Question

class Foo
  def self.bar
    puts "foobar"
  end

  def bar
    self.class.bar
  end
end

我想避免需要定义实例方法bar。有没有办法自动使类方法作为实例方法可访问？也许有一些method_missing?魔法？

Answer 1

尝试类似：

class Foo

  def self.bar
    puts "foobar"
  end

  def respond_to? name
    super or self.class.respond_to? name
  end

  def method_missing name, *args, &block
    if self.class.respond_to? name
      self.class.send name, *args, &block
    else
      super
    end
  end

end

你也可以这样做（简单版）：

module ChainsToClass
  def respond_to? name
    super or self.class.respond_to? name
  end
  def method_missing name, *args, &block
    if self.class.respond_to? name
      self.class.send name, *args, &block
    else
      super
    end
  end
end

class Foo
  def self.bar
    puts "foobar"
  end
end

Foo.send :include, ChainsToClass

Answer 2

最简单的方法是在子模块中定义方法并将其扩展并包含在类中：

class Foo

  module FooMethods
    def bar
      puts "foobar"
    end
  end

  # Add methods from module FooMethods as class methods to class Foo
  extend FooMethods

  # Add methods from module FooMethods as instance methods to class Foo
  include FooMethods
end

访问类方法，如实例方法

2 个答案: