Functional Programming with Clojure

WWCB Clojure session

Transcript

1. ======================================== ! FUNCTIONAL PROGRAMMING WITH CLOJURE ! ========================================
2. 1. SIDE EFFECT FREE 2. IMMUTABILITY 3. FIRST CLASS FUNCTIONS 4. FUNCTION BASED CONTROL FLOW ======================================== FUNCTIONAL PROGRAMMING ======================================== [1] ========================================
3. [2] +-----------------------+ | IMPERATIVE SHELL | | | | +-------------------+ | | | FUNCTIONAL CORE | | | | | | | +-------------------+ | +-----------------------+
4. 1. LISP DIALECT 2. JVM & JS TARGETS 3. DYNAMIC 4. HOMOICONICITY 5. IMMUTABILITY 6. PLATFORM INTEROP 7. SMALL POWERFUL CORE 8. CONCURRENCY ======================================== CLOJURE ======================================== ========================================
5. ======================================== ! SYNTAXING? ! ========================================
6. ======================================== ! ======================================== 1 + 2
7. ======================================== ! ======================================== (+ 1 2)
8. ======================================== ! ======================================== add(1, 2)
9. ======================================== ! ======================================== (add 1, 2)
10. ======================================== ! ======================================== (add 1 2)
11. ======================================== ! ======================================== 1 / 2 * 3
12. ======================================== ! ======================================== (/ 1 (* 2 3))
13. ======================================== ! CLOJURE BY EXAMPLE ! ========================================
14. ➜ brew install leiningen ---------------------------------------- ➜ curl -Lo lein http://bit.ly/1m8fHx2 ➜ chmod a+x lein ➜ ./lein ======================================== INSTALLING LEININGEN ======================================== ========================================
15. ➜ lein repl ! nREPL server started on port ... Clojure 1.6.0 ! user=> ======================================== THE REPL ======================================== ========================================
16. user=> (doc map) ; ------------------ ! user=> (find-doc "fold") ; ------------------ ======================================== THE REPL ======================================== ========================================
17. ======================================== ! DATA TYPES ! ========================================
18. (class 1) (class "Hello") (class 1.0) (class \H) (class true) java.lang.Long java.lang.String java.lang.Double java.lang.Character java.lang.Boolean ======================================== DATA TYPES ======================================== ========================================
19. (class nil) (class (fn [] 1)) (class 5/3) (class :test) (class 'a) nil clojure.lang.IFn clojure.lang.Ratio clojure.lang.Keyword clojure.lang.Symbol ======================================== DATA TYPES ======================================== ========================================
20. (class '(1 2)) (class [1 2]) (class #{1 2}) (class {:a 1 :b 2}) clojure.lang.List* clojure.lang.Vector* clojure.lang.Set* clojure.lang.Map* ======================================== DATA TYPES ======================================== ========================================
21. (= __ true) (= __ (= 2 2/1)) (= :a (keyword __)) (= __ (== 2.0 2)) (= __ (= "a" :a 'a)) (= __ (= 2 2/1)) (not= __ false) (= false (not __)) ======================================== POP QUIZ HOT SHOT ======================================== ======================================== [3]
22. ======================================== ! LISTS, VECTORS & SETS ! ========================================
23. (list 1 2 3 2 1) (vector 1 2 3 2 1) (hash-set 1 2 3 2 1) '(1 2 3 2 1) [1 2 3 2 1] #{1 2 3} ======================================== LISTS, VECTORS & SETS ======================================== ========================================
24. (= __ (count '(42))) (= __ (conj [1 2] 3)) (= __ (cons 1 [2 3])) (= __ (first [1 2 3])) (= __ (last [1 2 3])) ======================================== LISTS, VECTORS & SETS ======================================== ========================================
25. (= __ (rest [1 2 3])) (= __ (nth [1 2 3] 2)) (= __ (peek [1 2 3])) (= __ (pop [1 2 3])) (= __ (rest [])) ======================================== LISTS, VECTORS & SETS ======================================== ========================================
26. ======================================== ! MAPS ! ========================================
27. (hash-map {:a 1}) (hash-map {:a 1 :b}) { :a 1 } ERROR! ======================================== MAPS ======================================== ========================================
28. (= __ (get {:b 2} :b)) (= __ ({:a 1} :a)) (= __ (:a {:a 1})) (= __ (:b {:a 1})) (= __ (:b {:a 1} 2)) ======================================== MAPS ======================================== ========================================
29. (= __ (count {:a 1})) (= __ (:b {:a 1} 2)) (= __ (assoc {:a 1} :b 2)) (= __ (dissoc {:a 1 :b 2} :a)) (= __ (dissoc {:a 1 :b 2} :a :b)) ======================================== MAPS ======================================== ========================================
30. (= __ (contains? {:a nil :b nil} :b)) (= __ (keys {:a 1 :b 2})) (= __ (vals {:a 1 :b 2})) ======================================== MAPS ======================================== ========================================
31. ======================================== ! FUNCTIONS ! ========================================
32. (def sq (fn [a] (* a a))) (defn sq [a] (* a a)) (def sq #(* % %)) ======================================== FUNCTIONS ======================================== ========================================
33. (= __ ((fn [n] (* 5 n)) 2)) (= __ (#(* 15 %) 4)) (= __ (#(+ %1 %2 %3) 4 5 6)) (= __ (#(* 15 %2) 1 2)) (= 9 (((fn [] ___)) 4 5)) ======================================== FUNCTIONS ======================================== ========================================
34. ======================================== ! CONDITIONALS ! ========================================
35. (= __ (if (false? (= 4 5)) :a :b)) (= __ (if (> 4 3) [])) ======================================== CONDITIONALS ======================================== ========================================
36. (let [x 5] (= :your-road (cond (= x __) :road-not-taken (= x __) :another-not-taken :else __))) ======================================== CONDITIONALS ======================================== ========================================
37. (let [choice 5] (= :your-road (case choice __ :road-not-taken __ :your-road :another-not-taken))) ======================================== CONDITIONALS ======================================== ========================================
38. ======================================== ! LOOPING ! ========================================
39. (= __ (loop [v 1] (if-not (> v 5) (recur (inc v)) v)) ======================================== LOOPING ======================================== ========================================
40. ======================================== ! HIGHER ORDER FUNCTIONS ! ========================================
41. (= [__ __ __] (map #(* 4 %) [1 2 3])) (= __ (filter nil? [:a :b nil :c :d])) (= __ (reduce * [1 2 3 4])) ======================================== HIGHER ORDER FUNCTIONS ======================================== ========================================
42. ======================================== ! LAZY SEQUENCES ! ========================================
43. (= __ (range 1 5)) (= __ (range 5)) (= [0 1 2 3 4 5] (take __ (range 100))) (= __ (take 20 (iterate inc 0))) (= [:a :a :a :a :a :a] (repeat __ __)) ======================================== LAZY SEQUENCES ======================================== ========================================
44. ======================================== ! USEFUL MACROS ! ========================================
45. (= __ (-> "a b c d" .toUpperCase (.replace "A" "X") (.split " ") first)) ======================================== USEFUL MACROS ======================================== ========================================
46. (= __ (->> (range) (filter even?) (take 10) (reduce +))) ======================================== USEFUL MACROS ======================================== ========================================
47. (= __ (try (/ 1 0) true (catch Exception e false))) ======================================== USEFUL MACROS ======================================== ========================================
48. ======================================== ! ATOMS ! ========================================
49. (let [my-atom (atom 1)] (= __ @my-atom) (swap! my-atom inc) (= __ @my-atom) (reset! my-atom 4) (= __ @my-atom)) ======================================== ATOMS ======================================== ========================================
50. 1. JAVA INTEROP 2. MACROS 3. DESTRUCTURING 4. RECORDS 5. PROTOCOLS 6. COMPREHENSION 7. TRANSDUCERS 8. CLOJURESCRIPT ======================================== (REST CLOJURE) ======================================== ========================================
51. ======================================== IT’S DANGEROUS TO GO ALONE… ======================================== ======================================== 1. CLOJURE GRIMOIRE 2. WEIRD & WONDERFUL CHARACTERS OF CLOJURE 3. CLOJURE DOCS 4. CLOJURE FOR THE BRAVE AND TRUE
52. ======================================== DEAD TREE EDITION ======================================== ======================================== 1. JOY OF CLOJURE 2ND EDITION 2. PROGRAMMING CLOJURE 3. FUNCTIONAL THINKING 4. STRUCTURE & INTERPRETATION OF COMPUTER PROGRAMS
53. ======================================== ATTRIBUTION ======================================== [1]: http://bit.ly/learning-clojure [2]: http://bit.ly/destroy-all-software [3]: http://bit.ly/clojure-koans [4]: http://bit.ly/clojure-gist ========================================