The Elements of Style in Ruby (RubyConf.lt)

Slide deck from my talk at RubyConf.lt 2015

Transcript

1. The Elements of Style in Ruby by Bozhidar I. Batsov
2. Sveiki!
9. VP of Engineering
11. (think) http://batsov.com
12. Emacs Redux http://emacsredux.com
13. @bbatsov
14. bbatsov
21. github.com/ bbatsov
22. I’m a perfectionist
23. 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
24. Languages are complex
26. Basic use of a language is relatively easy
28. Ain-tsu-tsvai-tsu-drun
29. “Two parts, sometimes lyun, sometimes win, so, first day relyax"
30. Correct use of a language is hard
31. Effective use of a language is very hard
34. Use the active voice.
35. My first visit to Vilnius will always be remembered by me. lame
36. I shall always remember my first visit to Vilnius. legit
37. The word personally is often unnecessary.
38. Personally, I love Ruby.
39. Style guide • curated set of (supposedly) good practices • frees you from making trivial decisions • allows you to focus on the real problems • short and to the point
40. Convention over configuration
41. Style guides are not substitutes for common sense
42. Common sense is not so common…
43. Programs must be written for people to read, and only incidentally for machines to execute. — Hal Abelson
44. Similar rules apply for natural and programming languages
46. English
47. 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
48. 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
49. Lithuanian
50. Vilniaus miesto apylinkės teismas antradienį paskelbė, kad pripažįsta negaliojančiu Leono Virginijaus Papirčio išrinkimą Lietuvos advokatų tarybos nariu. Su skundu į teismą buvo kreipęsi keturi advokatai – Rūta Čilinskaitė, Jurgita Jurkšaitytė, Gintaris Trakšelis ir Ramūnas Kazlauskas. Jie teigė, kad buvęs Advokatų tarybos pirmininkas L.V.Papirtis neteisėtai vėl kandidatavo į šias pareigas ir neteisėtai buvo išrinktas į Advokatų tarybą, nes įstatai numato dviejų kadencijų ribojimą. Skyrius 1
51. VILNIAUS MIESTO APYLINKėS TEISMAS ANTRADIENį PASKELBė, KAD PRIPAžįSTA NEGALIOJANčIU LEONO VIRGINIJAUS PAPIRčIO IšRINKIMą LIETUVOS ADVOKATų TARYBOS NARIU. sKyIiUS 1 SU SKUNDU į TEISMą BUVO KREIPęSI KETURI ADVOKATAI – RūTA ČILINSKAITė, JURGITA JURKšAITYTė, GINTARIS TRAKšELIS IR RAMūNAS KAZLAUSKAS. JIE TEIGė, KAD BUVęS ADVOKATų TARYBOS PIRMININKAS L.V.PAPIRTIS NETEISėTAI VėL KANDIDATAVO į šIAS PAREIGAS IR NETEISėTAI BUVO IšRINKTAS į ADVOKATų TARYBą, NES įSTATAI NUMATO DVIEJų KADENCIJų RIBOJIMą.
52. Ruby
53. def some_method do_something do_more do_more end
54. def some_method do_something do_more do_more end
55. sum = 1 + 2 a, b = 1, 2 [1, 2, 3].each { |e| puts e } class FooError < StandardError; end
56. sum=1+2 a,b=1,2 [1,2,3].each{|e|puts e} class FooError<StandardError;end
57. English
58. Form possessive singular of nouns by adding ’s.
59. Bozhidar’s talk Batman’s batclaw Emacs’s magic
60. Ruby
61. Form predicate method names by adding “?”.
62. even? completed? batman?
63. English
64. Make the paragraph the unit of composition.
65. Ruby
66. Make the method the unit of composition.
67. English
68. Omit needless words.
69. he is a man who
70. Her story is a strange one.
71. Ruby
72. Omit needless words.
73. if some_condition then # body omitted end
74. def some_method # ... return result end
75. English
76. farther further
77. Do we have to go much farther?
78. I decided to pursue the subject further.
79. Ruby
80. == === equal? eql?
81. 5 === Fixnum Fixnum === 5
82. An Approach To Style
83. Be consistent.
84. Be clear.
85. English
86. CPU
87. COTFLGOHAHA
88. Crawling on the Floor Laughing Guts Out and Having a Heart Attack
89. Lithuanian
90. VU
91. Vilniaus Universitetas
92. ERKP
93. Eesti Riiklik Keskkonnaseire Programm
94. Ruby
95. $:
96. $LOAD_PATH
97. $;
98. $FIELD_SEPARATOR
99. $*
100. $ARGV
101. '%d %d' % [20, 10]
102. sprintf('%d %d', 20, 10)
103. sprintf( '%{first} %{second}', first: 20, second: 10 )
104. format('%{first} %{second}', first: 20, second: 10)
105. Ruby is optimised for programmer happiness.
106. Ruby is a huge language
107. Making the “right” choices is hard
108. puts "Hello, Vilnius!" puts "Hello, Vilnius!" puts "Hello, Vilnius!"
109. for i in 1..3 puts "Hello, Vilnius!" end
110. 3.times do puts "Hello, Vilnius!" end
111. 3.times { puts "Hello, Vilnius!" }
112. 3.times do puts 'Hello, Vilnius!' end
113. Fuck this shit!!!
114. result = [] for name in names result << name.upcase end
115. result = [] names.each do |name| result << name.upcase end
116. names.collect { |name| name.upcase }
117. names.collect(&:upcase)
118. names.map(&:upcase)
119. Fuck this shit!!!
123. 56 simple rules
124. Format a program to help the reader understand it.
125. Write clearly -- don't be too clever.
126. def user_signed_in? !!@current_user end def user_signed_in? !@current_user.nil? end
127. Don't sacrifice clarity for small gains in efficiency.
128. i = 1 res = 0 while i <= 10 res += i i += 1 end
129. (1..10).reduce(:+)
130. (N * (N + 1)) / 2
131. (10 * (10 + 1)) / 2
132. Don't diddle code to make it faster -- find a better algorithm.
133. • 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.
134. Instrument your programs. Measure before making efficiency changes.
135. Use variable names that mean something.
136. a s l
137. age sex location
138. age_over_18?
139. adult?
140. Don’t repeat yourself
141. Parenthesize to avoid ambiguity.
142. x || y && z
143. x || (y && z)
144. Keep the code & its comments in sync
145. # This method does bla bla bla. # It returns an array of results. def bla_bla_bla res = Set.new # ... res end
146. bla_bla_bla[0] # => Boom Boom Pow bla_bla_bla.uniq # => Kaboom!
147. //private instance variable for storing age public static int age;
148. //private instance variable for storing age public static int age;
149. //private instance variable for storing age public static int age;
150. Fuck this shit!!!
151. The Community Ruby Style Guide
152. A short time ago in an office far, far away…
153. Built on solid foundation
155. With the help of a legion of Ruby hackers
156. With a focus on
157. Simplicity
158. Simplicity is the ultimate sophistication.
159. Clarity
160. The Rules • Clear and concise • Illustrated with example code • Linkable • Neatly organised • Community-approved
161. Style rules that only reflect what is easily discoverable by a trivial examination of the source code seem to me to be the least valuable rules. If the style is not conveying additional information, why bother? — Jim Weirich
162. More than 200 rules!
163. Style evolution
164. { :batman => 'Bruce', :superman => 'Clark', :zorro => 'Diego', :catwoman => 'Selina' }
165. { batman: 'Bruce', superman: 'Clark', zorro: 'Diego', catwoman: 'Selina' }
166. object. one. two. three. four
167. object .one .two .three .four
168. private def m1 end def m2 end
169. def m1 end def m2 end private :m1, :m2
170. private def m1 end private def m2 end
172. International • Chinese Simplified • Chinese Traditional • French • Japanese • Portuguese • Russian • Spanish • Vietnamese • Korean
173. Rails Style Guide
174. GitHub Ruby Style Guide
175. Inspiration for other style guides
176. The Elements of Ruby Style ? ?
177. Style consistency
178. Community PersonalProject Company
179. Community Project Company
181. def some_method begin x = 5 h={:a=>1,:b=>2} if not h raise "Some error occurred" end [1, 2, 3].select { |e| e.even? } rescue => e end end
184. Auto-correct
185. def some_method x = 5 h = { a: 1, b: 2 } unless h fail 'Some error occurred' end [1, 2, 3].select(&:even?) rescue => e end
186. Highly customisable
187. You ain’t nothing if you ain’t got style.
188. pabaiga