From: Ryan Paul <segphault@...>
Date: 2004-05-15T17:18:50+09:00
Subject: Re: changing class at runtime

Very cool! Thanks!! In addition to be exactly what I wanted, Its also a
beautiful example of some advanced ruby techniques.

On Sat, 15 May 2004 17:03:15 +0900, Mauricio Fern�ndez wrote:

> On Sat, May 15, 2004 at 04:48:54PM +0900, Ryan Paul wrote:
>> I'm trying to find a way to arbitrarily alter the class of an instance at
>> runtime. The documentation didn't appear to have any clues.
>> 
>> Ultimately, I want to be able to do something like this:
>> 
>> class MyClass1
>>   def fnc1
>>     puts "fnc1 in class 1"
>>   end
>> end
>> 
>> class MyClass2
>>   def fnc1
>>     puts "fnc1 in class 2"
>>   end
>> end
>> 
>> a = MyClass1.new
>> a.fnc1
>> puts a.class
>> 
>> a.class = MyClass2
>> a.fnc2
>> puts a.class
>> 
>> Python lets you do it thusly: someinstance.__class__ = someclass
> 
> batsman@tux-chan:/tmp$ cat ghfgkhjioujklg.rb
> require 'evil'
> 
> class MyClass1
>   def fnc1
>     puts "fnc1 in class 1"
>   end
> end
> 
> class MyClass2
>   def fnc1
>     puts "fnc1 in class 2"
>   end
> end
> 
> a = MyClass1.new
> a.fnc1
> puts a.class
> 
> a.class = MyClass2
> a.fnc1
> puts a.class
> 
> batsman@tux-chan:/tmp$ ruby ghfgkhjioujklg.rb
> /home/batsman/usr/lib/ruby/1.8/dl/import.rb:12: warning: instance variable @types not initialized
> fnc1 in class 1
> MyClass1
> fnc1 in class 2
> MyClass2
> 
> 
> http://evil.rubyforge.org