romans.clj

(def table [
    ["M" 1000]
    ["D" 500]
    ["CD" 400]
    ["C" 100]
    ["L" 50]
    ["XL" 40]
    ["X" 10]
    ["IX" 9]
    ["V" 5]
    ["IV" 4]
    ["I" 1]])

(defn roman [i table]
  (cond
    (= i 0) ""
    (= table '()) ""
    :else
      (let [
        symbl (first (first table))
        value (last (first table))
        quotient (unchecked-divide-int i value)
        roman-head-str (apply str (repeat quotient symbl))
        roman-tail-str (roman (- i (* quotient value)) (rest table))]
        (apply str roman-head-str roman-tail-str))))

(defn test-roman [i]
  (printf "roman(%s): %s\n" i (roman i table)))

(run! test-roman [1 3 4 5 6 8 9 10 11 14 15 16 39 40 49 50 99 100])