From: "Iñaki Baz Castillo" <ibc@...>
Date: 2008-04-25T01:55:30+09:00
Subject: Re: Pointer concept in Ruby ?

2008/4/24, khaines@enigo.com <khaines@enigo.com>:

>  They were the same object, until you pointed a1 at a different object.
>
>  This is the important distinction that you are missing.
>
>  To recap:
>
>  a = [1,2,3,4]
>
>  a points to an Array that contains 4 objects, the Fixnums 1, 2, 3, and 4.
>
>  a[1] calls a method [] on the object pointed to by 'a'.  That method
> returns the object in the 1 position in the array.
>
>  a1 = a[1] points 'a1' at that object.  a1 is just a pointer, though, to an
> object.
>
>  You can't change what the Array pointed to by 'a' contains by pointing 'a1'
> at a different object, which is what your assignment of "NEW STRING" to 'a1'
> did.
>
>  If you want to change what is stored in the 1 index position in the Array
> pointed to by 'a', you need to be operating on that Array.
>
>  b = a
>  b[1] = "another new string"
>  puts a[1]
>
>  another new string
>
>
>  Make sense?


Sure, but I already kwen it, note that I was answering to Mikael that said:

> If you however call a self-modifying method on a1 while it's pointing at the array string, it'll also
> change in the array, as it's still pointing at the same object.


But thanks for the explanation :)


-- 
Iñaki Baz Castillo
<ibc@aliax.net>