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執行個體公開方法

config()

來源：顯示 | 在 GitHub 上 

# File activesupport/lib/active_support/configurable.rb, line 30
def config
  @_config ||= if respond_to?(:superclass) && superclass.respond_to?(:config)
    superclass.config.inheritable_copy
  else
    # create a new "anonymous" class that will host the compiled reader methods
    Class.new(Configuration).new
  end
end

configure()

來源：顯示 | 在 GitHub 上 

# File activesupport/lib/active_support/configurable.rb, line 39
def configure
  yield config
end

執行個體私有方法

config_accessor(*names, instance_reader: true, instance_writer: true, instance_accessor: true, default: nil)

允許您新增捷徑，這樣您就不必透過 config 參照屬性。此外，請參閱 config 的範例以做對比。

定義類別和執行個體 config 存取器。

class User
  include ActiveSupport::Configurable
  config_accessor :allowed_access
end

User.allowed_access # => nil
User.allowed_access = false
User.allowed_access # => false

user = User.new
user.allowed_access # => false
user.allowed_access = true
user.allowed_access # => true

User.allowed_access # => false

屬性名稱必須是 Ruby 中有效的函式名稱。

class User
  include ActiveSupport::Configurable
  config_accessor :"1_Badname"
end
# => NameError: invalid config attribute name

若要略過執行個體寫入函式，請傳遞 instance_writer: false。若要略過執行個體讀取函式，請傳遞 instance_reader: false。

class User
  include ActiveSupport::Configurable
  config_accessor :allowed_access, instance_reader: false, instance_writer: false
end

User.allowed_access = false
User.allowed_access # => false

User.new.allowed_access = true # => NoMethodError
User.new.allowed_access        # => NoMethodError

或者傳遞 instance_accessor: false，以略過兩個執行個體函式。

class User
  include ActiveSupport::Configurable
  config_accessor :allowed_access, instance_accessor: false
end

User.allowed_access = false
User.allowed_access # => false

User.new.allowed_access = true # => NoMethodError
User.new.allowed_access        # => NoMethodError

您也可以傳遞 default 或區塊，以設定具有預設值的屬性。

class User
  include ActiveSupport::Configurable
  config_accessor :allowed_access, default: false
  config_accessor :hair_colors do
    [:brown, :black, :blonde, :red]
  end
end

User.allowed_access # => false
User.hair_colors # => [:brown, :black, :blonde, :red]

來源：顯示 | 在 GitHub 上 

# File activesupport/lib/active_support/configurable.rb, line 111
def config_accessor(*names, instance_reader: true, instance_writer: true, instance_accessor: true, default: nil) # :doc:
  names.each do |name|
    raise NameError.new("invalid config attribute name") unless /\A[_A-Za-z]\w*\z/.match?(name)

    reader, reader_line = "def #{name}; config.#{name}; end", __LINE__
    writer, writer_line = "def #{name}=(value); config.#{name} = value; end", __LINE__

    singleton_class.class_eval reader, __FILE__, reader_line
    singleton_class.class_eval writer, __FILE__, writer_line

    if instance_accessor
      class_eval reader, __FILE__, reader_line if instance_reader
      class_eval writer, __FILE__, writer_line if instance_writer
    end

    send("#{name}=", block_given? ? yield : default)
  end
end