ruby prototyping

prototype.rb

# Manage user email subscriptions and opt-outs.
module OptOut
  def config
    @config ||= Configuration.new
  end

  def configure(&blk)
    blk.call(config) if blk
    config
  end
  module_function :config, :configure

  class Configuration < Struct.new(:user, :persistence)
  end

  module Persistence
    class AbstractAdapter

    end

    class MemoryAdapter < AbstractAdapter
    end
  end

  class Unsubscription
  end

  class List
    # Public: lookup a list by name
    #
    # Returns a List instance
    def self.[](name)
      new(name)
    end

    attr_accessor :name

    def initialize(name)
      @name = name
    end

    def subscribe(user)
    end

    def unsubscribe(user)
    end

    def subscribers
    end

    def subscribed?(user)
    end
  end

  # Defaults
  configure do |c|
    c.persistence = OptOut::Persistence::MemoryAdapter
    c.user = {
      :primary_key => Proc.new {|u| u.id}
    }
  end

  class ListTest < Test::Unit::TestCase
    def setup
      @list = List['security']
    end

    def test_lookup
      assert @list.is_a?(List)
      assert_equal 'security', @list.name
    end

    def test_subscribe
      @list.subscribe()
    end
  end
end

You can turn

def configure(&blk)
    blk.call(config) if blk
    config
  end

into

def configure
    yield(config) if blk
    config
end

I believe.

Although now that I think about it, if you instance_eval the block will have access to config and you wont have to bother with a block argument.

Psst, @krainboltgreene, there's no blk variable now. I think you want block_given?

yield if block_given?

personally I prefer explicit blocks

and definitely prefer a basic block call to instance_eval !!

but yes ruby is super nice for composing ideas simply and quickly