From: "François Montel" <zerohalo@...>
Date: 2007-04-05T07:12:17+09:00
Subject: Re: nil? and non-existent objects

Jamal Soueidan wrote:

> You could also fix it this way :)
> 
> ----------------------------------------------
> 
> def x
>   @x
> end
> 
> def x=(val)
>    @x = val
> end
> 
> puts x=1 if x.nil?
> 
> ----------------------------------------------
> 
> This would output: 1

Actually, it needs no fixing, or the def statements. The explanation 
(thanks, Brian, et al) is that "x=1 if x.nil?" works because when the 
parser sees 'x=1' it flags x as a local variable and creates it, 
assigning it the value nil. Only then does it execute x.nil?, which 
returns a value since x now exists.

In other words, if there is any reference to a new local variable in 
your code, even if that reference is not executed (as in Brian's 
example), the local variable is created and assigned a nil value.

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