From: Zev Blut <rubyzbibd@...>
Date: 2005-06-09T22:13:38+09:00
Subject: Re: binding, ObjectSpace._id2ref [WAS] Re: [ANN] parseargs-0.0.0

Hello,

Sorry for the late reply.

On Thu, 02 Jun 2005 21:33:29 +0900, Glenn Parker  
<glenn.parker@comcast.net> wrote:

> Zev Blut wrote:
>>  If you cannot access a in your binding, why would eval add a to the
>> local_variables?  Can anyone explain this?  I would like to know.
>
> It is a curious side effect of the way Ruby is interpreted.  Perhaps it  
> is a performance optimization?  It doesn't really have to be this way,  
> but it won't affect you (much) in practical terms.
>
> Variables that are "visible" when a method is compiled are added to a  
> table somewhere in the AST, and only those variables can be accessed  
> directly in that method.  Clearly, this table is not the same one that  
> "eval" consults so we have, to put it diplomatically, a little  
> disconnect.  Eval can find the variable when asked, but the interpreter  
> simply refuses to go looking for it in the first place.

Thanks a lot for the explanation!  It certainly makes sense now.

Cheers,
Zev