I think that this stems from a confusion between the divisibility problem in integer number (on a ring) and the divisibility problem resolved by the perl6 %% operator.
Personally I think that %% is useless while the former is useful and missing. But I have nothing against useless operators On Mon, Dec 11, 2017 at 9:56 PM, Darren Duncan <dar...@darrenduncan.net> wrote: > On 2017-12-11 12:22 PM, Sean McAfee wrote: > >> Well, not really. I don't think x %% 0 should return a Failure at all. >> >> 1 / 0 is an expression which can evaluate to no sensible value, so it >> makes >> sense to fail there. By the question "Is one divisible by zero?" has the >> simple >> answer "No." >> > > I strongly disagree with you. > > First of all, the reason there is no sensible value is that the answer is > BOTH "yes" and "no" at the same time, so you can't choose one. Zero DOES > divide evenly into anything, and typically does so an infinite number of > times. Bottom line, there is no good reason to answer either "yes" or "no" > for zero. > > There are three distinct kinds of answers to the question "is x evenly > divisible by y": > > 1. When dividing x by y there are no leftovers (yes). > 2. When dividing x by y there are leftovers (no). > 3. When dividing anything by zero there is no sensible value (Failure). > > It is very important to distinguish the above 3 cases. > > The main use case of %% is to gate logic where if 2 numbers do evenly > divide we do some particular arithmetic with the results and if they don't > but it is a valid division then we do other particular arithmetic with the > results. > > The expression "x %% y" is to be equivalent to "(x % y) == 0)". > > -- Darren Duncan >
