String wrap (by splitting to words)

string_wrap.clj

;; keeps original new-lines, so that there may be shorter lines
;; caveat: if a single word is longer than the split length, it will overflow

(defn split-line [n line]
  (reduce
   (fn [lines word]
     (if (or (empty? lines)
             (>= (+ (count (last lines)) (count word)) n))
       (conj lines word)
       (update lines (dec (count lines)) str " " word)))
   []
   (str/split line #"\s+")))

(defn split-to-length [n text]
  (str/join
   "\n"
   (mapcat (partial split-line n)
           (str/split text #"\n"))))

;; (split-to-length 10 "this is something big\nkeep:\n- items\n- of great length here\nsupercalifragilisticexpialadicous")
;;this is
;;something
;;big
;;keep:
;;- items
;;- of great
;;length
;;here
;;supercalifragilisticexpialadicous