require 'adapter'
require 'yaml'
Adapter.define(:optional_yaml_memory) do
  def read(key)
    decode(client[key])
  end
  def write(key, value)
    client[key] = encode(value)
  end
  def delete(key)
    client.delete(key)
  end
  def clear
    client.clear
  end
  
  def encode(value)
    if options[:yaml]
      YAML.dump(value)
    else
      value
    end
  end
  
  def decode(value)
    if value && options[:yaml]
      YAML.load(value)
    else
      value
    end
  end
end
yaml_adapter = Adapter[:optional_yaml_memory].new({}, :yaml => true)
yaml_adapter.write('foo', [1, 2, 3])
puts yaml_adapter.client['foo'].inspect  # "--- \n- 1\n- 2\n- 3\n"
puts yaml_adapter.read('foo').inspect    # [1, 2, 3]
adapter = Adapter[:optional_yaml_memory].new({})
adapter.write('foo', [1, 2, 3])
puts adapter.client['foo'].inspect  # "\004\b[\bi\006i\ai\b"
puts adapter.read('foo').inspect    # [1, 2, 3]