round table - Blocks

class Configuration
  attr_accessor :tail_logs, :max_connections, :admin_password, :app_server

  def app_server
    @app_server ||= AppServerConfiguration.new
    if block_given?
      yield(@app_server)
    end
    @app_server
  end
end

class AppServerConfiguration
  attr_accessor :port, :admin_password
end
  
def configure
  configuration = Configuration.new
  yield(configuration)
  configuration
end

configuration = configure do |config|
  config.tail_logs = true
  config.max_connections = 55
  config.admin_password = 'secret'
  config.app_server do |app_server_config|
    app_server_config.port = 8808
    app_server_config.admin_password = config.admin_password
  end
end

p configuration.class # => Configuration
p configuration.tail_logs # => true
p configuration.app_server.admin_password # => 'secret'