The Elements of Style in Programming (HWSW Mobile! 2016)

Slide deck from my presentation at HWSW Mobile! 2016 in Budapest.

Transcript

1. The Elements of Style in Programming by Bozhidar Batsov
2. Szervusz!
4. Божидар
5. Bozhidar
6. Bozho cool
7. Bozo not cool
8. Bug cool
10. Magical Sofia City Sofia, Bulgaria
11. Sofia, Bulgaria
13. I’m an Emacs fanatic
14. bbatsov
16. Our beloved leader/CTO
22. Why am I here?
24. size=2 start=0 c=['Н', 'Н' ,'Н' ,'Н' ,'Н','Н','Н','Н','Н','Н','Н','Н','Н','Н'] code_dictionary=Array.new() begin_size_code_dictionary=Array.new() end_string=String.new() code_dictionary=c.uniq.to_a decode_dictionary=c.uniq.to_a for i in 0...code_dictionary.size begin_size_code_dictionary[i]=i end c.size.times{ if !code_dictionary.include?(c[start,size].to_s)#Comparation code_dictionary.push(c[start,size].to_s.chomp) start=start+(code_dictionary.last.size)/2-1 size=2 else size+=1; end } end_code=Array.new(code_dictionary.size) for i in begin_size_code_dictionary.size...code_dictionary.size end_code[i]=code_dictionary.index(code_dictionary[i].chop.chop)+1 end_string+=code_dictionary[i].chop.chop end govnokod. ru
25. Languages are hard
29. Basic usage of a language is easy
30. “Two parts, sometimes lyun, sometimes win, so, first day relyax…”
31. I need an interpreter!
32. “You are the BIGGEST!”
33. The correct usage of a language is hard
34. The effective usage of a language is very hard
35. not really
36. try 10 years
37. http://norvig.com/21- days.html Teach Yourself Programming in Ten Years Peter Norvig
41. Use the active voice.
42. My first visit to Budapest will always be remembered by me. lame
43. I shall always remember my first visit to Budapest. legit
44. The word personally is often unnecessary.
45. Personally, I love Emacs.
46. A style guide • a curated set of (supposedly) good practices • spares you the process of making trivial decisions • allows you to focus on the actual problems • simple and concise
47. Style guides aren’t a replacement for thinking
48. Programs must be written for people to read, and only incidentally for machines to execute. — Hal Abelson
49. Similar rules apply to natural and programming languages
51. English
52. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Chapter I
53. LOREM IPSUM DOLOR SIT AMET, CONSECTETUR ADIPISCING ELIT, SED DO EIUSMOD TEMPOR INCIDIDUNT UT LABORE ET DOLORE MAGNA ALIQUA. UT ENIM AD MINIM VENIAM, QUIS NOSTRUD EXERCITATION ULLAMCO LABORIS NISI UT ALIQUIP EX EA COMMODO CONSEQUAT. DUIS AUTE IRURE DOLOR IN REPREHENDERIT IN VOLUPTATE VELIT ESSE CILLUM DOLORE EU FUGIAT NULLA PARIATUR. EXCEPTEUR SINT OCCAECAT CUPIDATAT NON PROIDENT, SUNT IN CULPA QUI OFFICIA DESERUNT MOLLIT ANIM ID EST LABORUM. LOREM IPSUM DOLOR SIT AMET, CONSECTETUR ADIPISCING ELIT, SED DO EIUSMOD TEMPOR INCIDIDUNT UT LABORE ET DOLORE MAGNA ALIQUA. UT ENIM AD MINIM VENIAM, QUIS NOSTRUD EXERCITATION ULLAMCO LABORIS NISI UT ALIQUIP EX EA COMMODO CONSEQUAT. DUIS AUTE IRURE DOLOR IN REPREHENDERIT IN VOLUPTATE VELIT ESSE CILLUM DOLORE EU FUGIAT NULLA PARIATUR. EXCEPTEUR SINT OCCAECAT CUPIDATAT NON PROIDENT, SUNT IN CULPA QUI OFFICIA DESERUNT MOLLIT ANIM ID EST LABORUM. chapter i
54. Magyar
57. A Fideszt démonizálók közül meglepően sokan képzelik úgy, hogy a kor mánypár t valami nindzsahadsereghez hasonló, tökéletesen kiképzett, arctalan, fegyelmezett katonákból álló sereg, egyfajta f é l e l m e t e s e n h a t é k o n y p o l i t i k a i - é s propagandagépezet. Ugyanezt képzeli ráadásul, nem kis büszkeséggel, egy rakás Fidesz-rajongó is. Egy jó propagandaminiszter viszont tudja, hogy ez az imidzs egy határig kedvező ugyan a pártnak, de ha túlzottan kizárólagossá válik, a választók már nem tudnak azonosulni vele és a túlhajtott profizásnak meg klónhadseregezésnek elhidegülés lesz a vége. Fejezet 1
58. A FIDESZT DéMONIZáLóK KöZüL MEGLEPőEN SOKAN KéPZELIK úGY, HOGY A KORMáNYPáRT VALAMI NINDZSAHADSEREGHEZ HASONLó, T ö K é L E T E S E N K I K é P Z E T T, A R C TA L A N , FEGYELMEZETT KATONáKBóL áLLó SEREG, EGYFAJTA FéLELMETESEN HATéKONY POLITIKAI- éS PROPAGANDAGéPEZET. FeJeZet 1 U G YA N E Z T K é P Z E L I R á A D á S U L , N E M K I S BüSZKESéGGEL, EGY RAKáS FIDESZ-RAJONGó IS. EGY Jó PROPAGANDAMINISZTER VISZONT TUDJA, HOGY EZ AZ IMIDZS EGY HATáRIG KEDVEZő UGYAN A PáRTNAK, DE HA TúLZOTTAN KIZáRóLAGOSSá VáLIK, A VáLASZTóK MáR NEM TUDNAK AZONOSULNI VELE éS A T ú L H A J T O T T P R O F I Z á S N A K M E G KLóNHADSEREGEZéSNEK ELHIDEGüLéS LESZ A VéGE.
59. Ruby
60. def some_method do_something do_more do_more end
61. def some_method do_something do_more do_more end
62. sum=1+2 a,b=1,2 [1,2,3].each{|e|puts e} class FooError<StandardError;end
63. sum = 1 + 2 a, b = 1, 2 [1, 2, 3].each { |e| puts e } class FooError < StandardError; end
64. English
65. Form possessive singular of nouns by adding ’s.
66. Bozhidar’s talk Batman’s batclaw Emacs’s magic
67. Ruby
68. Form predicate method names by adding “?”.
69. even? completed? batman?
70. English
71. Make the paragraph the unit of composition.
72. Ruby
73. Make the method the unit of composition.
74. English
75. Omit needless words.
76. he is a man who
77. Her story is a strange one.
78. Ruby
79. Omit needless words.
80. if some_condition then # body omitted end
81. def some_method # ... return result end
82. English
83. farther further
84. Do we have to go much farther?
85. I decided to pursue the subject further.
86. Ruby
87. == === equal? eql?
88. An approach to style
89. Be consistent
90. English
91. The user should update his config accordingly. They should also check…
92. The user should update his config accordingly. They should also check…
93. Ruby
94. def something coll coll.collect(&:ala) end def something2(coll) coll.map { |x| x.bala } end
95. Be clear
96. Magyar
97. MÁV
98. Megint Állunk Vazze
99. BKV
100. Biztos Késünk Vazze
101. FIDESZ
102. Forintot Ide De SZaporán
103. Ruby
104. $:
105. $LOAD_PATH
106. $;
107. $FIELD_SEPARATOR
108. $*
109. $ARGV
110. '%d %d' % [20, 10]
111. sprintf('%d %d', 20, 10)
112. sprintf( '%{first} %{second}', first: 20, second: 10 )
113. format('%{first} %{second}', first: 20, second: 10)
114. Ruby is optimized for programmer happiness
115. Ruby is a huge language
116. Making the “right” decisions is hard
118. puts "Hello, Budapest!" puts "Hello, Budapest!" puts "Hello, Budapest!"
119. for i in 1..3 puts "Hello, Budapest!" end
120. 3.times do puts "Hello, Budapest!" end
121. 3.times do puts %(Hello, Budapest!) end
122. 3.times do puts %Q(Hello, Budapest!) end
123. 3.times do puts 'Hello, Budapest!' end
124. 3.times do puts %q(Hello, Budapest!) end
127. Are all those options worth our while?
132. 56 simple rules
133. Format a program to help the reader understand it.
134. Write clearly -- don't be too clever.
135. def user_signed_in? !!@current_user end def user_signed_in? !@current_user.nil? end
136. Don't sacrifice clarity for small gains in efficiency.
137. i = 1 res = 0 while i <= 10 res += i i += 1 end
138. (1..10).reduce(:+)
139. (N * (N + 1)) / 2
140. (10 * (10 + 1)) / 2
141. Don't diddle code to make it faster -- find a better algorithm.
142. •Make it right before you make it faster. •Make it fail-safe before you make it faster. •Make it clear before you make it faster.
143. Instrument your programs. Measure before making efficiency changes.
144. Use variable names that mean something.
145. a s l
146. age sex location
147. age_over_18?
148. adult?
149. Don’t repeat yourself.
150. Parenthesize to avoid ambiguity.
151. x || y && z
152. x || (y && z)
153. Keep the code & its comments in sync.
154. # This method does bla bla bla. # It returns an array of results. def bla_bla_bla res = Set.new # ... res end
155. bla_bla_bla[0] # => Boom Boom Pow bla_bla_bla.uniq # => Kaboom!
156. //private instance variable for storing age public static int age;
157. //private instance variable for storing age public static int age;
158. //private instance variable for storing age public static int age;
159. Don’t repeat the code in the comments.
160. # increment counter by 1 counter += 1
161. Don’t comment shitty code — fix it.
162. // // Dear maintainer: // // Once you are done trying to 'optimize' this routine, // and have realized what a terrible mistake that was, // please increment the following counter as a warning // to the next guy: // // total_hours_wasted_here = 42 //
163. Fuck this shit!!!
164. Style guides for programming languages
165. Python
166. PEP-8 http://legacy.python.org/dev/peps/pep-0008/
167. Java
168. Sun Style Guide http://www.oracle.com/technetwork/java/ codeconvtoc-136057.html
169. Google Style Guide https://google-styleguide.googlecode.com/svn/trunk/ javaguide.html
170. Go
171. Effective Go https://golang.org/doc/effective_go.html
172. gofmt
174. Airbnb Style Guide https://github.com/airbnb/javascript
175. Google Style Guide https://google-styleguide.googlecode.com/svn/trunk/ javascriptguide.xml
176. PHP
177. PHP FIG Coding Style Guide http://www.php-fig.org/psr/psr-1/ http://www.php-fig.org/psr/psr-2/
179. Ruby Style Guide https://github.com/bbatsov/ruby-style-guide
180. Clojure
181. Clojure Style Guide https://github.com/bbatsov/clojure-style-guide
182. Swift
183. Swift
184. Swift Style Guide https://github.com/raywenderlich/swift-style-guide
185. Languages are always evolving
186. Good style practices are evolving as well
187. { :batman => 'Bruce', :superman => 'Clark', :zorro => 'Diego', :catwoman => 'Selina' }
188. { batman: 'Bruce', superman: 'Clark', zorro: 'Diego', catwoman: 'Selina' }
189. Style consistency is of paramount importance
190. Community PersonalProject Company
191. Community Project Company
192. Style separates the good from the great!
193. Felina
194. Epilogue twitter: @bbatsov github: @bbatsov http//batsov.com http://emacsredux.com HWSW Mobile! Budapest, Hungary 23.11.2016