From: Rob Biedenharn <Rob@...>
Date: 2009-11-24T23:45:28+09:00
Subject: Re: What is __FILE__ and $0? (newbie question)


On Nov 23, 2009, at 9:58 PM, Omar Campos wrote:

> Hi,
>
>  Thanks for your answer. I just wanted to understand a little better
> what it meant.  I don't like to include mystery code in my programs,
> simply because someone says it works and because "you always need to
> include that".  I couldn't find these variables in the Ruby Book
> included with the windows 1.8 distribution, and typing puts __FILE__  
> on
> the interactive ruby console didn't print anything useful (which now
> makes perfect sense!).
>
> Once more, thanks.
> -- 
> Posted via http://www.ruby-forum.com/.
>


That idiom is typically used to include test code within a file that  
is normally used as a library.  The guarded code is run when:
   ruby foo.rb
but not when bar.rb contains
   require 'foo'
as others have pointed out.

Now you should have a "why" to go with your "what" and "how" ;-)

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com