The Timeless Way of Building (MWRC)

Mountain West Ruby Conference (March 2014) presentation

Transcript

1. BUILDING THE TIMELESS WAY OF John Athayde MOUNTAIN WEST RUBY CONFERENCE MARCH 2014
2. I’m Jean Valjean. WHO AM I?
7. Get our bearings here... WHAT WE’RE GONNA COVER
8. PATTERNS ARCHITECTURE 
 PATTERN LANGUAGES & HISTORY ANTI-PATTERNS APPLY some THEORY
9. LET’S GET ON THE SAME PAGE “PATTERNS”
11. A design pattern systematically names, motivates, and explains a general design that addresses a recurring design problem in object-oriented systems. ! It describes the problem, the solution, when to apply the solution, and its consequences. ! It also gives implementation hints and examples. ! The solution is a general arrangement of objects and classes that solve the problem. The solution is customized and implemented to solve the problem in a particular context.
12. 1 3 2 4 DESIGN PATTERNS
13. 1PATTERN NAME
14. 2 The Problem
15. 3The solution
16. 4consequences
17. “Design patterns help you identify less-obvious abstractions and the objects than can capture them. For example, objects that represent a process or algorithm don’t occur in nature, yet they are a crucial part of flexible designs.”
18. Iterator Pattern Iterate over elements of a collection without exposing the internals...
19. .each
20. Patterns?
24. The Three-book series
25. “How can you distribute responsibility for design through all levels of a large hierarchy, while still maintaining consistency and harmony of overall design?” — M. J. Dominus 2002 ALEXANDER’S QUEST:
27. 1 3 2 4 ARCHITECTURE PATTERN: transition space between the 
 street and the front door
29. PRINCIPLES
 ARE PATTERNS
30. DRY
31. YAGNI
32. SRP SINGLE RESPONSIBILITY PRINCIPLE
33. OCP OPEN/CLOSED PRINCIPLE
34. LSP LISKOV SUBSTITUTION PRINCIPLE
35. ISP INTERFACE SEGREGATION PRINCIPLE
36. DIP Dependency inversion PRINCIPLE
37. S O L I D SRP OCP LSP ISP DIP
38. WHERE DID PATTERNS COME FROM? ARCHITECTURE
52. WORKING WITHIN THE LANGUAGE OF CLASSICAL ARCHITECTURE.
58. http://www.flickr.com/photos/cindy47452/3682879190/
59. crafstmen
60. ENGINEERS
61. architects
62. BUILDERS W E F A N C Y O U R S E L V E S
63. “Engineers frequently have to make decisions of great practical consequence in the face of incomplete and uncertain knowledge.” — Walter Vincenti ON ENGINEERS:
64. PROBLEM: too many people think that “design patterns” in software means a library of Code templates.
65. http://www.patterntap.com
66. “ design patterns are suggested approaches seen in the wild. - B R I A N H O G A N ”
67. STRIVING SO WHAT ARE WE TOWARDS?
68. HAS NO NAME THE QUALITY OF A SPACE that
69. Gibellina, Italy
70. Gibellina Nuova, Italy
71. Welcome to negative town. ANTIPATTERNS
72. D
74. Gibellina Nuova, Italy D
75. “Big Ball of Mud” Paper (aka Shanty Towns) D
76. D
77. Walking the Tree D
78. @account.customer.address.state D
79. class Customer < ActiveRecord::Base has_one :address has_one :account ! ... ! def state address.state end ! ... ! end ! @account.customer.state 2
80. 2 COMPOSITION DELEGATE
81. FAT Models D
82. MODULES CONCERNS PLUGINS* GEMS ENGINES 2
83. CALLBACKS ! before_validation before_validation on: :create after_validation after_validation on: :create before_save before_create after_create after_save 2 D
84. RAILS IS A SERIES OF VERY LARGE TUBES LIBRARIES 2 D
85. class RemoteProcess < ActiveRecord::Base scope :running, where(:state => ‘Running’) scope :system, where(:owner => [‘root’, ‘mysql’]) scope :sorted, order(“percent_cpy desc”) scope :top, lamda {|1| limit(1)} end ! RemoteProcess.running.sorted.top(10) RemoteProcess.running.system.sorted.top(5) sample from Rails Antipatterns pp 37 2
86. rails g model {modelname} D
87. DSL ALL THE THINGS D
88. DIV-itis PHP-itis Java-isms D
89. 2 TYPOGRAPHIC REFACTORING http://naildrivin5.com/blog/2013/05/17/source-code-typography.html
90. M V C 2
91. Untested Code D
92. FAT Controllers ONE CONTROLLER TO RULE THEM ALL... or not. D
94. So what do we do? THE KERNEL OF THE WAY
95. “ design patterns are suggested approaches seen in the wild. - B R I A N H O G A N ” T H I S B E A R S R E P E A T I N G :
97. “The best way to learn to write simple code is to write simple code! Patterns, like all forms of complexity, should be avoided until they are absolutely necessary. That’s the first thing beginners need to learn. Not the last thing. ” — Jeff Atwood c. 2005
98. “ You cannot say that you are correctly applying a design pattern unless you are confronting the problem that the pattern is supposed to solve – R U S S O L S E N ”
99. “...mediocre developers never even ask why. They just arrive at the first solution that works and keep plowing ahead.” — Jeff Atwood, c.2005
100. PATTERNS THEREFORE REMEMBER THAT IT’S NOT ABOUT USING
101. LANGUAGE it’s about speaking a
103. Let’s go theory! AND YET...
104. HAS NO NAME THE QUALITY OF A SPACE that
105. “To many software-patterns folk the quality without a name doesn’t apply to things like software anyhow. I agree that most software —at least the software I see—doesn’t have such a quality, but does that mean it couldn’t? I find it odd, though, to take so much inspiration from the simple, mechanical parts of a person’s work—the form of the pattern language and terms like forces—but to ignore the heart of it. I’m not so sure the quality without a name is irrelevant.” — Richard P. Gabriel Patterns of Software, pp 71
106. HAS NO NAME THE QUALITY OF A SPACE that
107. “Indeed this ageless character has nothing, in the end, to do with languages. The language, and the processes which stem from it, merely release the fundamental order which is native to us.” — The Timeless Way of Building, Chapter 27
108. “They do not teach us, they only remind us of what we know already, and of what we shall discover time and time again, when we give up our opinions, and do exactly what emerges from ourselves.” — The Timeless Way of Building, Chapter 27
109. “To make a building egoless, the builder must let go of all his willful images, and start with 
 a void. You are able to do this only when you no longer fear that nothing will happen, and you can therefore afford to let go of your images. At this stage, the building’s life will come directly from your language.” — The Timeless Way of Building, Chapter 27
110. “Yet , at the very moment when you first relax, and let the language generate the buildings in your mind, you will begin to see how limited your language is. One place can have good patterns in it and be dead. Another place can be without the patterns which apply to it, and yet still be alive. ” — The Timeless Way of Building, Chapter 27
111. “The pattern ALCOVE–which first functioned as an intellectual crutch–is no longer necessary to you. You see reality directly, like an animal. You make the alcove as an animal might make an alcove–not because of the concept– but directly, simply because it is appropriate.” — The Timeless Way of Building, Chapter 27
113. The Three-book series
114. @boboroshi | @therailsview THANK YOU AthaydeWilliamsRailsView BOOK CODE FOR 25% OFF AT www.pragprog.com/titles/warv: john@meticulous.com