But then you can't have generic functions that are efficient at run-time and work at compile-time ? This feature is added to c++ not for fun but because if you

But then you can't have generic functions that are efficient at run-time and work at compile-time ? This feature is added to c++ not for fun but because if you can't have a run-time branch that will do some AVX-fu, or invoke some runtime function from BLAS or LAPACK, the whole "evaluate at compile-time" thing is... Not useless but not far either