ruby – 如何使用define_method定义？(超级)

请参阅下面的示例.请注意,即使已定义,super(value)也是有效的调用？不这么认为.

class A
  def message=(val)
    puts 'A says ' + val
  end
end

class B < A
  ['message','warning'].each do |method|
    define_method(method + '=') do |val|
      puts 'B says ' + val
      super(val) if defined?(super)
    end
  end
end

a = A.new
a.message = 'hello!' # A says hello!
b = B.new
b.message = 'hello!' # B says hello!

############################################

class B < A
  ['message','warning'].each do |method|
    define_method(method + '=') do |val|
      puts 'B says ' + val
      super(val) rescue nil
    end
  end
end

b = B.new
b.message = 'hello!' # B says hello! A says hello!