Impactos no design com programação funcional

Orientação a Objetos é sem dúvidas o paradigma de programação mais utilizado, mas ultimamente temos visto um crescimento significativo no uso de linguagens funcionais. O objetivo desta palestra é mostrar uma abordagem de design que mostra problemas comuns que temos em orientação a objetos dentro do mundo funcional. Para isso, vamos utilizar um sistema que simula algumas operações de bolsa de valores para mostrar como as decisões tomadas em design OO podem ser mapeadas no mundo funcional através da linguagem Clojure.

Transcript

1. impactos no design com programação funcional Luiz Costa @gutomcosta www.sagadoprogramador.com.br Sunday, October 20, 13
2. Sunday, October 20, 13
3. Programação Funcional? Sunday, October 20, 13
4. Programação Funcional? Sunday, October 20, 13
5. Programação Funcional? Sunday, October 20, 13
6. Programação Funcional? Sunday, October 20, 13
7. Programação Funcional? Sunday, October 20, 13
8. Programação Funcional? e alguns novatos Sunday, October 20, 13
9. orientação a objetos Sunday, October 20, 13
10. Sunday, October 20, 13
11. conjunto de ideias Sunday, October 20, 13
12. conjunto de ideias encapsulamento polimorfismo objetos herança estado ... Sunday, October 20, 13
13. programação funcional Sunday, October 20, 13
14. Sunday, October 20, 13
15. conjunto de ideias Sunday, October 20, 13
16. conjunto de ideias funções higher-order functions imutabilidade lazy evaluation recursão ... Sunday, October 20, 13
17. código imperativo Sunday, October 20, 13
18. código imperativo Sunday, October 20, 13
19. código imperativo Sunday, October 20, 13
20. código imperativo Sunday, October 20, 13
21. código imperativo Foco no “como fazer” Sunday, October 20, 13
22. código declarativo Sunday, October 20, 13
23. código declarativo Foco no “o que fazer” Sunday, October 20, 13
24. código declarativo Sunday, October 20, 13
25. código declarativo Foco no “o que fazer” Sunday, October 20, 13
26. “When writing a modular program to solve a problem, one first divides the problem into subproblems, then solves the subproblems, and finally combines the solutions. The ways in which one can divide up the original problem depend directly on the ways in which one can glue solutions together.” “Why functional programming matters” -John Hughes in Research topics in functional programming, 1990 Sunday, October 20, 13
27. “When writing a modular program to solve a problem, one first divides the problem into subproblems, then solves the subproblems, and finally combines the solutions. The ways in which one can divide up the original problem depend directly on the ways in which one can glue solutions together.” “Why functional programming matters” -John Hughes in Research topics in functional programming, 1990 Sunday, October 20, 13
28. “When writing a modular program to solve a problem, one first divides the problem into subproblems, then solves the subproblems, and finally combines the solutions. The ways in which one can divide up the original problem depend directly on the ways in which one can glue solutions together.” “Why functional programming matters” -John Hughes in Research topics in functional programming, 1990 Sunday, October 20, 13
29. ..argue in the remainder of this paper that functional languages provide two new, very important kinds of glue. “Why functional programming matters” -John Hughes in Research topics in functional programming, 1990 higher order function lazy evaluation Sunday, October 20, 13
30. building blocks Sunday, October 20, 13
31. Sunday, October 20, 13
32. uma variável? Sunday, October 20, 13
33. first class functions uma variável? Sunday, October 20, 13
34. Sunday, October 20, 13
35. invocando uma função função como parâmetro Sunday, October 20, 13
36. invoca a função Sunday, October 20, 13
37. Sunday, October 20, 13
38. dados e funções separados Sunday, October 20, 13
39. mesma função variando comportamento dados e funções separados Sunday, October 20, 13
40. higher order function uma funcão que recebe outra função como argumento ou retorna uma função Sunday, October 20, 13
41. functional style Sunday, October 20, 13
42. OO foco na estrutura Como substituir uma implementação em runtime? Sunday, October 20, 13
43. FP foco na transformação transformação? Sunday, October 20, 13
44. listas, map, reduce, filter Sunday, October 20, 13
45. map Text Text Text Text Sunday, October 20, 13
46. map Text Text Text Text clojure.string Sunday, October 20, 13
47. map jose luiz paulo Text Text Text Text clojure.string Sunday, October 20, 13
48. map capitalize Jose jose luiz paulo Text Text Text Text clojure.string Sunday, October 20, 13
49. map capitalize capitalize Jose Paulo jose luiz paulo Text Text Text Text clojure.string Sunday, October 20, 13
50. map capitalize capitalize capitalize Jose Paulo Luiz jose luiz paulo Text Text Text Text clojure.string Sunday, October 20, 13
51. focus on results, not steps “Functional Thinking” -Neal Ford - IBM Developer Works series Sunday, October 20, 13
52. Filter clojure.string Sunday, October 20, 13
53. Filter clojure.string Sunday, October 20, 13
54. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
55. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
56. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
57. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
58. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
59. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
60. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
61. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
62. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
63. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
64. Filter clojure.string 1 2 3 4 5 6 7 8 9 Sunday, October 20, 13
65. Reduce 10 20 30 40 0 Sunday, October 20, 13
66. Reduce 10 20 30 40 0 função Sunday, October 20, 13
67. Reduce 100 função Sunday, October 20, 13
68. Argentum Análise de Candlesticks, bolsa de valores Sunday, October 20, 13
69. Candlesticks Sunday, October 20, 13
70. Argentum Domain Model Sunday, October 20, 13
71. antes, um pouco de clojure muito pouco mesmo ... Sunday, October 20, 13
72. Clojure Sunday, October 20, 13
73. Clojure Sunday, October 20, 13
74. Clojure Sunday, October 20, 13
75. Clojure Sunday, October 20, 13
76. Clojure Sunday, October 20, 13
77. Clojure Sunday, October 20, 13
78. como representar os conceitos? Negócio, Candlestick Sunday, October 20, 13
79. Sunday, October 20, 13
80. Sunday, October 20, 13
81. Sunday, October 20, 13
82. define uma abstração Sunday, October 20, 13
83. Sunday, October 20, 13
84. dados e funções separados Sunday, October 20, 13
85. dados e funções separados Sunday, October 20, 13
86. decompose an algorithm into functions that are simple, meaningful and useful. “Tutorial on Good Lisp Programming Style” -Peter Norvig in 1992 Sunday, October 20, 13
87. decompose an algorithm into functions that are simple, meaningful and useful. “Tutorial on Good Lisp Programming Style” -Peter Norvig in 1992 Sunday, October 20, 13
88. decomposição Sunday, October 20, 13
89. decomposição Sunday, October 20, 13
90. decomposição invariantes Sunday, October 20, 13
91. decomposição Sunday, October 20, 13
92. decomposição Sunday, October 20, 13
93. decomposição Sunday, October 20, 13
94. decomposição Sunday, October 20, 13
95. decomposição dependência de outro namespace Sunday, October 20, 13
96. Argentum Geração de gráfico com indicadores Sunday, October 20, 13
97. Argentum Geração de gráfico com indicadores define uma abstração Sunday, October 20, 13
98. Argentum Geração de gráfico com indicadores define uma abstração define comportamentos diferentes Sunday, October 20, 13
99. como variar o comportamento? Sunday, October 20, 13
100. declara as funções Sunday, October 20, 13
101. compondo funções Sunday, October 20, 13
102. compondo funções decomposição de função Sunday, October 20, 13
103. compondo funções higher order functions Sunday, October 20, 13
104. calculando a média móvel Sunday, October 20, 13
105. calculando a média móvel Sunday, October 20, 13
106. calculando a média móvel Sunday, October 20, 13
107. calculando a média móvel Sunday, October 20, 13
108. com diferentes building blocks, é preciso repensar as decisões de design Sunday, October 20, 13
109. OO e FP Juntos? Sunday, October 20, 13
110. Functional in the small, OO in the large. “Tell Above, and Ask Below - Hybridizing OO and Functional design” -Michael Feathers, blog post Sunday, October 20, 13
111. Functional Core, imperative shell. “Destroy all software - episode 72” -Gary Bernhardt, destroy on software screen cast series Sunday, October 20, 13
112. conclusão Sunday, October 20, 13
113. Functional Programming is more a mindset than a particular set of tools or languages. “Functional Thinking” -Neal Ford - IBM Developer Works series Sunday, October 20, 13
114. Obrigado Sunday, October 20, 13
115. Referências SICP - http://mitpress.mit.edu/sicp/full-text/book/book.html Why functional programming matters - http://www.cs.kent.ac.uk/people/staff/dat/miranda/whyfp90.pdf Clojure - http://clojure.org/ Functional Thinking - http://www.ibm.com/developerworks/java/library/j-ft1/index.html Tell Above, and ask Below - http://michaelfeathers.typepad.com/michael_feathers_blog/2012/03/ tell-above-and-ask-below-hybridizing-oo-and-functional-design.html Functional Core, imperative shell - https://www.destroyallsoftware.com/screencasts/catalog/ functional-core-imperative-shell Tutorial on good lisp programming style - http://www.cs.umd.edu/~nau/cmsc421/norvig-lisp- style.pdf Sunday, October 20, 13