delay_superfluous_due_to_laziness.clj

(defn words-rows-reducer [row-length [full pending] word]
  (let [total-chars-of-word-and-pending (apply + (count word) (map count pending)) ; this could be fancier, taking into account space width and individual letter width
        adding-word-would-overflow-row (> total-chars-of-word-and-pending row-length)
        store-pending-and-make-new-row (delay [(conj full pending) [word]])
        add-word-to-pending (delay [full (conj pending word)])]
  (if adding-word-would-overflow-row
    @store-pending-and-make-new-row
    @add-word-to-pending)))