C, GCL interface

[Serge D. Mechveliani]

Dear GHC developers,

There is a computer algebra library called DoCon and written in 
Haskell (+GHC).
And I am considering the possibility to extend it with many new methods
by joining some open libraries written in C, C++, and in 
Gnu Common Lisp (GCL).

1. I have seen somewhere the announcement of the C library for numbers, 
   algebraic numbers  by Lenstra and may be, others.
Is it real to design its interface to a Haskell program (DoCon), may be, 
by using some tools from GHC ?  (which tools?)

2. There exists a great volum of math libraries written in Lisp-s,
   in particular, in GCL.
   I believe some of them have a free enough license.
But how to interface to them?
For example, is there possible an interpreter for GCL written in C ?
If it is, then, may be, the GCL libraries can be interfaced by joining
and applying this interpreter at the C data level? 

Also I have looked in the GCL page, and it was not clear where to ask 
about such GCL interpreter.
I never tried these interface tricks and never looked into the Lisp 
design.

Thank you in advance for your advice.

-----------------
Serge Mechveliani
mechvel at botik.ru