domgetter

frames = [
  [10],
  [2,2],
  [10],
  [10],
  [0,2],
  [5,5],
  [5,5],
  [0,0],
  [0,0],

domgetter

;; Timings are after the JVM had done all possible optimizations

(defn asdf [a b] (+ a b))

(dotimes [x 1000] (time (dotimes [x 1000000] (+ 2 3)))) ;; "Elapsed time: 0.280724 msecs"
(dotimes [x 1000] (time (dotimes [x 1000000] (asdf 2 3)))) ;; "Elapsed time: 1.114747 msecs"

(defn asdf ^long [^long a ^long b] (+ a b))

(dotimes [x 1000] (time (dotimes [x 1000000] (+ 2 3)))) ;; "Elapsed time: 0.280724 msecs"

domgetter

Git is Easy

Git is three things
  Objects
  Refs
  commands - CRUD for objects and refs
  
  Shadow Directory (aka index or staging area aka what the next commit will look like)
    untracked files (files which are not in any tree object in HEAD or the shadow directory.  basically, files that git doesnt know about by name)
  

domgetter

a = -> y { -> x { x + y } }
a is pure
a[n] is pure where n is a value
values are pure functions


Typed closures are harder to think about and reason about than dynamic pure functions

Static type checking does not save you from reasoning about concurrency

domgetter

(ns mandelclj.core
  (:gen-class)
  (:import
    (sun.java2d SunGraphics2D)
    (javax.swing JFrame JLabel)
    (java.awt.image BufferedImage)
    (java.awt Dimension Color)
    (java.awt.event ActionEvent
                    ActionListener
                    MouseAdapter

domgetter

;; Winner winner, chicken dinner.  This calcs (mandel (complex. 0 0) 2000) in 15 μs after warmup

(deftype complex [^double real ^double imag])

(defn plus
  "(a + bi) + (c + di) == (a + b) + (c + d)i"
  [^complex z1 ^complex z2]
  (complex. (+ (.real z1) (.real z2)) (+ (.imag z1) (.imag z2))))

(defn magnitude-squared

domgetter

 // Do note that the following java code takes about 8-15 microseconds also

 public class Timing {
    public static void main(String[] Args) {
       for(int i = 0; i < 10000; i++){ // warmup
         thing();
       }
       long start_time = System.nanoTime();
       thing();
       System.out.println(System.nanoTime() - start_time); // tends to print out 8000-15000 which is 8-15 microseconds

domgetter

myapp.core=> (dotimes [x 1500] (time (mandel [0.0 0.0 0.0 0.0] 0 1000)))
"Elapsed time: 0.311213 msecs"
"Elapsed time: 0.230014 msecs" ;; JVM figured out a quick optimization here
"Elapsed time: 0.226392 msecs"
"Elapsed time: 0.232127 msecs"
"Elapsed time: 0.228203 msecs"
"Elapsed time: 0.229411 msecs"
"Elapsed time: 0.23273 msecs"
"Elapsed time: 0.227901 msecs"
"Elapsed time: 0.226996 msecs"

domgetter

(def fruits ["apple" "banana" "orange" "avocado" "pepper" "pumpkin" "grape" "tomato" "blueberry" "raspberry"])
(def users ["John" "Mary" "Joseph"])

; You can be imperative
(for [i (range 0 (count fruits))]
  (.length (fruits i)))
; (5 6 6 7 6 7 5 6 9 9)

; You can be more declarative
(for [fruit fruits]

domgetter

class Integer
  def tags(&block)
    -> {self.times.reduce([]) {|a, i| a << block.yield(i)}}
  end
end

class String
  def to_html
    self
  end