flengyel-4clojure-solution28.clj

;; flengyel's solution to Flatten a Sequence
;; https://4clojure.com/problem/28
(fn flat [L] (reduce #(if (coll? %2)                   ;; if item is collection
                        (vec (concat %1 (flat %2)))    ;; concat current with flat %2
                        (conj %1 %2))                  ;; otherwise conj at top level
                     [] L))                            ;; empty flattened collection, L