From: "David A. Black" <dblack@...>
Date: 2005-08-12T00:57:12+09:00
Subject: Re: Dynamically changing class methods

Hi --

On Fri, 12 Aug 2005, henrikbrink wrote:

> Hello!
>
> Im making an application that loads and uses the methods of a class
> dynamically. The class can then be altered while the application is
> running, and the application loads the file containing the class every
> time it is needed.
>
> The strange thing is: It works fine when i add a method to the class.
> The new method shows up. But if i remove a method, it acts as if it was
> still there. How can that be?
>
> Here's the code used to get the methods:
>
>    load "#{file}.rb"
>    myclass = Object.const_get "MyClass"
>    myclass_inst = myclass.new
>    methods = myclass_inst.methods

If you do this:

   class MyClass
     def some_method
       # ...
     end
   end

and then, later, do this:

   class MyClass
   end

(i.e., don't define some_method), some_method is still there.  The
effects of opening a class multiple times are cumulative.  This is the
case whether it's all in one file or in multiple files, or even in the
same file loaded multiple times.

If you want to remove a method, you have to use remove_method or
under_method (which are slightly different from each other; see ri or
other docs).

> If I am not clear enough, please ask.

Same here :-)


David

-- 
David A. Black
dblack@wobblini.net