1. Ruby on Rails 101.2

2. WTF? Created by Matz in 1993 Inspired by Smalltalk Rubygems = CSPAN Rake = ant Rdoc = javadoc

3. http://rubyurl.com/D1LA

4. How its like Java Object orientated Supports single inheritance Has exceptions Runs on multiple OS’s Runs on Java runtime (using jruby)

5. How it differs Loosely typed until assigned Supports closures / passing blocks Supports ‘modular’ design (mixins) Poor language level support for mulit- threaded execution No primitives (int, float etc)

6. When might you use it?

7. YARJC: Yet another Rails vs. Java Comparison Justin Gehtland recently tried re- implementing one of his web applications in Ruby on Rails instead of his normal Java Spring/Hibernate setup, according to a Slashdot post. http://www.theserverside.com/news/thread.tss?thread_id=33120

8. YARJC: Yet another Rails vs. Java Comparison Justin Gehtland recently tried re- implementing one of his web applications in Ruby on Rails instead of his normal Java Spring/Hibernate setup, according to a Slashdot post. http://www.theserverside.com/news/thread.tss?thread_id=33120 Convention over configuration

9. Setup http://www.rubyonrails.org/down http://www.sqlite.org/ –The version that comes with Leopard isn't high enough. You'll need to get he source and make / sudo make install. Then run 'gem install sqlite3- ruby' (all on the mac). The binaries should do for windows. http://download.netbeans.org/netbeans/6.0/fin al/ http://subversion.tigris.org/project_packages. html

10. Resources http://groups.google.com/group/ruby_ire land/web/rails-resourceshttp://groups.google.com/group/ruby_ire land/web/rails-resources http://railscasts.com/ http://www.railsenvy.com/ http://tinyurl.com/ytgp8d ;)http://tinyurl.com/ytgp8d

11. What we’ll cover :symbols Passing blocks Creating objects Closures

12. :symbols

13. “a”.intern = :a Symbols are ‘weird string’s Immutable (cannot be reassigned) Used internally to represent language elements eg: 100 would have a symbol assocaited with it Commonly used in hash maps as keys

14. Passing blocks (goal posts)

15. 3.times do puts “Hello world” End http://innig.net/software/ruby/closures-in-ruby.rb myArray = Array.new [3, 4, 3, 9] myArray.each do |i| puts I end Sans goalpoasts Avec goalpoasts

16. 3.times { puts “Hello world” } http://innig.net/software/ruby/closures-in-ruby.rb myArray = Array.new [3, 4, 3, 9] myArray.each { |i| puts i } Sans goalpoasts Avec goalpoasts

17. Hashes myHash = { :name => “James”, :occupation => “Programmer” } myHash.each { |i, k| puts “#{i}:#{k}” }

18. Everything is an object

19. class James initialize puts “initializing” @x = 3 # defines a member variable end # provides an accessor def x @x end # set x from outisde of the def x= arg @x = arg end http://innig.net/software/ruby/closures-in-ruby.rb

20. class Person attr_accessor :second_name initialize puts “initializing” @first_name = 3 # defines member variable end http://innig.net/software/ruby/closures-in-ruby.rb

21. ~ jkennedy$ irb irb(main):001:0> require 'test' => true irb(main):002:0> j = James.new initialising => # irb(main):003:0> j.x => 3 irb(main):004:0> j.x= 5 => 5 irb(main):005:0> j.x => 5 irb(main):006:0>

22. Exceptions

23. class RaisingExceptionionator def initialize begin file = open “some_file” rescue file = STDIN retry # error? end

24. Closures

25. # Example 1: def thrice yield end x = 5 puts "value of x before: #{x}" thrice { x += 1 } puts "value of x after: #{x}" http://innig.net/software/ruby/closures-in-ruby.rb

26. # Example 2: local scope def thrice_with_local_x x = 100 yield puts "value of x at end of thrice_with_local_x: #{x}" end x = 5 thrice_with_local_x { x += 1 } puts "value of outer x after: #{x}" http://innig.net/software/ruby/closures-in-ruby.rb

27. # Example 3: thrice do # note that {...} and do...end are equivalent y = 10 puts "Is y defined inside the block where it is first set?" puts "Yes." if defined? y end puts "Is y defined in the outer context after being set in the block?" puts "No!" unless defined? y http://innig.net/software/ruby/closures-in-ruby.rb

28. #Example 4: yield and scope def six_times(&block) thrice(&block) end x = 4 six_times { x += 10 } puts "value of x after: #{x}" http://innig.net/software/ruby/closures-in-ruby.rb

29. # Example 5 # So do we have closures? Not quite! We can't hold on #to a &block and call it later at an arbitrary # time; it doesn't work. This, for example, will not #compile: # # def save_block_for_later(&block) # saved = █ # end # # But we *can* pass it around if we use drop the &, and use block.call(...) instead of yield: def save_for_later(&b) @saved = b # Note: no ampersand! This turns a block into a closure of sorts. end http://innig.net/software/ruby/closures-in-ruby.rb

30. # Example 5 : … continued save_for_later { puts "Hello!" } puts "Deferred execution of a block:" @saved.call http://innig.net/software/ruby/closures-in-ruby.rb

31. @saved_proc_new = Proc.new { puts "I'm declared with Proc.new." } @saved_proc = proc { puts "I'm declared with proc." } @saved_lambda = lambda { puts "I'm declared with lambda." } def some_method puts "I'm declared as a method." end @method_as_closure = method(:some_method) puts "Here are four superficially identical forms of deferred execution:" @saved_proc_new.call @saved_proc.call @saved_lambda.call @method_as_closure.call http://innig.net/software/ruby/closures-in-ruby.rb

32. Modules Modules cannot be instantiated Define a set of ‘behaviours’ which an object can ‘inherit’ Module Politeness def say_hello puts “Hello” end

33. class Ambassador def initialize require ‘Politeness’ end kofi = Ambassador.new kofi.say_hello

34. Rails 2.0.2 : rails myfirstproject : cd myfirstproject : rake rails:freeze:gems : script/generate - -help : script/destroy - -help : script/migration - -help : script/resource - -help : script/scaffold - -help

35. Rails 2.0.2 : rails myfirstproject : cd myfirstproject : rake rails:freeze:gems : script/generate - -help : script/destroy - -help : script/migration - -help : script/resource - -help : script/scaffold - -help Freezing rails Imports the rails Code into your app

37. Sqllite :script/generate model Person name:string phone:integer biography:text :rake db:create :rake db:migrate :sqllite3 db/development.sqllite3 sqllite>.tables

38. Anatomy of a project Global configuration Methods available in views Active Record Classes * Templates Active Record Classes * URL => controller configuration

39. CRUD Create => [ new, update] Read => [ list, show] Update => [edit, update] Delete => [destroy]

40. Create rake rails:freeze:gems def new @item = Item.new end def update @item = Item.new params[:item] if @item.save flash[:notice] = ‘Item was created’ else render :action => “new” end

41. Read rake rails:freeze:gems def index @items = Item.find :all end def show @item = Item.find params[:id] end

42. Update rake rails:freeze:gems def edit @item = Item.find params[:id] end def show @item = Item.find params[:id] end

43. Delete rake rails:freeze:gems def edit @item = Item.find params[:id] @item.destory end

44. Adding Authentication./script/plugin install http://svn.techno- weenie.net/projects/plugins/restful_authenti cation/./script/generate authenticated user sessions Active Record Session only

45. Setting site template #{APP_ROOT}/app/views/layout/#{mod el_name}.erb renders content

46. Get a template Google: ‘yui builder’