From: Martin DeMello <martindemello@...>
Date: 2008-08-20T08:26:57+09:00
Subject: Re: Nested Arrays in Method Definitions--a puzzle

On Tue, Aug 19, 2008 at 4:16 PM, Jonah Bloch-Johnson
<jsb2142@columbia.edu> wrote:
>
>  def haves
>        x = [1]
>        y = []
>        y << x
>        x = [2] # (compare this)
>        y
>  end
>
> Why does meddling with the innards of the "x" have retroactive
> repercussions, whereas redefining it outright does not?

When you say 'x = [2]' you aren't redefining the object x, you are
taking the variable 'x' and binding it to a new object. When you say y
<< x, you are inserting the object that x was pointing to at that
moment into y, not the variable x. Think of a variable as an alias for
an object - what is actually passed around are the objects themselves,
but you can refer to them by any of their current aliases.

martin