

project = Project.new
project.main_image #=> <Image kind="main_image" imageable_type="Project">
project.secondary_image #=> <Image kind="secondary_image" imageable_type="Project">

thiagoa

class Imageable < Module
  def initialize(has_one: %i(main_image))
    has_one.each do |image_kind|
      define_method image_kind do
        images.find { |image| image.kind == 'main_image' }
      end
    end
  end

  def included(model_class)

thiagoa

class ModuleGenerator < Module
  def build_methods(methods)
    module_eval do
      methods.each do |method|
        define_method(method) do
          puts "#{method} was defined in the instance methods"
        end
      end
    end
  end

thiagoa

module OneTwoThree
  def one
    puts 'one was defined as an instance method'
  end
  
  def two
    puts 'two was defined as an instance method'
  end
  
  def three

thiagoa

OneTwoThree = Module.new do
  def one
    puts 'one was defined as an instance method'
  end
  
  def two
    puts 'two was defined as an instance method'
  end
  
  def three

thiagoa

class DynamicModuleGenerator < Module
  def initialize(methods)
    module_eval do
      methods.each do |method|
        define_method(method) do
          puts "#{method} was defined as an instance method"
        end
      end
    end
  end

thiagoa

class Module < Object
  def module_eval
    # Only the language has the magic to make this work...
  end
  
  # Imagine there are a bunch of other instance methods here.
  # Module.new generates objects that respond to these methods.
end