Code Charcuterie

My talk on Code Charcuterie from RailsBerry

Transcript

1. ZOMG
   HAPPY FRIDAY!
   

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3. Rails Barry
   

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4. Do you have a Mac?
   Do you have a Wii?
   

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5. DarwiinRemote
   

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6. Aaron Patterson
   

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7. @tenderlove
   

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8. @tenderlove
   TWEET TO ME!
   

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9. aaron.patterson@gmail.com
   

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10. aaron.patterson@gmail.com
    EMAIL TO ME!
    

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11. AT&T, AT&T logo and all AT&T related marks are trademarks of AT&T Intellectual Property and/or AT&T affiliated companies.
    

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12. Señor Software
    Engineer
    

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13. ruby-core
    rails-core
    

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14. WWFMD?
    

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24. AWESOME
    LOGOS
    

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25. STOP IT
    

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28. NOTHING
    

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29. Code
    Charcuterie
    

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30. Amateur
    Charcuterier (sp?)
    

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35. Tight Coupling?
    

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36. Setting Expectations
    

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38. Instrumentation
    Concurrency
    Attributes
    

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39. Number of Doubts
    Chart of Doubts
    

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40. Number of Doubts
    Chart of Doubts
    Few Doubts
    

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41. Number of Doubts
    Chart of Doubts
    Many Doubts
    

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42. Instrumentation
    

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43. Publishing
    ActiveSupport::Notifications.instrument("render") do
    render :text => "Foo"
    end
    

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44. Subscribing
    events = []
    ActiveSupport::Notifications.subscribe("render") do |*e|
    events << e
    end
    

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45. def instrument(name, payload={})
    started = Time.now
    begin
    yield
    ensure
    @notifier.publish(name, started, Time.now, @id, payload)
    end
    end
    

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46. def instrument(name, payload={})
    started = Time.now
    begin
    yield
    ensure
    @notifier.publish(name, started, Time.now, @id, payload)
    end
    end
    Number of Doubts
    

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47. my time + children
    

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48. -> sql executed
    -> view rendered
    Events Received
    

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49. -> sql executed
    -> view rendered
    Events Received
    Number of Doubts
    

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50. Missing Information
    

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51. -> start rendering
    -> start execute SQL
    <- finish execute SQL
    -> start execute SQL
    <- finish execute SQL
    <- finish rendering
    

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52. Rendering
    SQL
    SQL
    

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53. class Listener
    def start(event)
    end
    def finish(event)
    end
    end
    listener = Listener.new
    AS::Notifications.subscribe("render", listener)
    

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54. Evented Publishing
    def instrument(name, payload={})
    @notifier.start(name, @id, payload)
    begin
    yield
    ensure
    @notifier.finish(name, @id, payload)
    end
    end
    

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55. Make it Quack
    class Timed
    def initialize(pattern, delegate)
    @delegate = delegate
    @timestack = Hash.new { |h,id|
    h[id] = Hash.new { |ids,name| ids[name] = [] }
    }
    end
    def start(name, id, payload)
    @timestack[id][name].push Time.now
    end
    def finish(name, id, payload)
    started = @timestack[id][name].pop
    @delegate.call(name, started, Time.now, id, payload)
    end
    end
    

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56. Tiny Factory
    def subscribe(pattern = nil, listener = Proc.new)
    if listener.respond_to?(:call)
    subscriber = Timed.new pattern, listener
    else
    subscriber = listener
    end
    @subscribers << subscriber
    end
    

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57. Our Reward
    

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58. class Indented
    def initialize
    @indentation = 0
    end
    def start name, id, payload
    print indent
    puts "-> #{name} -- #{payload[:virtual_path]}"
    @indentation += 1
    end
    def finish name, id, payload
    @indentation -= 1
    print indent
    puts "<- #{name} -- #{payload[:virtual_path]}"
    end
    private
    def indent
    " " * @indentation
    end
    end
    ActiveSupport::Notifications.notifier.subscribe(nil, Indented.new)
    

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59. -> process_action.action_controller --
    -> render_template.action_view --
    -> !render_template.action_view -- sessions/index
    <- !render_template.action_view -- sessions/index
    <- render_template.action_view --
    -> !render_template.action_view -- layouts/application
    -> render_partial.action_view --
    -> !render_template.action_view -- layouts/_navigation
    <- !render_template.action_view -- layouts/_navigation
    <- render_partial.action_view --
    -> render_partial.action_view --
    -> !render_template.action_view -- sessions/_slim_login
    <- !render_template.action_view -- sessions/_slim_login
    <- render_partial.action_view --
    <- !render_template.action_view -- layouts/application
    <- process_action.action_controller --
    

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61. ml
    !render_template.action_view (4.564 ms)
    virtual_path layouts/application
    render_partial.action_view (0.346 ms)
    identifier /app/views/layouts/_navigation
    render_partial.action_view (0.133 ms)
    identifier /app/views/sessions/_logout.ht
    !render_template.action_view (0.291 ms)
    virtual_path layouts/_navigation
    !render_template.action_view (0.087 ms)
    virtual_path sessions/_logout
    _l
    

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62. tion_controller (0.021 ms)
    MessagesController
    index
    GET
    /messages
    process_action.action_controller (95.463 ms)
    controller MessagesController
    action index
    method GET
    path /messages
    sql.active_record (5.671 ms)
    sql
    SELECT "messages"."id" AS
    t0_r0, "messages"."address_id"
    AS t0_r1, "messages"."from" AS
    t0_r2, "messages"."to" AS
    t0_r3, "messages"."disposable"
    AS t0_r4, "messages"."subject"
    AS t0_r5, "messages"."body" AS
    t0_r6, "messages"."plain" AS
    t0_r7, "messages"."html" AS
    t0_r8, "messages"."created_at"
    AS t0_r9,
    "messages"."updated_at" AS
    t0_r10,
    "messages"."parsed_message_id"
    AS t0_r11, "addresses"."id" AS
    t1_r0, "addresses"."name" AS
    t1_r1, "addresses"."person_id"
    AS t1_r2,
    "addresses"."created_at" AS
    t1_r3,
    "addresses"."updated_at" AS
    t1_r4 FROM "messages" LEFT
    render_template.action_view (63.632 ms)
    identifier /app/views/messages/index.html
    layout layouts/application
    

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63. Concurrency
    

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64. Amdahl's Law
    

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66. laptop = Laptop.new 1
    10.times {
    laptop.execute { sleep(1) }
    }
    

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68. = 1
    

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69. $ time ruby test.rb
    real 0m10.046s
    user 0m0.023s
    sys 0m0.008s
    $
    

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70. laptop = Laptop.new ∞
    10.times {
    laptop.execute { sleep(1) }
    }
    

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72. = 10
    

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73. $ time ruby test.rb
    real 0m1.033s
    user 0m0.023s
    sys 0m0.008s
    $
    

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74. Modeling Our
    Machine
    

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75. class Sleeper
    def run; sleep(1); end
    end
    q = Queue.new
    10.times { q.push Sleeper.new }
    10.times { q.push nil }
    # 10 cores! wow!
    10.times.map {
    Thread.new {
    while obj = q.pop
    obj.run
    end
    }
    }.each(&:join)
    

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76. What is my P?
    

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77. class Sleeper
    def run; sleep(1); end
    end
    q = SlowQueue.new # make `pop` cost more
    10.times { q.push Sleeper.new }
    10.times { q.push nil }
    # 10 cores! wow!
    10.times.map {
    Thread.new {
    while obj = q.pop
    obj.run
    end
    }
    }.each(&:join)
    

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78. $ time ruby test.rb
    real 0m2.153s
    user 0m0.027s
    sys 0m0.012s
    

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79. Hidden Sequential
    Code
    

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80. Starvation
    

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81. Scarce Resources
    

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83. ME EBI
    

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84. ME EBI
    

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85. Connection Pool
    

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86. Connections Are Not
    Thread Safe
    

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87. One to One
    

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88. One to One
    Number of Doubts
    

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89. pool.connection
    pool = ActiveRecord::Base.connection_pool
    p pool.connection.object_id # => 1234
    p pool.connection.object_id # => 1234
    

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90. Starvation
    5.times {
    Thread.new { pool.connection }
    }
    Thread.new { pool.connection }
    

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91. Starvation
    5.times {
    Thread.new { pool.connection }
    }
    Thread.new { pool.connection }
    

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92. Queueing
    

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93. Splitting Work
    cpu_queue = Queue.new
    io_queue = Queue.new
    5.times {
    Thread.new { io_queue.pop.run }
    }
    10.times {
    Thread.new { cpu_queue.pop.run }
    }
    

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94. Consumer
    class Saver
    def initialize(record)
    @record = record
    end
    def run
    @record.save!
    end
    end
    

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95. Producer
    class CreatePost
    def initialize(q)
    @q = q
    end
    def run
    post = Post.new(:name => 'aaron')
    @q.push SavePost.new(post)
    end
    end
    

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97. Parallel CPU
    def fib n
    if n < 3
    1
    else
    fib(n-1) + fib(n-2)
    end
    end
    2.times.map { fib(34) }
    

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98. $ time ruby test.rb
    real 0m3.315s
    user 0m3.264s
    sys 0m0.010s
    

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99. 2.times.map {
    Thread.new { fib(34) }
    }.each(&:join)
    Parallelize
    

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100. Caught in the GIL
     $ time ruby test.rb
     real 0m4.825s
     user 0m3.823s
     sys 0m1.978s
     

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101. Slow I/O Server
     server = GenericServer.new('127.0.0.1')
     server.start do |socket|
     sleep 0.5
     socket.print "HELLO"
     socket.close
     end
     

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102. TCP Client
     require 'socket'
     5.times.map {
     sock = TCPSocket.new '127.0.0.1', 28561
     puts sock.read
     }
     

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103. $ time ruby client.rb
     HELLO
     HELLO
     HELLO
     HELLO
     HELLO
     real 0m2.546s
     user 0m0.026s
     sys 0m0.009s
     

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104. require 'socket'
     5.times.map {
     Thread.new {
     sock = TCPSocket.new '127.0.0.1', 28561
     puts sock.read
     }
     }.each(&:join)
     Parallelize
     

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105. $ time ruby client.rb
     HELLO
     HELLO
     HELLO
     HELLO
     HELLO
     real 0m0.552s
     user 0m0.028s
     sys 0m0.009s
     

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106. Sending Email!
     

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107. class UserController < ApplicationController
     def create
     user = User.create!(params[:user])
     UserMailer.deliver_welcome_email(user)
     end
     end
     

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108. class UserController < ApplicationController
     def create
     user = User.create!(params[:user])
     UserMailer.deliver_welcome_email(user)
     end
     end
     

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109. class UserController < ApplicationController
     def create
     user = User.create!(params[:user])
     UserMailer.deliver_welcome_email(user)
     end
     end
     Number of Doubts
     

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110. class MailSender
     def initialize(id)
     @id = id
     end
     def run
     user = User.find(@id)
     UserMailer.deliver_welcome_email(user)
     end
     end
     

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111. class UserController < ApplicationController
     def create
     user = User.create!(params[:user])
     mail_queue.push MailSender.new(user.id)
     end
     end
     

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112. Thread.new {
     loop do
     mail_queue.pop.run
     }
     }
     

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114. Outside the loop
     More Parallel
     

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115. You are
     ENCOURAGED
     to use threads
     

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116. I/O can be parallelized
     CPU cannot
     * in MRI
     

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117. Attribute Accessors
     

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118. Attribute Access
     post = Post.new(:title => 'hello!')
     post.title # => 'hello!'
     post.respond_to?(:title) # => true
     

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119. Lazily Defined
     begin
     p Post.instance_method(:name)
     rescue NameError
     puts "oh no!"
     end
     Post.new(:name => 'aaron')
     p Post.instance_method(:name)
     

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120. Output
     $ ruby -I lib:test test/cases/argh.rb
     oh no!
     #)#__temp__>
     

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121. Definition Time
     def method_missing(method, *args, &block)
     unless self.class.attribute_methods_generated?
     self.class.define_attribute_methods
     ...
     end
     end
     def respond_to?(name, include_private = false)
     unless self.class.attribute_methods_generated?
     self.class.define_attribute_methods
     end
     super
     end
     

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122. Who called
     respond_to?
     {:method=>"name="}
     ##########################################################################################
     lib/active_record/attribute_assignment.rb:81:in `block in assign_attributes'
     lib/active_record/attribute_assignment.rb:78:in `each'
     lib/active_record/attribute_assignment.rb:78:in `assign_attributes'
     lib/active_record/base.rb:498:in `initialize'
     test/cases/argh.rb:16:in `new'
     test/cases/argh.rb:16:in `'
     ##########################################################################################
     {:method=>"_run__1290908416815974468__initialize__2045902499019596289__callbacks"}
     ##########################################################################################
     lib/active_support/callbacks.rb:398:in `__run_callback'
     lib/active_support/callbacks.rb:385:in `_run_initialize_callbacks'
     lib/active_support/callbacks.rb:81:in `run_callbacks'
     lib/active_record/base.rb:501:in `initialize'
     test/cases/argh.rb:16:in `new'
     test/cases/argh.rb:16:in `'
     ##########################################################################################
     Number of Doubts
     

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123. after_initialize
     class Subject < ActiveRecord::Base
     after_initialize :set_email_address
     protected
     def set_email_address
     ...
     end
     end
     

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124. use super
     class Subject < ActiveRecord::Base
     def initialize(*args)
     super
     set_email_address # after_init
     end
     protected
     def set_email_address
     ...
     end
     end
     Number of Doubts
     

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125. DO IT AGAIN!
     10.times {
     Post.new(:name => 'aaron')
     }
     

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126. What method?
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     {:method=>"name="}
     {:method=>"_run__1048083580144971540__initialize__3082064574212577540__callbacks"}
     Number of Doubts
     

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127. Define Methods
     def define_attribute_methods
     ....
     @attribute_methods_mutex.synchronize do
     return if attribute_methods_generated?
     superclass.define_attribute_methods unless self == base_class
     super(column_names)
     column_names.each { |name| define_external_attribute_method(name) }
     @attribute_methods_generated = true
     end
     end
     

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128. Define Methods
     def define_attribute_methods
     ....
     @attribute_methods_mutex.synchronize do
     return if attribute_methods_generated?
     superclass.define_attribute_methods unless self == base_class
     super(column_names)
     column_names.each { |name| define_external_attribute_method(name) }
     @attribute_methods_generated = true
     end
     end
     wtf???
     

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129. RAWWWRRRR
     class A
     def hi(stuff)
     end
     end
     class B < A
     def hi
     super(%w{ problem? })
     end
     end
     

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130. :'(
     def calls_hi(obj)
     obj.hi(%w{ how are you? })
     end
     calls_hi(A.new) # => OK!
     calls_hi(B.new) # => Boom!
     

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131. IF
     THEN
     B is an A
     B can be used as an A
     

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132. Number of Doubts
     

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133. define_attribute_methods
     

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134. ActiveModel
     

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135. define_attribute_methods
     def define_attribute_methods(attr_names)
     attr_names.each { |attr_name|
     define_attribute_method(attr_name)
     }
     end
     

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136. define_attribute_methods
     def define_attribute_methods(attr_names)
     attr_names.each { |attr_name|
     define_attribute_method(attr_name)
     }
     end
     THANKS
     ACTIVE MODEL
     

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137. define_attribute_method
     def define_attribute_method(attr_name)
     ...
     unless instance_method_already_implemented?(method_name)
     generate_method = "define_method_#{matcher.method_missing_target}"
     if respond_to?(generate_method, true)
     send(generate_method, attr_name)
     else
     define_optimized_call generated_attribute_methods, method_name,
     matcher.method_missing_target, attr_name.to_s
     end
     end
     end
     

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138. define_attribute_method
     def define_attribute_method(attr_name)
     ...
     unless instance_method_already_implemented?(method_name)
     generate_method = "define_method_#{matcher.method_missing_target}"
     if respond_to?(generate_method, true)
     send(generate_method, attr_name)
     else
     define_optimized_call generated_attribute_methods, method_name,
     matcher.method_missing_target, attr_name.to_s
     end
     end
     end
     

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139. define_attribute_method
     def define_attribute_method(attr_name)
     ...
     unless instance_method_already_implemented?(method_name)
     generate_method = "define_method_#{matcher.method_missing_target}"
     if respond_to?(generate_method, true)
     send(generate_method, attr_name)
     else
     define_optimized_call generated_attribute_methods, method_name,
     matcher.method_missing_target, attr_name.to_s
     end
     end
     end
     

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140. define_attribute_method
     def define_attribute_method(attr_name)
     ...
     unless instance_method_already_implemented?(method_name)
     generate_method = "define_method_#{matcher.method_missing_target}"
     if respond_to?(generate_method, true)
     send(generate_method, attr_name)
     else
     define_optimized_call generated_attribute_methods, method_name,
     matcher.method_missing_target, attr_name.to_s
     end
     end
     end
     

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141. define_attribute_method
     def define_attribute_method(attr_name)
     ...
     unless instance_method_already_implemented?(method_name)
     generate_method = "define_method_#{matcher.method_missing_target}"
     if respond_to?(generate_method, true)
     send(generate_method, attr_name)
     else
     define_optimized_call generated_attribute_methods, method_name,
     matcher.method_missing_target, attr_name.to_s
     end
     end
     end
     

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142. WHY AREN'T THEY
     ALL OPTIMIZED????
     

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143. define_method_attribute
     define_method_attribute=
     define_method_attribute_before_type_cast
     define_method_attribute?
     define_method_attribute_changed?
     define_method_attribute_change
     define_method_attribute_will_change!
     define_method_attribute_was
     define_method_reset_attribute!
     define_method__attribute
     define_method_attribute
     define_method_attribute=
     define_method_attribute_before_type_cast
     define_method_attribute?
     define_method_attribute_changed?
     define_method_attribute_change
     define_method_attribute_will_change!
     define_method_attribute_was
     define_method_reset_attribute!
     define_method__attribute
     

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144. define_method_attribute
     define_method_attribute=
     define_method_attribute_before_type_cast
     define_method_attribute?
     define_method_attribute_changed?
     define_method_attribute_change
     define_method_attribute_will_change!
     define_method_attribute_was
     define_method_reset_attribute!
     define_method__attribute
     define_method_attribute
     define_method_attribute=
     define_method_attribute_before_type_cast
     define_method_attribute?
     define_method_attribute_changed?
     define_method_attribute_change
     define_method_attribute_will_change!
     define_method_attribute_was
     define_method_reset_attribute!
     define_method__attribute
     

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145. define_method_attribute
     define_method_attribute=
     define_method_attribute_before_type_cast
     define_method_attribute?
     define_method_attribute_changed?
     define_method_attribute_change
     define_method_attribute_will_change!
     define_method_attribute_was
     define_method_reset_attribute!
     define_method__attribute
     define_method_attribute
     define_method_attribute=
     define_method_attribute_before_type_cast
     define_method_attribute?
     define_method_attribute_changed?
     define_method_attribute_change
     define_method_attribute_will_change!
     define_method_attribute_was
     define_method_reset_attribute!
     define_method__attribute
     

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146. define_method_attribute
     define_method_attribute=
     define_method_attribute_before_type_cast
     define_method_attribute?
     define_method_attribute_changed?
     define_method_attribute_change
     define_method_attribute_will_change!
     define_method_attribute_was
     define_method_reset_attribute!
     define_method__attribute
     define_method_attribute
     define_method_attribute=
     define_method_attribute_before_type_cast
     define_method_attribute?
     define_method_attribute_changed?
     define_method_attribute_change
     define_method_attribute_will_change!
     define_method_attribute_was
     define_method_reset_attribute!
     define_method__attribute
     THANKS
     ACTIVE MODEL
     

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147. Number of Doubts
     

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148. Side Note:
     Does anyone USE this?
     

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149. Side Note:
     Should you use this?
     

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150. Where were we?
     

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151. Post.new
     respond_to?
     AR define_attr_methods
     AM define_attr_methods
     AM define_attr_method
     AR define_method_attr
     

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152. In VIM
     •Ctrl-]
     •Ctrl-o
     •:help ctags
     

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153. def define_method_attribute(attr_name)
     generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
     def __temp__
     #{internal_attribute_access_code(attr_name, attribute_cast_code(attr_name))}
     end
     alias_method '#{attr_name}', :__temp__
     undef_method :__temp__
     STR
     end
     

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154. method(:name).source
     

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155. Type Cast
     Value Lookup
     post.method(:title).source
     

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156. Post#name
     def name
     attr_name = 'name'
     unless @attributes.has_key?(attr_name)
     missing_attribute(attr_name, caller)
     end
     v = @attributes[attr_name] && v
     end
     

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157. Post#name
     def name
     attr_name = 'name'
     unless @attributes.has_key?(attr_name)
     missing_attribute(attr_name, caller)
     end
     v = @attributes[attr_name] && v
     end
     SEEMS
     LEGIT
     

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158. Post#created_at
     def created_at
     attr_name = 'created_at'
     unless @attributes.has_key?(attr_name)
     @attributes_cache[attr_name] ||= (missing_attribute(attr_name, caller)
     end
     (v=@attributes[attr_name]) &&
     ActiveRecord::ConnectionAdapters::SQLiteColumn.string_to_time(v))
     end
     

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159. Post#created_at
     def created_at
     attr_name = 'created_at'
     unless @attributes.has_key?(attr_name)
     @attributes_cache[attr_name] ||= (missing_attribute(attr_name, caller)
     end
     (v=@attributes[attr_name]) &&
     ActiveRecord::ConnectionAdapters::SQLiteColumn.string_to_time(v))
     end
     DOUBTS
     INCREASING
     

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160. attribute_cast_code
     def attribute_cast_code(attr_name)
     columns_hash[attr_name].type_cast_code('v')
     end
     

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161. type_cast_code
     def type_cast_code(var_name)
     klass = self.class.name
     case type
     when :string, :text then var_name
     when :integer then "(#{var_name}.to_i rescue #{var_name} ? 1 : 0)"
     when :float then "#{var_name}.to_f"
     when :decimal then "#{klass}.value_to_decimal(#{var_name})"
     when :datetime, :timestamp then "#{klass}.string_to_time(#{var_name})"
     when :time then "#{klass}.string_to_dummy_time(#{var_name})"
     when :date then "#{klass}.string_to_date(#{var_name})"
     when :binary then "#{klass}.binary_to_string(#{var_name})"
     when :boolean then "#{klass}.value_to_boolean(#{var_name})"
     else var_name
     end
     end
     

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162. type_cast
     def type_cast(value)
     return nil if value.nil?
     return coder.load(value) if encoded?
     klass = self.class
     case type
     when :string, :text then value
     when :integer then value.to_i rescue value ? 1 : 0
     when :float then value.to_f
     when :decimal then klass.value_to_decimal(value)
     when :datetime, :timestamp then klass.string_to_time(value)
     when :time then klass.string_to_dummy_time(value)
     when :date then klass.string_to_date(value)
     when :binary then klass.binary_to_string(value)
     when :boolean then klass.value_to_boolean(value)
     else value
     end
     end
     

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163. Number of Doubts
     

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164. Number of Doubts
     TOO MANY!
     

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165. HOWTO FIX?
     

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166. What do we want?
     •Less dynamic code
     •Consistent method definitions
     •Matching speed (even on read_attribute)
     

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167. What does it do?
     •Attribute lookup
     •Column lookup
     •Value typecasting
     •Typecast value caching
     

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168. def read_attribute(attr_name)
     # If it's cached, just return it
     @attributes_cache.fetch(attr_name.to_s) { |name|
     column = @columns_hash[name]
     value = @attributes.fetch(name) {
     return attribute_missing(name, caller)
     }
     # Cache if we're supposed to
     if self.class.cache_attribute?(name)
     @attributes_cache[name] = column.type_cast(value)
     else
     column.type_cast value
     end
     }
     end
     

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169. def name
     read_attribute 'name'
     end
     Post#name
     

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170. def created_at
     read_attribute 'created_at'
     end
     Post#created_at
     

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171. BONUS FEATURE!
     Post.select('true as hi').first.hi # => true
     

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174. Clean Code
     IS A FEATURE
     

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175. Don't throw out the baby
     with the bathwater!
     

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176. Questions?
     ὑ ὑ ὑ ὑ ὑ ὑ
     

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