From: Tim Hunter <cyclists@...>
Date: 2004-12-21T01:22:05+09:00
Subject: Convert one object to another

I have two objects, big and little. I need to convert big to little. Big and
little don't have much in common except little's instance variables are a
subset of big's. That is, to convert big to little I need to copy the
instance variables they have in common. What's the right way to do this?
Should I add a "to_little" instance method to big's class, or should I add
a "from_big" singleton method to little's class? Neither one seems right.