From: Dave Burt <dave@...>
Date: 2005-06-04T01:40:28+09:00
Subject: Re: [QUIZ] Whiteout (#34)

> 3.  When "whiteout" is required, the original code must be executed with 
> no
>     change in functionality.

That means that a file that is just "require 'whiteout'" and then a bunch of 
whitespace should run like the original program before it was whited out.

Perl has something called "source filters" (see perl doco "perlfilter"), 
which apply a transformation to following source code, kind of like a 
preprocessor. This would be an ideal way of dealing with this situation, and 
avoid doing File.read($0).

Is there a way to do that in Ruby? Can a C extension concievably alter 
following code before it is parsed? I think I'm expecting a simple "no".

Cheers,
Dave