Slides da apresentação para o IME-Workshop

1. Ruby
Uma introdução
ÍGOR BONADIO

2. Origem

3. Criador
• Yukihiro Matsumoto (Matz)
• Japão, 1995

4. Criador
• Yukihiro Matsumoto (Matz)
• Japão, 1995
“I wanted a scripting language that was
more powerful than Perl, and more
object-oriented than Python3.”
Matz [1]
[1]
h&p://www.linuxdevcenter.com/pub/a/linux/2001/11/29/ruby.html

5. Inspirações: Perl
class Robot
def walk_to(x, y)
@engine.turn_on
@engine.go_to(x, y, $map)
@engine.turn_off
end
end

6. Inspirações: Perl
class Robot
def walk_to(x, y)
@engine.turn_on
@engine.go_to(x, y, $map)
@engine.turn_off
end
end

7. Inspirações: Perl
class Robot
def walk_to(x, y)
@engine.turn_on
@engine.go_to(x, y, $map)
@engine.turn_off
end
end

8. Inspirações: Smalltalk
1.next
# => 2
Robot.methods
# => [:walk_to, ...]

9. Inspirações: Smalltalk
1.next
# => 2
Robot.methods
# => [:walk_to, ...]
"I always knew one day Smalltalk would
replace Java. I just didn't know it would be
called Ruby.”
Kent Beck [2]
[2]
h&p://onsmalltalk.com/objects-­‐classes-­‐and-­‐constructors-­‐smalltalk-­‐style

10. Inspirações: Lisp
[1, 2, 3].map {|n| n*2}
# => [2, 4, 6]
[1, 2, 3].reduce do |acc, n|
acc + n
end
# => 6

11. Ruby
• Script
• Interpretada
• Tipagem forte e dinâmica
– Duck Typing
• Orientada a objetos
• Com características funcionais

12. Ruby + Ecossistema
• RubyGems
• Comunidade ativa
• Diversos tutoriais
– Why (http://mislav.uniqpath.com/poignant-guide/)
• Livros
– Programming Ruby (https://pragprog.com/book/ruby4/
programming-ruby-1-9-2-0)
– Metaprogramming Ruby (https://pragprog.com/book/
ppmetr2/metaprogramming-ruby-2)

13. Configurando e Conhecendo o
Ambiente

14. RVM
• Gerencia diversas versões
– MRI (1.9.3, 2.2.3, etc)
– JRuby
– Rubinious
– MacRuby
– MagLev

15. RVM
$ curl -sSL https://get.rvm.io | bash -s stable

16. RVM
$ curl -sSL https://get.rvm.io | bash -s stable
$ rvm install 2.2.3

17. RVM
$ curl -sSL https://get.rvm.io | bash -s stable
$ rvm install 2.2.3
$ rvm use 2.2.3

18. Note que...
• Ruby funciona muito bem em
– Linux
– OSX
– BSD
• Mas não muito bem em Windows...

19. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 >

20. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 > 1 + 1

21. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 > 1 + 1
=> 2
2.2.0 :002 >

22. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 > 1 + 1
=> 2
2.2.0 :002 > 2.next

23. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 > 1 + 1
=> 2
2.2.0 :002 > 2.next
=> 3
2.2.0 :003 >

24. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 > 1 + 1
=> 2
2.2.0 :002 > 2.next
=> 3
2.2.0 :003 > "blah".u

25. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 > 1 + 1
=> 2
2.2.0 :002 > 2.next
=> 3
2.2.0 :003 > "blah".u
"blah".unicode_normalize "blah".untaint "blah".upcase!
"blah".unicode_normalize! "blah".untrust "blah".upto
"blah".unicode_normalized? "blah".untrusted?
"blah".unpack "blah".upcase
2.2.0 :003 > "blah".u

26. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 > 1 + 1
=> 2
2.2.0 :002 > 2.next
=> 3
2.2.0 :003 > "blah".u
"blah".unicode_normalize "blah".untaint "blah".upcase!
"blah".unicode_normalize! "blah".untrust "blah".upto
"blah".unicode_normalized? "blah".untrusted?
"blah".unpack "blah".upcase
2.2.0 :003 > "blah".upcase

27. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 > 1 + 1
=> 2
2.2.0 :002 > 2.next
=> 3
2.2.0 :003 > "blah".u
"blah".unicode_normalize "blah".untaint "blah".upcase!
"blah".unicode_normalize! "blah".untrust "blah".upto
"blah".unicode_normalized? "blah".untrusted?
"blah".unpack "blah".upcase
2.2.0 :003 > "blah".upcase
=> "BLAH"
2.2.0 :004 >

28. IRB
igorbonadio@marvin:~$ irb
2.2.0 :001 > 1 + 1
=> 2
2.2.0 :002 > 2.next
=> 3
2.2.0 :003 > "blah".u
"blah".unicode_normalize "blah".untaint "blah".upcase!
"blah".unicode_normalize! "blah".untrust "blah".upto
"blah".unicode_normalized? "blah".untrusted?
"blah".unpack "blah".upcase
2.2.0 :003 > "blah".upcase
=> "BLAH"
2.2.0 :004 > exit

29. Interpretador
$ ruby -e "puts 'Hello IME'"
Hello IME

30. Interpretador
$ ruby -e "puts 'Hello IME'"
Hello IME
hello.rb
puts
‘Hello
IME’

31. Interpretador
$ ruby -e "puts 'Hello IME'"
Hello IME
$ ruby hello.rb
Hello IME
hello.rb
puts
‘Hello
IME’

32. Gems
$ gem install jeweler
$ gem list
*** LOCAL GEMS ***
addressable (2.3.7, 2.2.8)
backports (3.6.4)
bigdecimal (1.2.6)
blankslate (2.1.2.4)
builder (3.2.2)
...

33. A Linguagem

34. Declaração de Variáveis
name = "Ígor Bonadio"
NUMBER = 123
$os = "OSX"

35. Tudo é Objeto!
1.next # => 2
"blah".upcase # => "BLAH"
[1, 2, 3].size # => 3

36. Condicionais
if x < 3
comando1
comando2
else
outro_comando1
outro_comando2
outro_comando3
end

37. Laços
while x < 3
comando1
comando2
end
for x in [1, 2, 3]
puts x
end

38. Coleções
["osx", "linux", "windows"].each do |os|
puts "Sistema Operacional compatível: #{os}!"
end
# Sistema Operacional compatível: osx!
# Sistema Operacional compatível: linux!
# Sistema Operacional compatível: windows!

39. Coleções
%w(osx, linux, windows).each do |os|
puts "Sistema Operacional compatível: #{os}!"
end
# Sistema Operacional compatível: osx!
# Sistema Operacional compatível: linux!
# Sistema Operacional compatível: windows!

40. Funções
def sum(a, b)
a + b
end
sum(1, 2) # => 3
sum 4, 5 # => 9

41. Closures
def map(vector, &function)
resp = []
vector.each do |elem|
resp << function.call(elem)
end
resp
end
map([1,2,3]) do |x|
2*x
end
# => [2, 4, 6]

42. Closures
def map(vector, &function)
resp = []
vector.each do |elem|
resp << function.call(elem)
end
resp
end
map [1,2,3] do |x|
2*x
end
# => [2, 4, 6]

43. Strings vs Symbols
color_str = "Orange"
color_sym = :Orange
if color_str == "Blue"
# ...
end
if color_sym == :Blue
# ...
end

44. Classe
class Robot
def initialize(name)
@name = name
end
def walk_to(x, y)
@engine.turn_on
@engine.go_to(x, y, $map)
@engine.turn_off
end
def self.build_evil_robot()
Robot.new("HAL")
end
end

45. Classe
class Robot
def initialize(name)
@name = name
end
def walk_to(x, y)
@engine.turn_on
@engine.go_to(x, y, $map)
@engine.turn_off
end
def self.build_evil_robot()
Robot.new("HAL")
end
end

46. Classe
class Robot
def initialize(name)
@name = name
end
def walk_to(x, y)
@engine.turn_on
@engine.go_to(x, y, $map)
@engine.turn_off
end
def self.build_evil_robot()
Robot.new("HAL")
end
end

47. Classe
class Robot
def initialize(name)
@name = name
end
def walk_to(x, y)
@engine.turn_on
@engine.go_to(x, y, $map)
@engine.turn_off
end
def self.build_evil_robot()
Robot.new("HAL")
end
end

48. Classe
class Robot
def initialize(name)
@name = name
end
def walk_to(x, y)
@engine.turn_on
@engine.go_to(x, y, $map)
@engine.turn_off
end
def self.build_evil_robot()
Robot.new("HAL")
end
end

49. Duck Typing
class Robot
def walk_to(x, y)
#...
end
def bip()
#...
end
end
class Person
def walk_to(x, y)
#...
end
def talk(msg)
#...
end
end
def go_to(obj, x, y)
obj.walk_to(x, y)
end
def bip(obj)
obj.bip()
end
go_to(Robot.new, 1, 2) # ok
go_to(Person.new, 1, 2) # ok
bip(Robot.new) # ok
bip(Person.new) # error

50. Exemplos

51. QuickSort
def sort(array)
return array if array.size <= 1
pivot = array[0]
return sort(array.select { |y| y < pivot }) +
array.select { |y| y == pivot } +
sort(array.select { |y| y > pivot })
end
sort([1, 5, 6, 2, 4, 3])
# => [1, 2, 3, 4, 5, 6]

52. Getters & Setters
class Robot
def name
@name
end
def name=(n)
@name = n
end
def model
@model
end
def model=(m)
@model = m
end
#...
end
robot = Robot.new
robot.name = "HAL"
puts robot.name

53. Getters & Setters
class Robot
attr_accessor :name
attr_accessor :model
attr_accessor :color
attr_accessor :size
#...
end
robot = Robot.new
robot.name = "HAL"
puts robot.name

54. Getters & Setters
class Accessor
def self.create_accessor(accessor_name)
define_method(accessor_name) do
instance_variable_get("@#{accessor_name}")
end
define_method("#{accessor_name}=") do |value|
instance_variable_set("@#{accessor_name}", value)
end
end
end
class Robot < Accessor
create_accessor :name
create_accessor :model
end
robot = Robot.new
robot.name = "HAL"
puts robot.name

55. Getters & Setters
class Object
def self.create_accessor(accessor_name)
define_method(accessor_name) do
instance_variable_get("@#{accessor_name}")
end
define_method("#{accessor_name}=") do |value|
instance_variable_set("@#{accessor_name}", value)
end
end
end
class Robot < Accessor
create_accessor :name
create_accessor :model
end
robot = Robot.new
robot.name = "HAL"
puts robot.name

56. Getters & Setters
class Object
def self.create_accessor(accessor_name)
define_method(accessor_name) do
instance_variable_get("@#{accessor_name}")
end
define_method("#{accessor_name}=") do |value|
instance_variable_set("@#{accessor_name}", value)
end
end
end
class Robot < Accessor
create_accessor :name
create_accessor :model
end
robot = Robot.new
robot.name = "HAL"
puts robot.name

57. Criando Métodos em Tempo de Execução
class Robot
def hello(name)
puts "Hello #{name}"
end
end
robot = Robot.new
robot.hello("IME")
# Hello IME

58. class Robot
def hello(name)
puts "Hello #{name}"
end
end
robot = Robot.new
robot.hello_ime
# => undefined
method
`hello_ime'
for
#<Robot:0x007ff3e9860c38>
(NoMethodError)
Criando Métodos em Tempo de Execução

59. class Robot
def hello(name)
puts "Hello #{name}"
end
def method_missing(method_name)
name = method_name.to_s.gsub("hello_", "")
hello(name.upcase)
end
end
robot = Robot.new
robot.hello_ime
# => Hello IME
robot.hello_igor
# => Hello IGOR
Criando Métodos em Tempo de Execução

60. Active Record
class Group < ActiveRecord::Base
# ...
end
class Posts < ActiveRecord::Base
# ...
end
class User < ActiveRecord::Base
has_many :posts
belongs_to :group
end
user = User.find_by(name: 'Ígor Bonadio')
user.posts # => [...]
user.group.name # => IME

61. RSpec
RSpec.describe User, :type => :model do
it "orders by last name" do
lindeman = User.create!(first_name: "Andy",
last_name: "Lindeman")
chelimsky = User.create!(first_name: "David”,
last_name: "Chelimsky")
expect(User.ordered_by_last_name).to eq([chelimsky,
lindeman])
end
end

62. Links Úteis

63. http://www.rubygems.org

64. https://www.ruby-toolbox.com