Brief Ruby/Ruby on Rails intro

Transcript

1. RUBY
   A PROGRAMMER’S BEST FRIEND
   

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2. Background
   

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3. Yukihiro “Matz” Matsumoto
   

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4. I hope to see Ruby help every programmer in
   the world to be productive, and to enjoy
   programming, and to be happy. at is the
   primary purpose of Ruby language.”
   “
   

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5. - Programmer happiness
   - Principle of least astonishment
   - Human readable
   - Beautiful syntax
   Principles
   

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6. - RubyGems, Bundler & Rake
   - Multiple implementations (MRI, JRuby,
   Rubinius, mruby, MacRuby, Topaz, …)
   - Solid Standard Library
   Ecosystem
   

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7. - MINASWAN
   - Self re ective
   - Open
   - Quirky
   Community
   

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8. The Language
   A Sales Pitch
   

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10. Object–oriented
    1
    

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11. 5.times { print "We love Ruby" }
    

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12. class Animal
    def eat(food)
    puts "Animal eating"
    end
    end
    my_animal = Animal.new
    animal.eat
    # => "Animal eating"
    

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13. class Dog < Animal
    def eat(food)
    puts "Dog eating"
    super
    end
    end
    

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14. module Stomach
    def digest(food)
    # ...
    end
    end
    

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15. class Dog < Animal
    include Stomach
    end
    my_dog = Dog.new
    dog.digest
    

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16. -199.abs
    # => 199
    "Foobar".split("").uniq.sort.join
    # => "abFor"
    nil.class
    # => "NilClass"
    

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17. Dynamically typed
    Duck–typing
    2
    

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18. if dog.is_a? Animal
    dog.eat
    end
    dog.eat if dog.respond_to?(:eat)
    

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19. Monkey–patching
    (Duck–punching)
    3
    

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20. … if it walks like a duck and talks like a
    duck, it’s a duck, right? So if this duck is not
    giving you the noise that you want, you’ve
    got to just punch that duck until it returns
    what you expect.”
    “
    

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21. class String
    def yell
    "#{self.upcase}!"
    end
    end
    "hello".yell
    # => "HELLO!"
    

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22. Meta–programming
    4
    

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23. class Greeter
    def method_missing(name, *args)
    name = name.to_s
    if name =~ /^hello_/
    puts "Hello, #{name.gsub(/^hello_/, '')}!"
    else
    super
    end
    end
    end
    Greeter.new.hello_john
    # => "Hello, john!"
    

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24. Blocks & Lambdas
    5
    

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25. [1, 2, 3].map { |i| i ** 2 }
    # => [1, 4, 9]
    

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26. def greet(&block)
    # ...
    greeting = yield("John")
    # ...
    end
    greet do |name|
    "Hello, #{name}!"
    end
    

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27. A word on speed
    

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28. Ruby on Rails
    An (even shorter) sales pitch
    

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30. - Open Source Web Framework
    - MVC
    - Convention over Con guration
    - DRY
    - Opinionated
    Principles
    

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31. - Generators
    - ORM
    - Restful routing
    - Included webserver
    Features
    

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32. $ gem install rails
    $ rails new blog
    $ cd blog
    $ rails generate scaffold post title content:text
    $ rake db:migrate
    $ rails server
    

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33. author = Author.find_by :name => "John"
    author.posts.first.title
    

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34. Book.where(:title => 'Tale of Two Cities')
    .first_or_create
    

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35. class Account < ActiveRecord::Base
    # Returns all accounts with unread messages.
    def self.with_unread_messages
    joins(:messages).merge(Message.unread)
    end
    end
    

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