Dysfunctional Programming (phpnw13)

Transcript

1. Dysfunctional Programming
2. @igorwesome
6. Immuteability: The property of functional programmers that prevents them from shutting up about pure functional programming. – Reg Braithwaite @raganwald
7. dys·func·tion·al
8. php λ
9. Paradigms
10. procedural Object- Oriented functional logic
11. Imperative Declarative
12. Structure Time & State
13. Structure
15. ‘sup?
17. it’s not about the money
18. • Message passing • Interfaces • Composition • (Not inheritance)
19. Actor model: Asynchronous
22. f g h
23. tools and materials
24. • Value semantics • Higher-order functions • Lazy evaluation
25. The Garbage Overfloweth
26. $numberCollection = new NumberCollection(); $numberParser = new SimpleNumberStringParser(); $firstParsedNumber = $numberParser->parse('1'); $firstNumber = new SimpleNumber($firstParsedNumber); $firstNumberProxy = new CollectionItemNumberProxy($firstNumber); $numberCollection->add($firstNumberProxy); $secondParsedNumber = $numberParser->parse('1'); $secondNumber = new SimpleNumber($secondParsedNumber); $secondNumberProxy = new CollectionItemNumberProxy($secondNumber); $numberCollection->add($secondNumberProxy); $addition = new AdditionOperator('SimplePHPEasyPlus\Number\SimpleNumber'); $operation = new ArithmeticOperation($addition); $engine = new Engine($operation); $calcul = new Calcul($engine, $numberCollection); $runner = new CalculRunner(); $runner->run($calcul); $result = $calcul->getResult(); $numericResult = $result->getValue();
27. 1 + 1
28. Composition
29. c a b a b
30. a b c
31. Higher-order functions
32. Dependency Injection
33. Inversion of control is really just a pretentious way of saying “Taking an argument”. – Rúnar Óli @runarorama
34. Taking an argument
35. g g’
36. 0 1 2 3 4 even? 0 2 4
37. 0 1 2 3 4 #(+ 5 %) 5 7 9 6 8
38. 3 6 7 9 + 0 9 25 3 16 acumulator
39. Datastructures
40. Number 42 String "Hello, cruel world." Map {:foo "bar", :baz "qux"} List [:a :b :c] Set #{"Arthur Dent" "Ford Prefect"}
41. function is a means of abstraction
42. data is a means of abstraction
43. Structure Time & State
44. Time & State
45. Place-Oriented Programming
50. identity
51. new Foo("x") !== new Foo("x")
52. defensive copy
53. $users = new UserList(); $users->add(new User("Igor")); notify($users);
54. while (count($users)) { $user = $users->shift(); notifyUser($user); }
55. notify(clone $users)
56. observation
57. $user->getName()
58. $user["name"]
59. Value
60. Primitives
61. Value Object
62. date address money response request
63. serialization
64. History
65. Objects are forgetful
66. $sophie->setName("Joanna")
67. 2013-09-13 01:01:47 Sophie 2013-09-13 01:02:25 Joanna 2013-09-13 01:05:31 Caroline
68. $joanna = $sophie->setName("Joanna")
69. Git
70. 98ca9 34ac2 f30ab master Snapshot A Snapshot B Snapshot C
71. Epochal Time Model
72. v1 v2 v3 v4 f f f identity states events
73. Lazy evaluation
74. Iterator Generator Stream
75. a b c d a’ b’ c’ d’ consume
76. Order of execution becomes implicit
77. ๏ filter ๏ map ๏ reduce
78. What about I/O?
79. Filesystem Database Network }is a place
80. Separate I/O from computation
82. What about testing?
83. But I heard static methods are untestable and evil
84. You cannot mock functions
85. Why do we mock?
86. Functions are fast
87. Impure parts are mocked by passing functions
88. my_beautiful_program(function () { return do_evil_shit(); })
89. Pure functions are inherently testable
90. But functions make code look awkward!
91. strlen(get_name(get_user($data)))
92. $data |> get_user |> get_name |> strlen
93. pipeline('get_user', 'get_name', 'strlen')
94. But PHP does not properly support functions!
95. use function igorw\edn\parse; $data = parse($edn);
96. PHP 5.6 will hopefully get function autoloading
97. Applicability of the functional paradigm
98. f g h i j k l
99. A foo foo foo foo B foo foo C foo foo D foo foo E foo foo
100. Granularity
102. Queue
103. ๏ Value semantics ๏ Higher-order functions ๏ Lazy evaluation
104. pure functions
106. Questions? • joind.in/{ 9471, 9472 } • github.com/igorw/edn • github.com/nikic/iter • @igorwesome
107. References • The Paradigms of Programming by Robert W. Floyd • Execution in the Kingdom of Nouns by Steve Yegge • The Value of Values by Rich Hickey • Are we there yet? by Rich Hickey