Ruby Language Demo Demo (5 Minutes)

Description

Product Versions Supported

Points to Hit

• Code completion and integrated RDoc
• Pair matching
• Live code templates
• IRB Integration

Demo Prep

Gotchas

Demo

Ruby Editor

1. Create a new Ruby Application named Blog in the root of your user directory (it will be quicker to find using IRB)
2. In main.rb, add the following:
3. Type cl and press Ctrl+Space to show the code completion and RDoc. Show how you can navigate to the Ruby source. Select class and then complete the rest of the class:

     
  class Blog
    attr_accessor :title
       
    def initialize( title )
      @title = title
    end        
  end

1. Point out the Rubyisms:
   1. end instead of closing brace (and it was pair matched for us)
   2. attr_accessor instead of getters and setters
   3. def for method definitions
   4. @ marks an instance variable

1. Save the file.

IRB

1. Start the IRB (from the top of the Window > Other menu)
2. b = Blog.new( 'Ruby Blog' ) (fails)
3. load 'main.rb' (fails)
4. Dir.pwd (note you can use tab completion here)
5. Dir.chdir( "Blog//lib" ) on Windows or ( "Blog/lib" ) on UNIX
6. load 'main.rb'
7. b = Blog.new( 'Ruby Blog' )
8. b.title

Method Missing & Metaprogramming

1. Add the following method to main.rb (hint: put the code in a template):

  def method_missing( method )
    puts "There was no #{method} method, but please try again."

    Blog.class_eval do
      define_method  method do
        puts "Hello from the #{method} method."
      end
    end
  end

1. In IRB, load main.rb
2. b.post - returns "There was no post method..."
3. b.post - returns "Hello from the post method."
4. Another way to add methods (do the following in IRB)

  class Blog
    def add_comment
      puts "Comment added"
    end
  end

1. b.add_comment

Demo Cleanup

• Delete the Blog application