Question

所以我正在制作一个宝石，我已经有了很好的投入。不幸的是，它有一个非常重要的错误。不幸的是，如果您有一个回调或与该类的public_methods同名的事件，这个gem会创建可以附加回调的事件。这是gem的bug的一个工作示例，其下面有一些测试代码：

# Portion of gem that causes bug
class DemoClass
  def initialize method_symbol
    @method = to_method(method_symbol)
  end

  def call(*args)
    @method.call(*args)
  end

  def some_private_method
    puts 'the private method was called (still bugged)'
  end

  private

  def to_method(method_symbol)
    # this right here references public methods when I don't want it to
    method(method_symbol)
  end
end

# Outside the gem
def some_method
  puts 'this is an original method being called'
end

def some_private_method
  puts 'the private method was NOT called. Bug fixed!'
end

non_bugged_instance = DemoClass.new(:some_method)
bugged_instance = DemoClass.new(:some_private_method)

non_bugged_instance.call
bugged_instance.call

有没有办法让私有方法to_method创建方法对象，其符号:add不引用公共方法add，而是使用方法在那个班级之外？

Answer 1

以下代码演示了通过初始化程序将“main”中定义的方法传递到类中的示例。

class DemoClass
  def initialize method
    @method = method
  end

  def touch *args
    puts 'touch'
    @method.call *args
  end   
end

# Outside the gem
def some_method
  puts 'Unbugged method'
end

def some_private_method
  puts 'Bugged method'
end

non_bugged_instance = DemoClass.new( self.method :some_method )
bugged_instance = DemoClass.new( self.method :some_private_method )

puts "Non bugged touch"
non_bugged_instance.touch

puts "Bugged touch"
bugged_instance.touch

输出：

Non bugged touch
touch
Unbugged method
Bugged touch
touch
Bugged method

如果您强烈希望仅使用方法名称，请使用以下内容替换类初始值设定项：

def initialize method_name
  @method = Kernel.method method_name
end

类创建调用as：

non_bugged_instance = DemoClass.new :some_method
bugged_instance = DemoClass.new :some_private_method

但我真诚地建议使用第一个选项。

Answer 2

好的，显然，为了引用DemoClass之外的方法，我需要使用superclass方法。显然，您还需要引用self.class，否则它将尝试调用名为superclass的公共方法。它们一起看起来像这样：

# Portion of gem that causes bug
class DemoClass
  def initialize method_symbol
    @method = to_method(method_symbol)
  end

  def call(*args)
    @method.call(*args)
  end

  def some_private_method
    puts 'the private method was called (still bugged)'
  end

  private

  def to_method(method_symbol)
    # this right here references superclass methods like it's supposed to
    self.class.superclass.method(method_symbol)
  end
end

# Outside the gem
def some_method
  puts 'this is an original method being called'
end

def some_private_method
  puts 'the private method was NOT called. Bug fixed!'
end

non_bugged_instance = DemoClass.new(:some_method)
bugged_instance = DemoClass.new(:some_private_method)

non_bugged_instance.call
bugged_instance.call

使用方法创建Method对象，同时忽略所有类的public_methods

2 个答案: