Ruby Presentation - Beamer

1. The Language Tools Ruby: Why We Love It https://github.com/Kelsin/ruby-presentation Christopher Giroir November 8th, 2011 Christopher Giroir Ruby: Why We Love It

2. The Language Tools 1 The Language Basics Why We Love It Gems 2 Tools Bundler RVM Christopher Giroir Ruby: Why We Love It

3. The Language Tools Basics Overview Inspired by Smalltalk (which I love) Also draws from Perl, Eiﬀel, Ada and LISP Includes a REPL Built for developers as a language they would love to use Dynamic, strict, reﬂective, object oriented Everything is an expression (even statements) Everything is executed imperatively (even declarations) Christopher Giroir Ruby: Why We Love It

10. The Language Tools Basics Object Oriented Everything is an object Single Inheritance Modules can be mixed in Dynamic Dispatch Christopher Giroir Ruby: Why We Love It

14. The Language Tools Basics Simple Code 1 5.times { print "Hello" } This outputs: 1 Hello 2 Hello 3 Hello 4 Hello 5 Hello 6 => 5 Christopher Giroir Ruby: Why We Love It

15. The Language Tools Basics Simple Code 1 5.times { print "Hello" } This outputs: 1 Hello 2 Hello 3 Hello 4 Hello 5 Hello 6 => 5 Christopher Giroir Ruby: Why We Love It

16. The Language Tools Basics Types 1 # Strings 2 s = ’Testing’ 3 4 # Interpreted Strings 5 t = "Double #{str}" 6 7 # Symbols 8 sym = :chris 9 10 # Arrays 11 a = [1,2,3] 12 13 # Hashes 14 h = { :key => ’value’, :chris => ’awesome’ } Christopher Giroir Ruby: Why We Love It

17. The Language Tools Basics Classes 1 class Box 2 def initialize(w,h,d) 3 @width = w 4 @height = h 5 @depth = d 6 end 7 8 def volume 9 @width * @height * @depth 10 end 11 end 12 13 box = Box.new(2,2,2) 14 box.volume # => 8 Christopher Giroir Ruby: Why We Love It

18. The Language Tools Basics Simple Inheritance 1 class JackInTheBox < Box 2 def initialize(msg) 3 @msg = msg 4 super(3,3,3) 5 end 6 7 def open 8 puts @msg 9 end 10 end 11 12 jbox = JackInTheBox.new(’Surprise!’) 13 jbox.volume # => 27 14 jbox.open # prints ’Surprise!’ Christopher Giroir Ruby: Why We Love It

19. The Language Tools Basics Control 1 while true == false 2 if var == 5 3 break 4 end 5 6 begin 7 var - 1 8 end while var < 4 9 10 next if var == 6 11 end Christopher Giroir Ruby: Why We Love It

20. The Language Tools Basics Blocks 1 [1,2,3].each { |n| puts n } This outputs: 1 1 2 2 3 3 4 => [1,2,3] Christopher Giroir Ruby: Why We Love It

21. The Language Tools Basics Blocks 1 [1,2,3].each { |n| puts n } This outputs: 1 1 2 2 3 3 4 => [1,2,3] Christopher Giroir Ruby: Why We Love It

22. The Language Tools Basics Block Syntax 1 5.upto(10) { |n| puts n } This is exactly the same as the following: 1 5.upto(10) do |n| 2 puts n 3 end Christopher Giroir Ruby: Why We Love It

23. The Language Tools Why We Love It Attribute Methods 1 class Person 2 def name 3 @name 4 end 5 def social=(s) 6 @social = s 7 end 8 def age 9 @age 10 end 11 def age=(a) 12 @age = a 13 end 14 end Christopher Giroir Ruby: Why We Love It

24. The Language Tools Why We Love It The Easy Way 1 class Person 2 attr_reader :name 3 attr_writer :social 4 attr_accessor :age 5 end Christopher Giroir Ruby: Why We Love It

25. The Language Tools Why We Love It The Easy Way Explained 1 class Person 2 attr_reader :name 3 attr_writer :social 4 attr_accessor :age 5 end Ruby syntax allows method calls without () Result is clean and looks like a language feature Christopher Giroir Ruby: Why We Love It

26. The Language Tools Why We Love It The Easy Way Explained 1 class Person 2 attr_reader :name 3 attr_writer :social 4 attr_accessor :age 5 end Ruby syntax allows method calls without () Result is clean and looks like a language feature Christopher Giroir Ruby: Why We Love It

27. The Language Tools Why We Love It We can implement this ourselves Untested code, please do not copy: 1 class Object 2 def self.attr_reader(var) 3 class_eval <<-METHODS 4 def #{var} 5 @#{var} 6 end 7 METHODS 8 end 9 end Christopher Giroir Ruby: Why We Love It

28. The Language Tools Why We Love It We can implement this ourselves Untested code, please do not copy: 1 class Object 2 def self.attr_reader(var) 3 class_eval <<-METHODS 4 def #{var} 5 @#{var} 6 end 7 METHODS 8 end 9 end Christopher Giroir Ruby: Why We Love It

29. The Language Tools Why We Love It Why Blocks 1 (map (lambda (n) 2 (+ n 5)) 3 ’(1 2 3)) Becomes: 1 [1,2,3].map do |n| 2 n + 5 3 end Results in: 1 => [6,7,8] Christopher Giroir Ruby: Why We Love It

30. The Language Tools Gems Modules 1 module Voice 2 def say(msg) 3 puts msg 4 end 5 end 6 7 class Person 8 include Voice 9 end 10 11 p = Person.new 12 p.say(’Hello’) # prints ’Hello’ Christopher Giroir Ruby: Why We Love It

31. The Language Tools Gems Using Gems Require loads in ﬁles 1 require ’saver’ # pulls in ’saver.rb’ Gems allow us to not deal with paths 1 require ’rubygems’ 2 require ’saver’ 3 4 class Item 5 include Saver 6 end Christopher Giroir Ruby: Why We Love It

32. The Language Tools Gems Writing Gems 1 Gem::Specification.new do |s| 2 s.name = "saver" 3 s.version = Saver::VERSION 4 s.authors = ["Christopher Giroir"] 5 s.email = ["kelsin@valefor.com"] 6 s.homepage = "http://kelsin.github.com/saver/" 7 8 s.files = ‘git ls-files‘.split("n") 9 s.require_paths = ["lib"] 10 11 s.add_dependency ’activesupport’, ’~> 3.0.0’ 12 s.add_dependency ’mongo_mapper’ 13 end Christopher Giroir Ruby: Why We Love It

33. The Language Tools Bundler Why Bundler? Many projects (i.e. rails apps) are not gems themselves They do have gem dependencies Easy way to install and keep track of these dependencies Making sure ONLY the proper gems are used Christopher Giroir Ruby: Why We Love It

36. The Language Tools Bundler The Gemﬁle 1 source ’http://tools1.savewave.com/rubygems’ 2 source ’http://rubygems.org’ 3 4 gem ’rails’, ’3.0.7’ 5 6 gem ’sw-model’, ’0.13.0’ 7 8 group :development, :test do 9 gem "rspec" 10 end Christopher Giroir Ruby: Why We Love It

37. The Language Tools Bundler Using Bundler 1 # Install the gems from the Gemfile 2 bundle install 3 4 # Update gems to new versions 5 bundle update 6 7 # Execute command with proper gems 8 bundle exec rake spec In your ruby code 1 require "rubygems" 2 require "bundler/setup" 3 require "saver" Christopher Giroir Ruby: Why We Love It

38. The Language Tools Bundler Gemﬁle.lock When you initially install versions are saved to Gemﬁle.lock After they are only updated on bundle update SHOULD be checked into version control Protects from version updates Christopher Giroir Ruby: Why We Love It

41. The Language Tools RVM Why RVM? Different projects might use different versions of rails Different projects might use different ruby interpreters Ruby JRuby Rubinus While bundler helps, complete gem isolation is better! It’s nice to keep your system ruby separate and not update it Christopher Giroir Ruby: Why We Love It

45. The Language Tools RVM Using RVM 1 # Install the default 1.9.2 ruby interpretor 2 rvm install 1.9.2 3 4 # Switch to using 1.9.2 5 rvm use 1.9.2 6 7 # List installed rubies 8 rvm list Christopher Giroir Ruby: Why We Love It

46. The Language Tools RVM RVM Gemsets 1 # Create a new gemset 2 rvm gemset create savingstar-web 3 4 # List gemsets 5 rvm gemset list 6 7 # Switch to a ruby and gemset together 8 rvm use 1.9.2@savingstar-web Christopher Giroir Ruby: Why We Love It

47. The Language Tools RVM .rvmrc A .rvmrc ﬁle per project allows you to say which ruby and gemset to use Should be in source control. Helps RVM users out, ignored for others It’s a shell script that’s executed everytime you cd (very unsafe) Makes life very easy however! 1 rvm use 1.9.2@saveingstar-web --create Christopher Giroir Ruby: Why We Love It

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