From: Robert Evans <robert.evans@...>
Date: 2005-11-15T14:16:54+09:00
Subject: Re: removing a constant definition from an environment

Hey Everybody,

Thanks for your help. I went for Mark's approach of using  
Object.instance_eval(:remove_const, :FOO).

I want to make sure I understand what is going on, so let me know if  
I get the reason this works wrong.

This works because: Object includes Kernel which is a Module, so it  
gets all the methods on Module, which includes remove_const. Is that  
correct?

Thanks,
Bob Evans


On Nov 14, 2005, at 5:44 PM, Mark Hubbart wrote:

> On 11/14/05, Mauricio Fern�ndez <mfp@acm.org> wrote:
>> On Tue, Nov 15, 2005 at 07:16:06AM +0900, Mauricio Fern�ndez wrote:
>>> On Tue, Nov 15, 2005 at 06:56:59AM +0900, Robert Evans wrote:
>>>> Hi Ryan,
>>>>
>>>> Thanks for your help.
>>>>
>>>> I tried that, and it didn't work. Here is my irb transcript trying
>>>> that. Is there another way to remove a constant? I thought I had  
>>>> seen
>>>> one in the Pickaxe book, but maybe I was thinking of the module  
>>>> method.
>>>>
>>>> irb
>>>> irb(main):001:0> FOO = "my symbol value"
>>>> => "my symbol value"
>>>> irb(main):002:0> remove_const(FOO)
>>>> NoMethodError: undefined method `remove_const' for main:Object
>>>>         from (irb):2
>>>> irb(main):003:0> remove_const(:FOO)
>>
>> Sorry, I meant
>>  Object.send(:remove_const, :FOO)
>
> I may be wrong, but I think using #send to bypass private method
> encapsulation is not future-proof. Instead, you might use
>
>   Object.instance_eval{ remove_const :FOO }
>
> This is almost guaranteed to work in the future.
>
> cheers,
> Mark