From: Robert Klemme <shortcutter@...>
Date: 2008-09-27T23:14:36+09:00
Subject: Re: Does array's each-block destroies outer objects ?

On 27.09.2008 11:14, Sebastian Hungerecker wrote:
> w wg wrote:
>> After execute the block , it looks like that ruby destroied the former
>> 'x' object,

There is no object destroyed.  The variable x is made to point to 
another object.  If there are no more references to the object pointed 
to by x before it can be garbage collected at any point in time after x 
has been made to point to another instance.

> the 'x' object has object_id 4 now, which is same as
>> a[4].object_id.
> 
> Yes, if you do {|foo|...} and you have a local variable foo outside the block,
> then the outer foo will be replaced by the value that is yielded to the block.
> This is a property of blocks in 1.8, not of each in particular. This behaviour 
> will no longer be present in 1.9.
> 
>> If so , does it mean that I must choose another variable name in
>> array's each block to keep the 'x' object alive ?
> 
> Yes.

Just to throw in the keyword for the concept involved to help in further 
research of the matter: the concept is called "scoping" - the scoping 
rules for a programming language determine which variables are visible 
in which program artifacts (blocks, methods...) and especially what 
happens to variables with identical names.

Kind regards

	robert