area2.clj

(ns area2
  (:require
    [clojure.math   :as math]
    [criterium.core :as crit]))
(set! *warn-on-reflection* true)
(set! *unchecked-math* false)
(defprotocol IArea
  (area [this]))
(require '[clj-java-decompiler.core :refer [decompile]])
(decompile
 (defrecord Square [^double side]
   IArea
   (area [this]
     (Math/pow side (double 2)))))

(defrecord Rectangle [^double width ^double height]
  IArea
  (area [_]
    (* width height)))

(decompile (defrecord Triangle [^double base ^double height]
             IArea
             (area [_]
               (* 0.5 base height))))
(decompile
 (defrecord Circle [^double radius]
   IArea
   (area [this]
     (* math/PI (Math/pow radius (double 2))))))


(defn make-random-shape []
  (let [shapes  [:square :rectangle :circle :triangle]
        shape   (rand-nth shapes)]
    (case shape
      :square    (->Square (rand-int 10))
      :rectangle (->Rectangle (rand-int 10) (rand-int 10))
      :triangle  (->Triangle (rand-int 10) (rand-int 10))
      :circle    (->Circle (rand-int 10)))))


(defn total-area [shapes]
  (transduce (map area) + shapes))

(defn total-area [shapes]
  (loop [n (double 0)
         xs shapes]
    (if (seq xs)
      (let [s (first xs)]
        (recur (+ n ^double (area s)) (rest xs)))
      n)))

(defn total-area [shapes]
  (reduce (fn [^double tot s]
            (+ tot ^double (area s))) 0 shapes))

(def lots-of-shapes (doall (repeatedly 400000 #(make-random-shape))))