The Elements of Style in Programming (WebCamp Zagreb 2015)

Slide deck from my talk at WebCamp Zagreb 2015.

Transcript

1. The Elements
   of
   Style
   in
   Programming
   by Bozhidar Batsov
   

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2. Dobar dan Zagrebe!
   

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3. Божидар
   

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4. Božidar
   

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5. View Slide

6. View Slide

7. I’m an Emacs
   fanatic
   

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8. bbatsov
   

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9. View Slide

10. Sasha,
    our
    beloved
    leader/CTO
    

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11. View Slide

12. @bbatsov
    

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13. View Slide

14. Why am I here?
    

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15. View Slide

16. 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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17. Languages are hard
    

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18. View Slide

19. Basic usage of a
    language is easy
    

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20. Pipl mast trast as
    

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21. "I was day after 

    yesterday

    in Hungary"
    

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22. The correct usage of
    a language is hard
    

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23. The effective usage of
    a language is very hard
    

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24. not really
    

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25. try 10 years
    

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

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27. View Slide

28. View Slide

29. View Slide

30. Use the active voice.
    

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31. My first visit to Zagreb will
    always be remembered by me.
    lame
    

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32. I shall always remember my
    first visit to Zagreb.
    legit
    

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33. The word personally
    is often unnecessary.
    

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34. Personally, I love Emacs.
    

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35. 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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36. Style guides aren’t a
    replacement for thinking
    

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

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38. Similar rules apply to
    natural and programming
    languages
    

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39. View Slide

40. English
    

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41. 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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42. 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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43. Hrvatski
    

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44. Trebaju nam promjene prema otkrivanju i održavanju perspektive razvoja i
    napretka. Naša koalicija najavljuje promjene – promjene koje će oživjeti
    gospodarstvo kao podlogu razvitka, koje će teret reformi ravnomjernije
    podijeliti između bogatih i siromašnih, koje će omogućiti odgovornu,
    funkcionalnu i poštenu upravu, koje će racionalizirati potrošnju i javni rashod,
    a osigurati standard građana, koje će uvesti pravo zajednice na dio dobiti
    koju pojedinci izvlače ekstraprofitom, pretvarajući tuđi rad u svoju imovinu.
    

    Mi najavljujemo promjenu prirode hrvatskoga kapitalizma i konačni odmak
    od prakse kapitalizma perifernoga, nekontroliranog, pa i nezakonitog profita,
    bogaćenja na štetu nacionalnih interesa i podcjenjivanja i odbacivanja prava
    rada i radnika. Naše promjene ne vode prema slabljenju države, nego prema
    jačanju uloge odgovorne države, a istodobno jačanju uloge njezinih građana.
    Poglavlje 1
    

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45. TREBAJU NAM PROMJENE PREMA OTKRIVANJU I ODRŽAVANJU
    PERSPEKTIVE RAZVOJA I NAPRETKA. NAŠA KOALICIJA NAJAVLJUJE
    PROMJENE – PROMJENE KOJE ĆE OŽIVJETI GOSPODARSTVO KAO
    PODLOGU RAZVITKA, KOJE ĆE TERET REFORMI RAVNOMJERNIJE
    PODIJELITI IZMEĐU BOGATIH I SIROMAŠNIH, KOJE ĆE OMOGUĆITI
    ODGOVORNU, FUNKCIONALNU I POŠTENU UPRAVU, KOJE ĆE
    RACIONALIZIRATI POTROŠNJU I JAVNI RASHOD, A OSIGURATI STANDARD
    GRAĐANA, KOJE ĆE UVESTI PRAVO ZAJEDNICE NA DIO DOBITI KOJU
    POJEDINCI IZVLAČE EKSTRAPROFITOM, PRETVARAJUĆI TUĐI RAD U
    SVOJU IMOVINU.
    pOgLaVljE 1
    MI NAJAVLJUJEMO PROMJENU PRIRODE HRVATSKOGA
    KAPITALIZMA I KONAČNI ODMAK OD PRAKSE KAPITALIZMA
    PERIFERNOGA, NEKONTROLIRANOG, PA I NEZAKONITOG PROFITA,
    B O G A Ć E N J A N A Š T E T U N A C I O N A L N I H I N T E R E S A I
    PODCJENJIVANJA I ODBACIVANJA PRAVA RADA I RADNIKA.
    SADAŠNJA VLAST SAMO JE ZAŠTITNIK I JAMAC NASTAVKA TAKVE
    PRAKSE. NAŠE PROMJENE NE VODE PREMA SLABLJENJU DRŽAVE,
    NEGO PREMA JAČANJU ULOGE ODGOVORNE DRŽAVE
    

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46. Ruby
    

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47. def some_method
    do_something
    do_more
    do_more
    end
    

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48. def some_method
    do_something
    do_more
    do_more
    end
    

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

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

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51. English
    

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

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

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54. Ruby
    

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

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56. even?
    completed?
    batman?
    

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57. English
    

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58. Make the paragraph
    the unit of composition.
    

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59. Ruby
    

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60. Make the method the
    unit of composition.
    

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61. English
    

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62. Omit needless words.
    

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63. he is a man who
    

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64. Her story is a strange
    one.
    

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65. Ruby
    

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66. Omit needless words.
    

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67. if some_condition then
    # body omitted
    end
    

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68. def some_method
    # ...
    return result
    end
    

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69. English
    

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70. farther
    further
    

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71. Do we have to go
    much farther?
    

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72. I decided to pursue
    the subject further.
    

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73. Ruby
    

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74. ==
    ===
    equal?
    eql?
    

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75. An approach to
    style
    

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76. Be consistent
    

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77. English
    

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

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

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80. Ruby
    

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

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82. Be clear
    

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83. Hrvatski
    

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84. HP
    

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85. Hladno Pivo
    

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86. DNK
    

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87. Da
    Nije
    Komšijin
    

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88. USKOK
    

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89. Ured za suzbijanje korupcije
    i organiziranog kriminaliteta
    

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90. Ruby
    

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91. $:
    

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92. $LOAD_PATH
    

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93. $;
    

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94. $FIELD_SEPARATOR
    

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95. $*
    

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96. $ARGV
    

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

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

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

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

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101. Ruby
     is
     optimized
     for
     programmer
     happiness
     

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102. Ruby is a huge
     language
     

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103. Making the “right”
     decisions is hard
     

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104. puts "Hello, WebCamp!"
     puts "Hello, WebCamp!"
     puts "Hello, WebCamp!"
     

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105. for i in 1..3
     puts "Hello, WebCamp!"
     end
     

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106. 3.times do
     puts "Hello, WebCamp!"
     end
     

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107. result = []
     names.each do |word|
     result << name.upcase
     end
     

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108. names.map { |name| name.upcase }
     

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109. names.map(&:upcase)
     

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110. View Slide

111. View Slide

112. View Slide

113. 56 simple rules
     

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

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

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

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

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

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119. (1..10).reduce(:+)
     

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

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121. (10 * (10 + 1)) / 2
     

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

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123. •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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124. Instrument your
     programs. Measure
     before making efficiency
     changes.
     

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125. Use variable names
     that mean something.
     

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126. a
     s
     l
     

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127. age
     sex
     location
     

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128. age_over_18?
     

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129. adult?
     

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130. Don’t repeat
     yourself.
     

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131. Parenthesize to
     avoid ambiguity.
     

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132. x || y && z
     

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133. x || (y && z)
     

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134. Keep the code & its
     comments in sync.
     

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

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

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

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

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

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141. # increment counter by 1
     counter += 1
     

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

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143. //
     // 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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144. Fuck this
     shit!!!
     

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145. Style guides
     for
     programming languages
     

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146. Python
     

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

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148. Java
     

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

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

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151. Go
     

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

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153. gofmt
     

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154. View Slide

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

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

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157. View Slide

158. 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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159. View Slide

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

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161. View Slide

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

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163. Languages are always
     evolving
     

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164. Good style practices
     are evolving as well
     

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

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

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167. Style consistency is of
     paramount importance
     

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168. Community
     Personal Project
     Company
     

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169. Community
     Project
     Company
     

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170. Style separates
     the good from the
     great
     

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171. Felina
     

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172. One more thing…
     

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173. View Slide