From: Florian Gilcher <flo@...>
Date: 2008-05-24T00:38:51+09:00
Subject: Re: Prevent ruby constant variables from changing?

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On May 23, 2008, at 2:56 PM, Mark Wilden wrote:

> On May 22, 2008, at 11:33 PM, Florian Gilcher wrote:
>
>>>> If you noticed, class names are constants. As you can change  
>>>> classes at runtime, constants must be changable.
>>>> Actually overwriting Constants emits a warning. A you should  
>>>> program warnings-free, that should be no problem :).
>>>
>>> Sure, you can change classes at runtime, but should you be able to  
>>> change which object is referenced by a class name? I haven't heard  
>>> of that before. Do you have a real-world example of someone doing  
>>> that? Just curious.
>>>
>>> ///ark
>>>
>>
>> "Hot code replace" comes to my mind. Completely reloading a class  
>> while keeping the system running. There, it makes sense to  
>> completely obliterate the old class.
>
> You're not really loading a different class - you're just updating  
> the current class, which could be done more tediously by redefining  
> its methods and reinitializing its attributes. But I see what you  
> mean, and you're right.
>
> ///ark
>

"Updating" is a bit of a wild guess in a language where a class can  
change during runtime. I cannot easily "update" a class in ruby as  
there is no good possibility to determine the delta between a class  
and the version you want to update to.

So usually, the practicable approach really is to delete the class an  
completely reload it.

Regards,
Florian Gilcher
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