Implement euclidean division and remainder

[frozolotl]

While the issue #2677 that prompted me to implement these functions has been solved already, Euclidean division and remainder still seem like sensible additions to me.

I'm not sure if I like the documentation, but to me, it appears surprisingly hard to describe these functions in a precise and succinct manner.

[Enivex]

What exactly does this add over quo and rem?

[Dherse]

I think the advantage is that this is integer based? Does it make a difference knowing the cost of eval will be higher than that of the float operation(s)?

[frozolotl]

What exactly does this add over quo and rem?

These are different operations:

• -7 / -3 == 2.(3)
• calc.quo(-7, -3) == 2
• calc.rem(-7, -3) == -1
• calc.div-euclid(-7, -3) == 3
• calc.rem-euclid(-7, -3) == 2

Euclidean division and remainder are used in a few algorithms.
You can see https://en.wikipedia.org/wiki/Euclidean_division for more information on Euclidean division in general.

[Enivex]

What exactly does this add over quo and rem?

These are different operations:

* `-7 / -3 == 2.(3)`

* `calc.quo(-7, -3) == 2`

* `calc.rem(-7, -3) == -1`

* `calc.div-euclid(-7, -3) == 3`

* `calc.rem-euclid(-7, -3) == 2`

Euclidean division and remainder are used in a few algorithms. You can see https://en.wikipedia.org/wiki/Euclidean_division for more information on Euclidean division in general.

I'm fully aware what the euclidean algorithm is, but the only difference here is that rem will return a negative representative for negative numbers. Having both seems redundant, when it's straight-forward to translate between the two.

[frozolotl]

Having both seems redundant, when it's straight-forward to translate between the two.

While that is true, I think the extra bit of convenience for a relatively common mathematical operation is worth it. I consider it similar to functions like min, clamp, or gcd in that sense.

[laurmaedje]

It's always hard to draw the line what's in and out of scope with things like this (and math text operators). Here's the relevant discussion for Rust as a reference: rust-lang/rfcs#2169

[laurmaedje]

Whatever, I don't mind too much either way. Thanks!