Turning a string into a variable

["Praveen Kankanala" <mail@...>]

Let's say:

x = "foo"

But now I want to see if foo is an assigned variable (i.e. foo ~= nil 
--- but I obviously don't know what x is equal to so I can't do this) 

So is there someway to find out if a string is also a variable, and if
so to get at the contents of that variable.


Praveen