;; Mesure performances.

(load-file      "../lib/load-file-once.mal")
(load-file-once "../lib/trivial.mal")   ; gensym inc

;; Evaluate an expression, but report the time spent
(defmacro! time
  (fn* (exp)
    (let* [start (gensym)
           ret   (gensym)]
      `(let* (~start (time-ms)
              ~ret   ~exp)
        (do
          (println "Elapsed time:" (- (time-ms) ~start) "msecs")
          ~ret)))))

;; Count evaluations of a function during a given time frame.
(def! run-fn-for

  (let* [
    run-fn-for* (fn* [fn max-ms acc-ms last-iters]
      (let* [start (time-ms)
             _ (fn)
             elapsed (- (time-ms) start)
             iters (inc last-iters)
             new-acc-ms (+ acc-ms elapsed)]
        ;; (do (prn "new-acc-ms:" new-acc-ms "iters:" iters))
        (if (>= new-acc-ms max-ms)
          last-iters
          (run-fn-for* fn max-ms new-acc-ms iters))))
    ]

    (fn* [fn max-secs]
      ;; fn       : function without parameters
      ;; max-secs : number (seconds)
      ;; return   : number (iterations)
      (do
        ;; Warm it up first
        (run-fn-for* fn 1000 0 0)
        ;; Now do the test
        (run-fn-for* fn (* 1000 max-secs) 0 0)))))