Print diamond kata

core.clj

(ns clojure-dojo.core)

(use '[clojure.string :only (join split)])

(defn letter-index
  [letter]
  (- (int letter) 64))

(defn letter-pairs
  [letter]
  (vec (map-indexed (fn [i a]
    {
      :letter (char a)
      :margin (- (letter-index letter) (inc i))
      :padding (- (* 2 i) 1)
    })
    (range (int \A) (inc (int letter))))))

(defn print-times
  [times string]
  (join (repeat times string)))

(defn print-diamond
  ([letter]
    (loop
      [[pair & pairs] (concat (letter-pairs letter) (reverse (pop (letter-pairs letter))))]

      (when (not (empty? pair))
        (println (str
          (print-times (:margin pair) " ")
          (:letter pair)
          (if (> (:padding pair) 0)
            (str (print-times (:padding pair) " ") (:letter pair))
          )
        ))
        (recur pairs)))))