reduce-n

reduce-n.janet

(defn reduce-n
  [f init ind & inds]
  (when (empty? inds)
    (break (reduce f init ind)))
  #
  (var accum init)
  (def n-inds (length inds))
  (loop [[idx el] :pairs ind]
    (set accum 
         (f accum el
            ;(seq [i :range [0 n-inds]]
               (get-in inds [i idx])))))
  #
  accum)

(comment

  # vanilla reduce
  (reduce * 1 [2 3 5 7])
  # =>
  210

  (reduce-n * 1 [2 3 5 7])
  # =>
  210

  (reduce-n + 0 [1 2 3] [4 5 6])
  # =>
  21
 
  (reduce-n * 1 [4 6 8] [6 9 12] [10 15 20])
  # =>
  373248000

  )