Expose functions for custom arithmetic fn

[Frozenlock]

I have a safe-divide function returning ##Inf when dividing by zero.

(defn safe-divide [a b]
  (if (zero? b)
    (if (neg? a)
      ##-Inf
      ##Inf)
    (/ a b)))

I'd like to have a version working with broch, but boxed-arithmetic only accepts a few functions from clojure.core.
I understand the logic behind that, but unfortunately writing my own custom boxed-arithmetic turns out to be quite difficult as most of the used functions are private.

Would it be possible to expose those functions?

Alternatively, perhaps boxed-arithmetic could expose two sub-functions where the user could do the dispatch manually?
Something like boxed-mult-div and boxed-add-sub-min-max.

[2food]

Hmm, I think you can get a version of your safe-divide for broch quantities using b/with-num to get the right unit for the given division (with 1/1 so it's a safe division) and then set the number to either ##Inf or ##-Inf.

(defn div-derive [a b]
  (b// (b/with-num a 1) (b/with-num b 1)))

(defn safe-divide-b [a b]
  (if (zero? (b/num b))
    (let [inf (if (neg? (b/num a)) ##-Inf ##Inf)]
      (b/with-num (div-derive a b) inf))
    (b// a b)))

(comment
  (safe-divide-b (b/meters 1) (b/seconds 0))                ; => #broch/quantity[##Inf "m/s"]
  (safe-divide-b (b/meters -1) (b/seconds 0))               ; => #broch/quantity[##-Inf "m/s"]
  )

[2food]

Does this cover your use-case?

[Frozenlock]

With a slight modification to div-derive to handle cases where a and/or b are numbers, it does!

(defn div-derive [a b]
  (b// (if (number? a)
         1
         (b/with-num a 1))
       (if (number? b)
         1
         (b/with-num b 1))))

Thank you very much!