From: nobu@...
Date: 2006-08-10T17:31:53+09:00
Subject: Re: Why can't I alias_method :remove_method ?

Hi,

At Thu, 10 Aug 2006 15:46:40 +0900,
Pat Maddox wrote in [ruby-talk:207490]:
> irb(main):001:0> class Foo
> irb(main):002:1> alias_method :old_remove_method, :remove_method
> irb(main):003:1> end
> NameError: undefined method `remove_method' for class `Foo'
>         from (irb):2:in `alias_method'
>         from (irb):2
> 
> But you can call remove_method from within the class, so why can't you  
> alias it?  What other methods can't you alias?  Or rather, what are the  
> restrictions/conditions under which you must use alias_method?

You can call a singleton method named remove_method which is
inherited from the super class, Module, but you didn't define
an instance method named remove_method.

You can:

  class Foo
    class << self
      alias_method :old_remove_method, :remove_method
    end
  end

-- 
Nobu Nakada