configurable.rb

# MyClass.configure { ... } および config_accessor(:name) を提供するモジュール
#
# ```ruby
# class MyClass
#   include Configurable
#   config_accessor :name
# end
#
# MyClass.configure { |config| config.name = 'value' }
# MyClass.new.name # => 'value'
# ```
module Configurable
  extend ActiveSupport::Concern

  class_methods do
    def config_accessor(*names)
      names.each do |name|
        delegate name, "#{name}=", to: :configuration
      end
    end

    def configure
      yield(configuration)
    end

    def configuration
      @configuration ||= ActiveSupport::OrderedOptions.new
    end
  end

  private

  def configuration
    self.class.configuration
  end
end