我如何在Ruby中捕获方法的调用

Question

I want to trap invocation of a method and then display output.

class A 

end

If i run new A.see it should trap and print 'unkown method'.

I am new to the language

Answer 1

When you send a message to an object, the object executes the first method it finds on its method lookup path with the same name as the message. If it fails to find any such method, it raises a NoMethodError exception, unless you have provided the object with a method called method_missing . The method_missing method is passed the symbol of the non-existent method, an array of the arguments that were passed in the original call and any block passed to the original method.

class A 
  def method_missing(m, *args, &block)  
    puts "There's no method called #{m} here -- please try again."  
    super
  end  
end

Answer 2

这已经触发了NoMethodError，默认情况下会暂停程序。

NoMethodError: undefined method `see' for A:Class