Types As Premature Optimization

Presented at Barcelona Ruby Conference 2014

Transcript

1. Types @brixen As Premature Optimization
2. Summary
3. We can't use them well
4. We usually don't need them
5. They can harm more than help
6. Questions?
15. Under-specified What if we put the bread on the floor?
16. Imperative Did we just use temporal coupling?
17. Mutable state How will we know what's in the fridge?
18. Repetitive Never heard of DRY?
19. let a = bread! get a from breadbox! ...! spread b on a!
20. Not abstract How are we going to scale?
21. sandwich(:wheat,! :peanut_butter,! :jelly)
22. sandwich(:rye,! :ham,! :swiss)
23. *LTR Purely functional peanut butter & jelly sandwich (Extra credit: use static typing)
25. General purpose
26. Project failure KPMG (New Zealand) - Dec 2010 70% Had project failure in previous 12 months
27. Project failure McKinsey & Company in conjunction with the University of Oxford - 2012 Failure could threaten company 17%
28. 0 25 50 75 100 Agile Traditional 67 73 Project success Dr Dobbs Journal - Aug 2007, Oct 2011
29. We don't learn from failure
30. We learn from other's failure
31. Programming is a behavioral science Sorry maths people
32. Perception Is it reality?
36. Cognition Is it reality?
37. 3 8
38. 8 3
39. 3 8
40. 3 8
41. 3 8
42. 3 8
43. if even then red
44. if red then even Converse
45. if red then even Converse
46. if ¬even then ¬red Inverse
47. if ¬even then ¬red Inverse
48. if ¬red then ¬even Contrapositive
49. 3 8
50. People who gave incorrect response 90%
51. Propositions as types
54. Statisticians
56. Correct by construction
57. We can't use them well
58. Eight fallacies of programming
59. Same scale 1
62. klocs
63. Same risk 2
65. Same cost 3
66. N * klocs = $
67. Same granularity 4
68. Everything is an object
69. Everything is a function
72. Same abstraction 5
73. Same temporality 6
74. Compile at one point in time
75. Same order 7
78. z → z2 + c
81. They can harm more than help
82. General purpose 8
83. ! nil!
84. nil is not null
85. ! $ nil.to_s! => ""!
86. ! $ nil.to_h! => {}!
87. ! $ nil.to_i! => 0!
88. ! $ nil.to_c! => (0+0i)!
89. id x = x
90. f(g(h(x)))
91. f(g(h(nil))) = nil
92. class NilClass! def method_missing(*)! self! end! end
93. We usually don't need them
94. ! puts "Hello, Barcelona!"!
95. module Kernel! def puts(*args)! # ...! end! ! module_function :puts! end
96. ! puts "Hello, Barcelona!"!
97. fun puts(*args)! # ...! end
98. destroyallsoftware.com
100. fun add(a, b)! a + b! end
101. fun add(a: int, b: int)! a + b! end
102. load_int 0, r1! load_int 1, r2! add r1, r2, r3! # ^a ^b ^c! store_int r3, 2
103. CLIs
104. parsers JSON • YAML • XML/HTML
105. HTTP parsers
106. Garbage collectors
107. General purpose
108. grammar date do! ...! end
109. a = q r!
110. Try Rubinius github.com/rubinius/rubinius
111. # Gemfile! platforms :mri do! gem "ruby-debug"! end!
112. $ bundle update
113. $ bundle exec puma
114. ~2.1
115. 1.8.7
117. Open source is not a spectator sport
119. Don't worry, have fun
120. "Don't worry about people stealing your ideas...
121. "If your ideas are any good, you'll have to ram them down people's throats. —Howard H. Aiken
122. "Sometimes the questions are complicated and the answers are simple" —Dr. Seuss
123. "You never change things by fighting the existing reality...
124. "To change something, build a new model that makes the existing model obsolete." —Buckminster Fuller
125. "No [corporation] can stop an idea whose time has come. —Victor Hugo
126. "Complain about the way other people make software by making software." —Andre Torrez
127. @brixen
128. Thank you!
129. • Chaos: Making a New Science, James Gleick • The Power of Noticing: What the Best Leaders See, Max Bazerman • Smartcuts: How Hackers, Innovators, and Icons Accelerate Success, Shane Snow • You Are Not So Smart, David McRaney • You Are Now Less Dumb, David McRaney • Research Methods: The Basics, Nicholas Walliman • The Art of Thinking Clearly, Rolf Dobelli • Thinking, Fast and Slow, Daniel Kahneman • Intertwingled: Information Changes Everything, Peter Morville • https://en.wikipedia.org/wiki/Cynefin • http://calleam.com/WTPF/?page_id=1445 References
130. • http://commons.wikimedia.org/wiki/File:Peanut-Butter-Jelly-Sandwich.png • https://c1.staticflickr.com/5/4030/4695047698_9fd2da8a9f_z.jpg • http://www.teacher-chef.com/wp-content/uploads/2013/03/3-2013-peanut-butter.jpg • http://upload.wikimedia.org/wikipedia/commons/f/f6/Marmite_thick_spread_toasted_bread.jpg • http://farm3.staticflickr.com/2661/3725885335_61ef015d61_b.jpg • http://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Peanut_butter_and_jelly_sandwich.jpg/ 1024px-Peanut_butter_and_jelly_sandwich.jpg • https://en.wikipedia.org/wiki/Oracle_OpenWorld • http://upload.wikimedia.org/wikipedia/commons/8/86/Ever_Given_container_ship.jpg • http://www.kenrockwell.com/trips/2010-05-nyc/6-01/IMG_7652-po-boxes.jpg • http://clubs1.bg/images/uploads/1237936572timo-glock-driving-with-toyota-hilux-stunt-team-in- melbourne_2.jpg • http://aviewfrommyseat.com/photos/newsmatt-20130923094556.jpg • http://upload.wikimedia.org/wikipedia/commons/1/15/Zombie_costume_portrait.jpg • http://upload.wikimedia.org/wikipedia/commons/d/de/Mandelbrot_set_rainbow_colors.png • http://4.bp.blogspot.com/_GvajRDbRRO4/TLmBW9Kdq5I/AAAAAAAAAp4/q6lyHTE1AuE/s1600/ Mandel_zoom_11_satellite_double_spiral.jpg • http://paulbourke.net/fractals/lorenz/lorenz4.png • http://upload.wikimedia.org/wikipedia/commons/3/39/MashedPotatoes.jpg • http://pixabay.com/static/uploads/photo/2013/03/29/16/27/book-97709_640.jpg Credits