MLton comes within a factor of 1.5 or 2 of C and C++'s runtime speed, at the price of requiring whole-program compilation and having long compilation times. (No

MLton comes within a factor of 1.5 or 2 of C and C++'s runtime speed, at the price of requiring whole-program compilation and having long compilation times. (Not that C++'s compilation times are blazing fast either.) The implementation of a single algorithm is hardly ever big enough a project for long compilation times to become a serious problem, so this seems like an acceptable tradeoff to me.