The TImeless Way of Building - RevConf 2017

"Design patterns" is a common phrase that is often spoken in the course of design and development of web applications. But it's genesis is not from programming, but Architecture. Through a lack of understanding, they are misused and abused. We're going to rectify that misunderstanding.

Transcript

1. BUILDING THE TIMELESS WAY OF REVOLUTION CONF 2017 VIRGINIA BEACH, VIRGINIA John Athayde @boboroshi
2. I’m Jean Valjean. WHO AM I?
4. METICULOUS
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 2 4DESIGN PATTERNS
13. 1PATTERN NAME
14. 2THE 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. foreach
21. for x in…
22. Patterns?
26. The Three-book series
27. “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:
29. 1 3 2 4 ARCHITECTURE PATTERN: transition space between the 
 street and the front door
31. PRINCIPLES
 ARE PATTERNS
32. DRY
33. YAGNI
34. SRP SINGLE RESPONSIBILITY PRINCIPLE
35. OCP OPEN/CLOSED PRINCIPLE
36. LSP LISKOV SUBSTITUTION PRINCIPLE
37. ISP INTERFACE SEGREGATION PRINCIPLE
38. DIP Dependency inversion PRINCIPLE
39. S O L I D SRP OCP LSP ISP DIP
40. PATTERNS ALL THE WAY DOWN
41. WHERE DO PATTERNS COME FROM? ARCHITECTURE
42. 1570 ITALY
49. 1750 LONDON
55. 1773 LONDON
63. WORKING WITHIN THE LANGUAGE OF CLASSICAL ARCHITECTURE.
64. “…[Architecture and Software patterns] give us a vocabulary to talk about how things are constructed. It is much more convenient to say, ‘this object has listeners for its properties,’ than ‘this object lets you hook callback functions that are called when properties change.’” — Federico Mena Quintero
 “Software that has the Quality Without a Name”
66. Phi Beta Kappa Hall, Wren Building, William & Mary, Wiliamsburg, Virginia
70. http://www.flickr.com/photos/cindy47452/3682879190/
71. THE LANGUAGE WE USE TO DESCRIBE OURSELVES
72. craftSmen
73. ENGINEERS
74. architects
75. BUILDERS W E F A N C Y O U R S E L V E S
76. “Engineers frequently have to make decisions of great practical consequence in the face of incomplete and uncertain knowledge.” — Walter Vincenti ON ENGINEERS:
77. PROBLEM: too many people think that “design patterns” in software means a library of Code templates.
78. “ design patterns are suggested approaches seen in the wild. - B R I A N H O G A N ”
79. http://www.patterntap.com
80. STRIVING SO WHAT ARE WE TOWARDS?
81. HAS NO NAME THE QUALITY OF A SPACE that
83. Gibellina, Italy
84. Gibellina Nuova, Italy
85. Charlottesville Downtown
86. Shops at Stonefield
87. “…the mere list of elements which are typical in a given town tells us the way of life of people there.” — Alexander, TTWoB, pp71
88. “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
89. Objective Quality THIS IS AN
91. Nature = 15 Properties in common All patterns come from these properties Each property can also transform Only good design = transformation,
 one property at a time.
93. Thick Boundaries Local Symmetries Positive Space
94. TRANSFORMATION STRUCTURE-PRESERVING
95. REFACTORING
96. WELCOME TO NEGATIVE TOWN ANTIPATTERNS
97. D
99. Gibellina Nuova, Italy D
100. “Big Ball of Mud” Paper (aka Shanty Towns) D
101. D
102. Walking the Tree D
103. @account.customer.address.state D
104. class Customer < ActiveRecord::Base has_one :address has_one :account ... def state address.state end ... end @account.customer.state 2
105. 2 COMPOSITION DELEGATE
106. FAT Models D
107. MODULES CONCERNS PLUGINS* GEMS ENGINES 2
108. FAT Controllers ONE CONTROLLER TO RULE THEM ALL... or not. D
109. TRANSACTIONALS before_validation before_validation on: :create after_validation after_validation on: :create before_save before_action after_save after_action 2 D
110. http://callbackhell.com D fs.readdir(source, function (err, files) { if (err) { console.log('Error finding files: ' + err) } else { files.forEach(function (filename, fileIndex) { console.log(filename) gm(source + filename).size(function (err, values) { if (err) { console.log('Error identifying file size: ' + err) } else { console.log(filename + ' : ' + values) aspect = (values.width / values.height) widths.forEach(function (width, widthIndex) { height = Math.round(width / aspect) console.log('resizing ' + filename + 'to ' + height + 'x' + height) this.resize(width, height).write(dest + 'w' + width + '_' + filename, function(err) { if (err) console.log('Error writing file: ' + err) }) }.bind(this)) } }) }) } }) CALLBACKS
111. Keep Your Code Shallow MODULARIZE (Make a library) handle every single error 2 http://callbackhell.com
112. “I USE (DRUPAL|RAILS|FRAMEWORK.NAME) TO BUILD EVERYTHING.” D
113. FRAMEWORKS ARE
 A SERIES OF VERY LARGE TUBES LIBRARIES 2 D
114. 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
115. rails g model {modelname} D
116. DSL ALL THE THINGS D
117. DIV-itis PHP-itis Java-isms D
118. M V C 2
119. LOTS OF VIEW LOGIC D
120. 2 TYPOGRAPHIC REFACTORING http://naildrivin5.com/blog/2013/05/17/source-code-typography.html
121. def text_field_tag(name, value = nil, options = {}) tag :input, { :type => "text", :name => name, :id => sanitize_to_id(name), :value => value }.update( end def text_field_tag(name, value = nil, options = {}) tag :input, { :type => "text", :name => name, :id => sanitize_to_id(name), :value => value }.update(options.stringify_keys) end 2 D
122. Untested Code D
123. SAMPLE EXAMPLE REFACTOR TRACTOR
125. PHONE CALL
126. HALF CALL HALF CALL Gerard Meszaros “Pattern; Half Object + Protocol”
127. HALF CALL HALF CALL Gerard Meszaros “Pattern; Half Object + Protocol”
128. HALF CALL HALF CALL cALL
129. HALF CALL HALF CALL HALF CALL cALL
130. REFACTOR NOT THE GREAT REWRITE
131. SO WHAT DO WE DO? THE KERNEL OF THE WAY
133. “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
134. “ 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 ”
135. “...mediocre developers never even ask why. They just arrive at the first solution that works and keep plowing ahead.” — Jeff Atwood, c.2005
136. PATTERNS THEREFORE REMEMBER THAT IT’S NOT ABOUT USING
137. LANGUAGE it’s about speaking a
139. LET’S GO THEORY! AND YET…
140. HAS NO NAME THE QUALITY OF A SPACE that
141. “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
142. “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
143. “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
144. “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.” — The Timeless Way of Building, Chapter 27
145. “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
146. “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
147. REFACTORING STRUCTURE-PRESERVING TRANSFORMATIONS =
148. LANGUAGE LEARN TO speak THE
149. EVOLVES SOFTWARE THAT
150. HAS NO NAME THE QUALITY OF SOFTWARE that
152. The Three-book series
153. @boboroshi THANK YOU john@meticulous.com https://speakerdeck.com/boboroshi SLIDE DECK AVAILABLE: