Hi all,
	having to design a usable environment for non
extremely-computer-literate users, I'd like them to fire
up irb with some default options via an alias and write:

Foo> foo = 'life'
Foo> bar = 'the universe'
Foo> baz = 'everything'
Foo> calculate
     ==> 42
Foo>

Here, the calculate() method would (in my dreams) inspect 
the caller's environment, find out the values of foo, bar 
and baz, and use them in its calculation. Of course, in 
the real thing the parameters would be a few more, and
some of them could be omitted. Is there a decent way to 
accomplish this?

Thanks,
	Luigi

P.S. Of course I will accept suggestions for an altogether
     different way of enabling people to use my code. But
     the above seems an interesting problem in its own right,
     and now I got curious :)
P.P.S. RTFM answers are welcome as well, when coupled with
       the relevant reference (I did skim through the pickaxe
       book, but without luck---the reflection thing only 
       seems to apply to the current frame...)