From: Charlie <peckcharlie@...>
Date: 2006-04-30T15:57:41+09:00
Subject: Re: Constant in Ruby.

Mike Fletcher wrote:
> Charlie wrote:
>> I'm new to Ruby programming and I saw this article which concerns me:
>> 
>> http://www.bitwisemag.com/copy/features/opinion/ruby/ruby_debate.html
>> 
>> Don't get me wrong, I love Ruby. But, the idea that a constant is not a 
>> constant is worrying isn't it? Or have I missed something? Please 
>> comment.
>> 
>> X = 10
>> Y = "hello world"
>> Z = "hello world"
>> 
>> X = 20
>> Y = "byebye" << "abc"
>> myvar = Z << "xyz"
>> 
>> puts(X)
>> 20
>> puts(Y)
>> byebyeabc
>> puts(Z)
>> hello worldxyz
>> myvar
>> "hello worldxyz"
> 
> It's constant in that you can't reassign a different instance to the 
> same name (try setting X = 10 after you've set it to 20 and Ruby will 
> gripe).  The instances themselves may still be mutable (see 
> Object#freeze if you want to change that).

okay, I just try this:

X = 20
X = 10
puts(X)
10
X.freeze
X = 30
puts(X)
30

   Sorry, but I find it difficult to understand as I'm new to it. Would 
be helpful if you can enlighten me with some examples. Thanks.




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