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
   

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2. Szervusz!
   

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4. Божидар
   

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5. Bozhidar
   

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6. Bozho
   cool
   

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7. Bozo
   not cool
   

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8. Bug
   cool
   

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10. Magical Sofia City
    Sofia, Bulgaria
    

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11. Sofia, Bulgaria
    

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13. I’m an Emacs
    fanatic
    

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14. bbatsov
    

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16. Our
    beloved
    leader/CTO
    

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22. Why am I here?
    

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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
    

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25. Languages are hard
    

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29. Basic usage of a
    language is easy
    

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30. “Two parts,
    sometimes lyun,
    sometimes win,
    so,
    first day relyax…”
    

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31. I need an interpreter!
    

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32. “You are the BIGGEST!”
    

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33. The correct usage of
    a language is hard
    

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34. The effective usage of a
    language is very hard
    

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35. not really
    

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36. try 10
    years
    

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37. http://norvig.com/21-
    days.html
    Teach Yourself
    Programming in Ten Years
    Peter Norvig
    

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41. Use the active voice.
    

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42. My first visit to
    Budapest will always
    be remembered by me.
    lame
    

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43. I shall always
    remember my first
    visit to Budapest.
    legit
    

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44. The word personally
    is often unnecessary.
    

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45. Personally, I love
    Emacs.
    

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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
    

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47. Style guides aren’t a
    replacement for thinking
    

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48. Programs must be written
    for people to read, and
    only incidentally for
    machines to execute.
    — Hal Abelson
    

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49. Similar rules apply to
    natural and
    programming languages
    

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51. English
    

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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
    

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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
    

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54. Magyar
    

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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
    

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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.
    

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59. Ruby
    

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60. def some_method
    do_something
    do_more
    do_more
    end
    

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61. def some_method
    do_something
    do_more
    do_more
    end
    

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62. sum=1+2
    a,b=1,2
    [1,2,3].each{|e|puts e}
    class FooError

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63. sum = 1 + 2
    a, b = 1, 2
    [1, 2, 3].each { |e| puts e }
    class FooError < StandardError; end
    

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64. English
    

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65. Form possessive
    singular of nouns by
    adding ’s.
    

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66. Bozhidar’s talk
    Batman’s batclaw
    Emacs’s magic
    

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67. Ruby
    

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68. Form predicate
    method names by
    adding “?”.
    

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69. even?
    completed?
    batman?
    

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70. English
    

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71. Make the paragraph
    the unit of
    composition.
    

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72. Ruby
    

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73. Make the method the
    unit of composition.
    

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74. English
    

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75. Omit needless words.
    

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76. he is a man who
    

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77. Her story is a
    strange one.
    

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78. Ruby
    

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79. Omit needless words.
    

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80. if some_condition then
    # body omitted
    end
    

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81. def some_method
    # ...
    return result
    end
    

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82. English
    

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83. farther
    further
    

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84. Do we have to go
    much farther?
    

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85. I decided to pursue
    the subject further.
    

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86. Ruby
    

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87. ==
    ===
    equal?
    eql?
    

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88. An approach to
    style
    

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89. Be consistent
    

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90. English
    

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91. The user should update
    his config accordingly.
    They should also check…
    

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92. The user should update
    his config accordingly.
    They should also check…
    

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93. Ruby
    

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94. def something coll
    coll.collect(&:ala)
    end
    def something2(coll)
    coll.map { |x| x.bala }
    end
    

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95. Be clear
    

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96. Magyar
    

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97. MÁV
    

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98. Megint Állunk Vazze
    

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99. BKV
    

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100. Biztos Késünk Vazze
     

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101. FIDESZ
     

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102. Forintot Ide De
     SZaporán
     

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103. Ruby
     

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104. $:
     

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105. $LOAD_PATH
     

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106. $;
     

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107. $FIELD_SEPARATOR
     

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108. $*
     

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109. $ARGV
     

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110. '%d %d' % [20, 10]
     

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111. sprintf('%d %d', 20, 10)
     

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112. sprintf(
     '%{first} %{second}',
     first: 20, second: 10
     )
     

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113. format('%{first} %{second}',
     first: 20, second: 10)
     

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114. Ruby
     is
     optimized
     for
     programmer
     happiness
     

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115. Ruby is a huge
     language
     

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116. Making the “right”
     decisions is hard
     

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118. puts "Hello, Budapest!"
     puts "Hello, Budapest!"
     puts "Hello, Budapest!"
     

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119. for i in 1..3
     puts "Hello, Budapest!"
     end
     

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120. 3.times do
     puts "Hello, Budapest!"
     end
     

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121. 3.times do
     puts %(Hello, Budapest!)
     end
     

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122. 3.times do
     puts %Q(Hello, Budapest!)
     end
     

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123. 3.times do
     puts 'Hello, Budapest!'
     end
     

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124. 3.times do
     puts %q(Hello, Budapest!)
     end
     

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126. View Slide

127. Are all those options
     worth our while?
     

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131. View Slide

132. 56 simple rules
     

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133. Format a program to
     help the reader
     understand it.
     

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134. Write clearly -- don't
     be too clever.
     

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135. def user_signed_in?
     !!@current_user
     end
     def user_signed_in?
     !@current_user.nil?
     end
     

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136. Don't sacrifice clarity
     for small gains in
     efficiency.
     

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137. i = 1
     res = 0
     while i <= 10
     res += i
     i += 1
     end
     

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138. (1..10).reduce(:+)
     

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139. (N * (N + 1)) / 2
     

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140. (10 * (10 + 1)) / 2
     

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141. Don't diddle code to
     make it faster -- find a
     better algorithm.
     

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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.
     

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143. Instrument your
     programs. Measure before
     making efficiency changes.
     

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144. Use variable names
     that mean something.
     

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145. a
     s
     l
     

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146. age
     sex
     location
     

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147. age_over_18?
     

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148. adult?
     

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149. Don’t repeat
     yourself.
     

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150. Parenthesize to
     avoid ambiguity.
     

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151. x || y && z
     

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152. x || (y && z)
     

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153. Keep the code & its
     comments in sync.
     

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154. # This method does bla bla bla.
     # It returns an array of results.
     def bla_bla_bla
     res = Set.new
     # ...
     res
     end
     

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155. bla_bla_bla[0]
     # => Boom Boom Pow
     bla_bla_bla.uniq
     # => Kaboom!
     

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156. //private instance variable for storing age
     public static int age;
     

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157. //private instance variable for storing age
     public static int age;
     

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158. //private instance variable for storing age
     public static int age;
     

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159. Don’t repeat the code
     in the comments.
     

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160. # increment counter by 1
     counter += 1
     

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161. Don’t comment shitty
     code — fix it.
     

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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
     //
     

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163. Fuck this
     shit!!!
     

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164. Style guides
     for
     programming languages
     

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165. Python
     

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166. PEP-8
     http://legacy.python.org/dev/peps/pep-0008/
     

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167. Java
     

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168. Sun Style Guide
     http://www.oracle.com/technetwork/java/
     codeconvtoc-136057.html
     

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169. Google Style Guide
     https://google-styleguide.googlecode.com/svn/trunk/
     javaguide.html
     

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170. Go
     

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171. Effective Go
     https://golang.org/doc/effective_go.html
     

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172. gofmt
     

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173. View Slide

174. Airbnb Style Guide
     https://github.com/airbnb/javascript
     

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175. Google Style Guide
     https://google-styleguide.googlecode.com/svn/trunk/
     javascriptguide.xml
     

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176. PHP
     

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177. PHP FIG
     Coding Style Guide
     http://www.php-fig.org/psr/psr-1/
     http://www.php-fig.org/psr/psr-2/
     

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178. View Slide

179. Ruby Style Guide
     https://github.com/bbatsov/ruby-style-guide
     

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180. Clojure
     

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181. Clojure Style Guide
     https://github.com/bbatsov/clojure-style-guide
     

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182. Swift
     

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183. Swift
     

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184. Swift Style Guide
     https://github.com/raywenderlich/swift-style-guide
     

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185. Languages are
     always evolving
     

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186. Good style practices
     are evolving as well
     

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187. { :batman => 'Bruce',
     :superman => 'Clark',
     :zorro => 'Diego',
     :catwoman => 'Selina' }
     

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188. { batman: 'Bruce',
     superman: 'Clark',
     zorro: 'Diego',
     catwoman: 'Selina' }
     

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189. Style consistency is of
     paramount importance
     

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190. Community
     PersonalProject
     Company
     

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191. Community
     Project
     Company
     

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192. Style
     separates
     the good
     from
     the great!
     

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193. Felina
     

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194. Epilogue
     twitter: @bbatsov
     github: @bbatsov
     http//batsov.com
     http://emacsredux.com
     HWSW Mobile!
     Budapest,
     Hungary
     23.11.2016
     

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