Type inferencing code for CL

Hi,
I'm writing a small utility that allows me to write lispy code that
gets transformed into a pascal like scripting language. It can do some
quite useful things already and saves me a fair bit of typing, but I'd
really like it if I could do things like :-

(pasvar j)
(setv j "hello")
(pasvar k)
(setv k 123)

and I would get...

var j string;
var k integer;
j := 'hello';
k := 123;

....without having to say what type j and k are from the lisp code, ie.
I'd like it if my utility could work out what types j and k are.
Obviously, CL can do this, but I've not easily been able to find where
in SBCL this happens and I would have thought that people would have
done this sort of thing before for translation tools like this.

Does anyone know of a simple way to do type inferencing for a
destination language or perhaps where I could find one as a library?

Thanks & Regards
David