如何将Ruby中调用Singleton实例方法的DRY类方法改写成长尾词？

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在Ruby中调用Singleton类的实例方法时，不需要直接引用实例。例如，对于名为`ExchangeRegistry`的Singleton类，可以直接使用`ExchangeRegistry.instance.method_name`来调用其方法，而不需要`instance`关键字。例如：

ExchangeRegistry.instance.exchanges

参见英文答案 > Calling a method of a Ruby Singleton without the reference of ‘instance’5个
我有一个Singleton类ExchangeRegistry,它保存所有Exchange对象.

而不是需要打电话：
ExchangeRegistry.instance.exchanges

我希望能够使用：
ExchangeRegistry.exchanges

这有效,但我对重复不满意：

require 'singleton' # Ensure an Exchange is only created once class ExchangeRegistry include Singleton # Class Methods ###### Here be duplication and dragons def self.exchanges instance.exchanges end def self.get(exchange) instance.get(exchange) end # Instance Methods attr_reader :exchanges def initialize @exchanges = {} # Stores every Exchange created end def get(exchange) @exchanges[Exchange.to_sym exchange] ||= Exchange.create(exchange) end end

我对类方法中的重复感到不满意.

我已经尝试过使用Forwardable和SimpleDelegator,但似乎无法让它干掉. (大多数示例都不是类方法,而是例如方法)

可转发模块将执行此操作.由于您要转发类方法,您必须打开特征类并在那里定义转发：

require 'forwardable' require 'singleton' class Foo include Singleton class << self extend Forwardable def_delegators :instance, :foo, :bar end def foo 'foo' end def bar 'bar' end end p Foo.foo # => "foo" p Foo.bar # => "bar"