robert,

Class swapping was brought up on suby-ruby awhile ago under the topic
of "Soul of a New Machine" (among others). The basic idea was an
anology along the following lines:

Lets say you have a Person, that preson does all the usual person
things. But today that person has a job as a Fireman, so he goes to
work and changes modes. Perhaps at night he goes home and must change
modes again and be a Boyfriend (hopefully that means some fun methods
are involved ;-)

Okay so the notion is that an object can take on another level of
abstraction, such that it's instance vars are essentially its "soul"
and they can be embuded into different classes.

It's sort of an inverted way to look the use of #become. But I think, a
much more undersandable and applicable way to look at.

T.