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(ns pascal)

(defn step [row]
  (let [parents (partition 2 1 row)
        new-row-middle (map (fn [[x y]]
                              (+ x y))
                            parents)]
    (concat [1] new-row-middle [1])))

(defonce pascals-triangle

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def ordered_infix(*nums_and_ops)
  initial_val = nums_and_ops[0]
  op_num_pairs = nums_and_ops.drop(1).each_slice(2).to_a
  op_num_pairs.reduce(initial_val) do |accumulator, op_num_pair|
    op, num = op_num_pair
    accumulator.send(op, num)
  end
end

ordered_infix 10, '/', 2, '-', 1, '*', 2

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(defn watch-db []
  (add-watch re-frame.db/app-db :watcher
             (fn [_ _ old-state new-state]
               (let [[removed added] (clojure.data/diff old-state new-state)]
                 (when (or removed added)
                   (println "=====\nRemoved:")
                   (cljs.pprint/pprint removed)
                   (println "Added:")
                   (cljs.pprint/pprint added))))))

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{:result 1}

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{"result": 5}

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# Abstract Class
# ==============
class ISeq
  def first
  end

  def rest
  end

  def [](idx)

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(ns fork-join-recur
  (:import [java.util.concurrent ForkJoinPool
            ForkJoinWorkerThread ForkJoinTask RecursiveTask]))

;; API
;; ===
(def ^:dynamic ^ForkJoinPool *pool* (ForkJoinPool/commonPool))

(defmacro fork [& body]
  `(let [^ForkJoinTask task# (proxy [RecursiveTask] []

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(defn extrapolate
  "Returns a lazy seq produced by extrapolating `coll` with given rules.
  On each iteration,
    `gen-next` is called with the entire seq generated till this iteration
    `shrink` is called with the extrapolated seq (`identity` by default)"
  ([gen-next coll]
   (extrapolate gen-next identity coll))
  ([gen-next shrink coll]
   (concat coll
           (let [curr (volatile! (seq coll))]

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;; clojure solution for https://medium.com/@bellmar/is-cobol-holding-you-hostage-with-math-5498c0eb428b
;; HN: https://news.ycombinator.com/item?id=17636029

(defn rec [y z]
  (- 108
     (/ (- 815
           (/ 1500 z))
        y)))

(defn rec-list [N]

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(ns history)

;; AN EXCERCISE IN TIME TRAVEL
;; ===========================
(defn hatom
  "Atom that remembers previous states."
  [x]
  (atom {:value x
         :history ()}))