Ruby for Java minds

Transcript

1. RUBY FOR JAVA MINDS

2. $ whoami

3. @janogonzalez

4. @hop_in

5. HISTORY

6. THE 90’S

7. BIG CHANGES

8. None

9. COLD WAR IS OVER

10. None

11. GRUNGE GOES MAINSTREAM

12. APATHY

13. SELF- ALIENATION

14. ANGST IS THE NEW COOL

15. MEANWHILE IN THE PROGRAMMING WORLD...

16. RAISING AGAINST THE MAINSTREAM

17. JAMES GOSLING

18. JAMES GOSLING

19. JAVA

20. “Write Once, Run Anywhere”

21. THE 5 PRINCIPLES • It should be "simple, object-oriented and

    familiar" • It should be "robust and secure" • It should be "architecture-neutral and portable" • It should execute with "high performance" • It should be "interpreted, threaded, and dynamic"

22. (THAT WAS NOT RSPEC)

23. MATZ

24. MATZ

25. RUBY

26. “Ruby is designed to make programmers happy”

27. MATZ WINS THE NOBEL PEACE PRICE

28. (HISTORICAL ACCURACY IS OVERRATED)

29. 2 DIFFERENT PHILOSOPHIES

30. HOW DO WE EMBRACE RUBY?

31. MY HISTORY

32. Y2K

33. COMPUTER APOCALYPSE DID NOT HAPPEN

34. I WENT TO A “JAVA SCHOOL”

35. JAVA EE, SPRING AND CUBICLES

36. HEY, RAILS LOOK COOL!

37. HEY, THERE IS A FLY OVER THERE!

38. (STUPID FLY)

39. THE 10’S

40. RAILS VS JAVA EE WAS OVER

41. HEY, RUBY LOOKS COOL!

42. WAIT, HOW DO I DECLARE AN INTERFACE?

43. None

44. THE PROBLEM

45. “The determined Real Programmer can write FORTRAN programs in any

    language.” –Ed Post

46. HOW TO WRITE RUBY THAT FEELS LIKE RUBY?

47. A ZEN MOMENT

48. ॳ৺

49. BEGINNER’S MIND

50. EMPTY YOUR CUP

51. BACK TO BASICS

52. THE KEY TO UNDERSTAND RUBY

53. EXPRESSIONS + OBJECTS

54. SYNTAX IS EXPRESSION-ORIENTED

55. “LISP programmers know the value of everything and the cost

    of nothing.” - Alan Perlis

56. EXPRESSIONS def average(a, b) (a + b) / 2 end

    # => nil average(10, 2) # => 6

57. EXPRESSIONS level = case when 1..2 then :excellent when 3..5

    then :normal else :bad end

58. ALL VALUES ARE OBJECTS

59. OBJECTS -1.class # => Fixnum

60. OBJECTS String.object_id # => 70138854779960

61. OBJECTS nil.nil? # => true

62. WO IST DEIN GOTT JETZT

63. MESSAGES

64. MESSAGES EVERYWHERE

65. MESSAGES 40 + 2 # => 42

66. MESSAGES 40.+(2) # => 42

67. MESSAGES 40.send(:+, 2) # => 42

68. MESSAGES ≠ METHODS

69. MESSAGES class AccountProtectionProxy def initialize(real_account, owner) @subject = real_account @owner

    = owner end ...

70. MESSAGES class AccountProtectionProxy ... def method_missing(name, *args) check_access @subject.send(name, *args)

    end ... end

71. DYNAMIC TYPING

72. FORGET ABOUT JAVA INTERFACES

73. JAVA public interface Report { ReportFile generate(); }

74. JAVA public class PDFReport implements Report { .... }

75. JAVA public class CSVReport implements Report { .... }

76. JAVA public void print(List<Report> reports) { if (reports == null)

    { return; } for (Report r : reports) { ReportFile file = r.generate(); ... } }

77. DYNAMIC TYPING def print(reports) [*reports].each do |r| file = r.generate

    ... end end

78. DYNAMIC TYPING class PDFReport def generate ... end ... end

79. DYNAMIC TYPING class CVSReport def generate ... end ... end

80. DYNAMIC TYPING class Duck def generate ... end ... end

81. PROGRAM TO INTERFACES, NOT TO interface

82. USED EVERYWHERE

83. DYNAMIC TYPING "Jano in " << "Berlin" # => "Jano

    in Berlin" ["Santiago"] << "Berlin" # => ["Santiago", "Berlin"]

84. IF YOU REALLY NEED TO CHECK...

85. DYNAMIC TYPING if report.respond_to?(:generate) report.generate ... else ... end

86. IF YOU REALLY, REALLY NEED TO CHECK...

87. DYNAMIC TYPING if report.is_a?(Report) report.generate ... else ... end

88. DYNAMIC BUT NOT WEAK

89. STRONG TYPING 100 + 'cool' # TypeError: String can't be

    coerced into Fixnum

90. TYPE CONVERSIONS

91. CONVERSIONS 100 + 'cool'.to_i # => 100 100 + Integer('cool')

    # ArgumentError: invalid value for Integer(): "lala"

92. BLOCKS

93. BLOCKS ARE USED & ABUSED IN RUBY

94. PROGRAM LIKE A BOSS

95. (LITERALLY)

96. BLOCKS (1..100).select { |n| n % 3 == 0 }

    .map { |n| n * 2 } .reduce(:+)

97. FLUID CODE

98. BLOCKS File.open('my.txt').each do |line| puts line if line =~ /jano/

    end

99. BE MORE DECLARATIVE

100. BLOCKS words.sort do |a, b| a.length <=> b.length end words.min_by?

     { |w| w.length } words.reject { |w| w.length > 8 } # etc...

101. EXAMPLE: SELF YIELD

102. BLOCKS class Job def initialize yield self if block_given? end

     ... end

103. BLOCKS job = Job.new do |j| j.name = 'Print Reports'

     j.user = 'janogonzalez' ... end

104. EXAMPLE: CALLBACKS

105. BLOCKS class Job def on_finish(&block) @end_callback = block end def

     execute() ... @end_callback.call(self) if @end_callback end end

106. BLOCKS job.on_finish do |j| puts "Finished job #{j.name}" puts "Status:

     #{j.status}” end

107. MIXINS

108. MODULES AS MIXINS

109. ADD BEHAVIOR TO INSTANCES

110. MODULES module Model def persist ... end end

111. MODULES class User include Model ... end

112. MODULES job = User.new('Jano') job.persist

113. ADD BEHAVIOR TO CLASSES

114. MODULES module Findable def find_by_id(id) ... end end

115. MODULES class User extends Findable ... end

116. MODULES user = User.find_by_id(3)

117. METAPROGRAMMING

118. (USE WITH CAUTION)

119. (AKA THE EVAL IS EVIL RULE)

120. ACCESSORS

121. ACCESSORS class User attr_reader :name attr_reader :status end

122. OPEN CLASSES

123. OPEN CLASSES class Range def even select(&:even?) end end (0..10).even

     # => [2, 4, 6, 8, 10]

124. OPEN CLASSES class BuggyClass def buggy_method # the fix ...

     end end

125. OPEN CLASSES class Job alias_method :old_execute, :execute def execute ...

     old_execute end end

126. DEFINE METHODS

127. DEFINE METHODS obj = User.new User.class_eval do def represent ...

     end end obj.represent

128. DEFINE METHODS User.instance_eval do def random ... end end User.random

129. SINGLETON METHODS

130. SINGLETON METHOD obj = Person.new class << obj def represent

     ... end end obj.represent

131. (A LOT MORE TO EXPLORE...)

132. ONE LAST ADVICE

133. कഁ཭

134. SHU कഁ཭

135. HA कഁ཭

136. RI कഁ཭

137. None

138. CONCLUSIONS

139. EMBRACE DYNAMIC TYPING

140. BE MORE DECLARATIVE

141. WRITE LESS DO MORE

142. CONVENTIONS AND IDIOMS ARE NOT LAWS

143. THERE IS NO TRUE PATH

144. ENJOY RUBY! (AND JAVA TOO)

145. DANKESCHÖN!

146. ¡MUCHAS GRACIAS!

147. IMAGES • http://006.shanbara.jp/movie/data/fat1367385194099.jpg • http://wfiles.brothersoft.com/n/nirvana-desktop_157301-1600x1200.jpg • http://stilestili.com/wp-content/uploads/2013/04/Ryan- Gosling2-2048x2560.jpg • http://upload.wikimedia.org/wikipedia/commons/thumb/1/14/

     James_Gosling_2008.jpg/1018px-James_Gosling_2008.jpg • http://www.flickr.com/photos/john_lam/1910968816/