Best I've been able to come up with is fractions. Though true fractions are rare (and can be converted to a sequence of integers that can be sorted lexicographi

Best I've been able to come up with is fractions. Though true fractions are rare (and can be converted to a sequence of integers that can be sorted lexicographically, see continued fractions). Technically floats qualify, but not in an interesting way since you basically just need to take care of the sign bit and a few special cases. Really most things can be sorted with radix sort, though I wouldn't want to be the one having to implement it for unicode strings (sorting text in general is one of those problems you'd preferably let other people solve for you).