From: Lyle Johnson <lyle@...>
Date: 2004-02-09T08:53:35+09:00
Subject: Re: ruby and pointers

Elias Athanasopoulos wrote:

> Suppose:
> 
> pool = [1.2, 2.434, 1.132, 1.1334]
> foo = 0.0
> pool.each do |x|
>     foo = x     # foo changes value and actual address in mem
> end
> 
> Can I give foo the value *only* of x but not change its
> actual address in memory?

I don't think so, because foo is a reference to a Float object, and 
Float objects are immutable. In contrast, if foo were a reference to 
some kind of mutable object (like a String), you *could* change its 
value without creating a new object in the process, e.g.

     foo = "a string"
     puts foo.id
     foo.sub!("a", "the")
     puts foo.id # should be the same as before the sub!

Hope this helps,

Lyle