GHC Task Ticket # 601 suggests replacing GMP with OpenSSL's Bignum library, BN. I have two questions concerning this: (1) Why not use the ARbitrary PRECision Computation Package (ARPREC) by David Bailey, Yozo Hida, Karthik Jeyabalan, Xiaoye Li and Brandon Thompson? Here is a reference web page: http://crd.lbl.gov/~dhbailey/mpdist/ ARPREC is written in C++ but supports calls from C (see include/arprec/c_mp.h in the distribution directory). ARPREC is very fast and supports more complex mathematics than BN. The Licensing for ARPREC is not a problem: essentially similar to BSD3. Note that there would be a basic configuration fix for building OpenSSL's BN library on OS 10.4: you would probably--I had to, myself--have to temporarily move the default installation of /usr/lib/libssl0.9.dylib (and variants) if you want to create a shared (.a) library because Apple's ln links dynamic libraries in preference to shared libraries. Those of you who have some experience with Apple's gcc also know that Apple's gcc does not recognise the -shared flag. (2) A much more aesthetic solution would be to replace any external Bignum library with a pure Haskell library. There are many problems with building a truly efficient and fast Bignum library in Haskell but challenges like that are how languages evolve... -Peter Tanski