I'm happy with the API, except that --with-system-libmpdec is naturally broken. So I've to release a new libmpdec, which I'd rather do soon because I don't want to revisit this later. Antoine has looked at the API. If anyone else has requests or objections, now would be a good time to raise concerns. These two functions are the centerpiece of the PR: mpd_uint128_triple_t PyDec_AsUint128Triple(const PyObject *dec) PyObject *PyDec_FromUint128Triple(const mpd_uint128_triple_t *triple)