From: Sean O'Dell <sean@...>
Date: 2004-06-28T06:20:04+09:00
Subject: Re: Is it considered Harmful?

On Sunday 27 June 2004 13:44, Patrick May wrote:
>
> Is the problem that you want to add methods?  Then use Modules.

This is a good question.  In the past, I've wished I could change objects into 
a different state, sort of like taint or freeze, but with a little more 
customization.  For example, taking a File object and replacing all of its 
write methods to custom ones that log everything written.  It can be done by 
adding methods (and removing methods ones you don't want to be available 
anymore), but I thought a really super simple way to handle the situation is 
to simply replace the entire class of the object, so you control 100% what 
methods are available.  That way, if the File object got passed to some other 
method out of your control that called a method you forgot to replace or 
remove, the method wouldn't even be there.

Of course, like I said, the Ruby internals make difficult to make a stable 
feature, so the point is probably moot.  But what I found interesting was how 
easy it was to change an object's class in C, and to provide a fair amount of 
protective code by simply adding a Check_Type call to the R* macros.

>    * #become creates a duplicate lifecycle for objects, resulting in
> lots of complication
>    * It doesn't really add that much functionality

I think if Ruby could handle it with stability, it would simply be another 
possibility.  Some people would find it hard to use, others would find it 
very powerful.  I personally am not afraid of such things; I find myself 
thinking of endless uses for it.

	Sean O'Dell