Our solutions to the puzzles from the Clojure Berlin Meetup in January, in Carp

capitalize-string.carp

; as an introduction, we tried to do string capitalization by hand,
; using as many different interesting idioms as possible

(defn capitalize-char [c]
  (if (Char.lower-case? c)
    (=> c
        (to-int)
        (- 32)
        (from-int))
    c))

(defn capitalize [s]
  (if (= (length s) 0)
    @s
    (let [f (String.head s)]
      (fmt "%c%s" (capitalize-char f) &(String.tail s)))))

game-of-life.carp

(load "git@github.com:hellerve/anima.carp@master")

(use Anima)

(def x 800)
(def y 800)

(defmodule Bool
  (defn random []
    (= 1 (Int.random-between 0 2)))
)

(defn setup [rend] (framerate 3))

(defn state []
  (Array.repeat 80
    &(fn [] (Array.repeat 80 &Bool.random))))

(defn count-neighbors [state i j]
  (Array.reduce
    &(fn [acc coords]
        (+ acc
          (let [x (+ i @(Pair.a coords))
              y (+ j @(Pair.b coords))
              inner (Maybe.from (Array.nth state y) [])]
          (if (Maybe.from (Array.nth &inner x) false)
            1
            0))))
    0
    &[(Pair.init -1 -1)
      (Pair.init -1 0)
      (Pair.init 0 -1)
      (Pair.init -1 1)
      (Pair.init 1 -1)
      (Pair.init 1 1)
      (Pair.init 0 1)
      (Pair.init 1 0)])
)

(defn step [state]
  (do
    (for [i 0 (Array.length &state)]
      (let [row (Array.unsafe-nth &state i)]
        (for [j 0 (Array.length row)]
          (let [cell (Array.unsafe-nth row j)
                neighbors (count-neighbors &state i j)]
            (cond
              (and @cell (and (/= neighbors 2) (/= neighbors 3))) (Array.aset! row j false)
              (and (not @cell) (= neighbors 3)) (Array.aset! row j true)
              ())))))
    state))

(defn draw [rend state]
  (do
    (background rend 200)
    (color rend 20)
    (for [i 0 (Array.length &state)]
      (let [row (Array.unsafe-nth &state i)]
        (for [j 0 (Array.length row)]
          (let [cell (Array.unsafe-nth row j)]
            (when @cell
              (rect rend (* j 10) (* i 10) 10 10))))))
    (step state)))

(defsketch "Game of life" x y setup draw state)