From: Chris Hulan <chris.hulan@...>
Date: 2010-04-20T23:20:09+09:00
Subject: Re: Is there a way to make class and object constants in Ruby?

To make objects immutable you can 'freeze' them.  After being frozen
any attempt
to change will result in an error:
>> x = 'test'
=>
"test"
>> x.freeze
=>
"test"
>> x[0] = 'w'
RuntimeError: can't modify frozen string