[racket] How can I dump (display) the variables defined in current the global environment

I'm working through the "Little Schemer" and there are literally dozens
of variables defined in the exercises. To run code some significant
subset of these variables needs to be defined - and particular names get
reused frequently with different values.

While this is not a show stopper at the moment and I can and probably
will find a system to organize the definitions, it would be _really_
nice to be able to call a function that would display existing (already
defined) variables in the global environment with their values. And also
a function to save this state (variables in the global environment) in a
fashion that could be quickly/easily (ie one short function call) be
reloaded the next day to continue from where I left off. I have found
one full blown extension on the site that will dump the "environment"
parameters from the opsys but this is not what I'm talking about. I want
the defined variables from the global environment of the current
DrRacket session. And now I think about it, probably _all_ the
definitions for the current session sorted by type.

So. Anybody heard about something like that? I've spent some time
looking for native functions or any extensions that might serve in whole
or in part but so far, nil.

Thanks

Rufus