would be nice to avoid the overhead of loading Math::GMPf
Thinking a bit more about it, it's no big deal to include an Rmpfr_get_q() XSub in Math::MPFR that does the mpfr_t to mpf_t to mpq_t conversion, and thereby avoids the need to load Math::GMPf.
That function will be in the next release of Math::MPFR.
I'm not sure when that will be - I could send you a patch against current (Math-MPFR-3.28) if you don't want to wait for 3.29.
Cheers, Rob
Comment on Re^3: Converting Math::MPFR to Math::GMPq