An example demonstrating the block configuration pattern in Ruby.

configuration_example.rb

require 'singleton'

# The gem's main module.
module AwesomeGem
  # A class method which yields the configuration to a block.
  def self.configure
    yield Configuration.instance if block_given?
  end

  # A class method to access the configuration instance.
  def self.configuration
    Configuration.instance
  end

  # Our gem's configuration class, includin Ruby's singleton model.
  class Configuration
    include Singleton

    # The list of configuration options our module will have.
    CONFIG_OPTIONS = [:do_magic, :awesome_string]

    attr_writer(*CONFIG_OPTIONS)

    # Accessor methods for the options.
    def do_magic?
      @do_magic 
    end

    def awesome_string
      @awesome_string
    end
  end
end