just wondering

role_management.rb

require 'test/unit'

module RoleManagement
  @@available_roles ||= []

  def available_roles
    @@available_roles
  end

  def roles
    @roles ||= {}
  end

  def deny(action_name)
    roles[action_name] = false
  end

  def allow(action_name)
    roles[action_name] = true
  end

  def set_role(action_name)
    available_roles << action_name

    class_eval do
      define_method "can_#{action_name}?" do
        !!self.class.roles[action_name]
      end
    end
  end
end

class RoleBase
  extend RoleManagement

  set_role :edit_user
  set_role :create_user
end

class GuestRole < RoleBase
  deny :edit_user
  # deny :create_user => by default is denied
end

class AdminRole < RoleBase
  allow :edit_user
  allow :create_user
end

class GuestRoleTest < Test::Unit::TestCase
  def setup
    @guest = GuestRole.new
  end

  def test_for_default_role
    assert !@guest.can_edit_user?
    assert !@guest.can_create_user?
  end

  def test_for_role_names
    assert_equal @guest.class.available_roles, [:edit_user, :create_user]
  end
end

class AdminRoleTest < Test::Unit::TestCase
  def setup
    @admin = AdminRole.new
  end

  def test_for_default_role
    assert @admin.can_edit_user?
    assert @admin.can_create_user?
  end
end

class User
  def role
    return GuestRole.new
  end
end

p User.new.role.can_create_user?