From: Jack Christensen <jack@...>
Date: 2005-12-29T14:01:58+09:00
Subject: Re: Locking classes?

Max Eskin wrote:

>Hi,
>I am just starting to use Ruby. I'm wondering, once a class has been 
>declared, is there any way to lock it to prevent further methods from 
>being defined? In other words is there a way to make Ruby act like a 
>static language for some classes?
>
>  
>
freeze the class. Example:

irb(main):001:0> class A
irb(main):002:1> def f
irb(main):003:2> 42
irb(main):004:2> end
irb(main):005:1> end
=> nil
irb(main):006:0> A.freeze
=> A
irb(main):007:0> class A
irb(main):008:1> def g
irb(main):009:2> 43
irb(main):010:2> end
irb(main):011:1> end
TypeError: can't modify frozen class
        from (irb):8


Jack