Techtalk - My method is missing!

Esta apresentação foi ministrada em um curso de desenvolvimento e a traz uma dinâmica acerca da implementação do algoritmo de method lookup e constant lookup do ruby.

Transcript

1. My METHOD is MISSING! ?? ? ?
2. { “name”: “Gabriel Ferreira”, “github”: “@gleopoldo” }
7. Por que falar de method dispatch?
8. 1. Ruby é uma linguagem orientada a objetos
9. Alan Kay and OO Programming “Objects communicate by sending and receiving messages” Alan Kay
10. 2. Técnicas de debugging
12. 3. Metaprogramming
15. 4. Curiosidade
18. “Tudo em Ruby é um objeto” X
19. “Tudo em Ruby é um objeto” X
20. Object#is_a? Object#object_id
21. Understanding the ruby object model
22. “Em Ruby, classes surgiram antes dos objetos” X
23. “Em Ruby, classes surgiram antes dos objetos” X
24. class.h
25. ruby.h
26. ruby.h
27. messages and interfaces
28. Message Oriented Design Object A communication between objects Object C Object B communication between objects
29. Message Oriented Design - Example class Charger # … def reload(chargeable) chargeable.energy = 100 end end class Robot def reload_battery() Charger.new.reload(self) end def energy=(amount) @energy += amount end end
30. A troca de mensagens é muito mais impactante na definição de uma arquitetura que os objetos participantes
32. Sandi Metz
33. How to deal with interfaces: The PUBLIC interface My Object Interface other objects may interact through this API usually defined as: class MyObject # … # … end The PRIVATE interface no external access STABLE API shouldn’t change frequently UNSTABLE API may change frequently
34. class Robot def do_things() # ... end private def check_battery() # ... end end How to deal with interfaces: My Object Interface other objects may interact through this API no external access STABLE API shouldn’t change frequently UNSTABLE API may change frequently
35. “Métodos privados em ruby são inacessíveis” X
36. “Métodos privados em ruby são inacessíveis” X
37. Object#send Object#public_send
39. “Usar ‘private’ torna toda definição de método após ele privado” X
40. “Usar ‘private’ torna toda definição de método após ele privado” X
41. self and lexical scope
42. class Robot def do_things() # ... end def check_battery() # ... end def self.create() # ... end end Lexical Scopes Robot object scope class Robot scope
43. class Robot def self.do_things() # ... end def self.check_battery() # ... end private def self.create() # ... end end Lexical Scopes Robot object scope class Robot scope
44. class Robot class << self def do_things() # ... end private def self.create() # ... end end end Lexical Scopes Robot object scope class Robot scope
45. Você não precisa necessariamente instanciar um objeto para chamar um comportamento, classes também são objetos
46. “Métodos de classe são armazenados nas classes” X
47. “Métodos de classe são armazenados nas classes” X
48. Object#singleton_class ObjectSpace#count_objects
49. method dispatch
51. Object#ancestors
52. Method dispatch algorithm ... ruby object parent class grandpa class Object class BasicObject class respond to #method ??? maybe you respond to #method ? and what about you? long and patient lookup…. please… help... OK! my life is a lie, BYE!
53. “É impossível fazer herança múltipla em Ruby” X
54. “É impossível fazer herança múltipla em Ruby” X
55. Module#include Module#prepend Module#extend
56. “É possível interceptar qualquer chamada de método para qualquer objeto” X
57. “É possível interceptar qualquer chamada de método para qualquer objeto” X
59. Object#method_missing
60. Method dispatch algorithm (Part 1) ... ruby object parent class grandpa class Object class BasicObject class respond to #method ??? maybe you respond to #method ? and what about you? long and patient lookup…. please… help...
61. ... ruby object parent class grandpa class Object class BasicObject class respond to #method ??? maybe you respond to #method ? and what about you? long and patient lookup…. please… help... OOPS! Let’s try again! Method dispatch algorithm (Part 1)
62. ... ruby object parent class grandpa class Object class BasicObject class call method_missing! now you... and falls into the loop again. OK! Your last chance! Method dispatch algorithm (Part 2)
63. ... ruby object parent class grandpa class Object class BasicObject class OK! my life is a lie, BYE! Method dispatch algorithm (Part 2)
64. ... ruby object parent class grandpa class Object class BasicObject class OK! my life is a lie, BYE! respond to #method ??? maybe you respond to #method ? and what about you? long and patient lookup…. please… help... OOPS! Let’s try again! call method_missing! now you... and falls into the loop again. OK! Your last chance! Method dispatch algorithm (Full view)
66. Alan Kay and OO Programming Basics of Ruby method dispatch system
67. Sandi Metz
68. Pat Shaughnessy
69. Dúvidas? Gabriel Ferreira Github: @gleopoldo gabrielleopferreira@gmail.com https://www.linkedin.com/in/gabriel-leopoldo/