如何检查ruby中是否定义了私有方法

Question

我能找到的最接近的是在Ruby中,如何检查方法"foo =()"是否已定义？,但只有当方法是公共的时,它才有效,即使在类块内.

我想要的是:

class Foo
  private

  def bar
    "bar"
  end

  magic_private_method_defined_test_method :bar #=> true
end

我尝试过的:

class Foo
  private

  def bar
    "bar"
  end

  respond_to? :bar #=> false
  #this actually calls respond_to on the class, and so respond_to :superclass gives true
  defined? :bar #=> nil
  instance_methods.include?(:bar) #=> false
  methods.include?(:bar) #=> false
  method_defined?(:bar) #=> false
  def bar
    "redefined!"
  end # redefining doesn't cause an error or anything

  public
  def bar
    "redefined publicly!"
  end #causes no error, behaves no differently whether or not #bar had been defined previously
end

Answer 1

另一种方法是使用:respond_to?,例如

self.respond_to?(:bar, true)

请注意,第二个参数在这里很重要 - 它表示:respond_to?应查找所有范围方法,包括私有方法.

Answer 2

你想要的.Module#private_method_defined?

class Foo
  def do_stuff_if_bar_is_defined
    if self.class.private_method_defined?(:bar)
      do_stuff
    end
  end

  private

  def bar
    "bar"
  end

  private_method_defined? :bar #=> true
end
Foo.private_method_defined? :bar #=> true