class ViewModel::Config

def self._option(opt)
  configure! unless configured?
  @instance[opt]
end

def self.configure!(&block)
  if configured?
    raise ArgumentError.new('ViewModel library already configured')
  end
  builder = KeywordBuilder.create(self, constructor: :with)
  @instance = builder.build!(&block)
end

def self.configured?
  instance_variable_defined?(:@instance)
end