hopsoft

module MagicShow

  def show
    method_name = params[:id]
    if respond_to? method_name
      send(method_name)
    else
      render :text => "That operation is not supported!", :layout => false
    end
  end

hopsoft

# setup a contrived class to demonstrate pattern dispatch
class Person
  attr_accessor :first_name
  attr_accessor :last_name
  attr_accessor :pets_name
  attr_accessor :mothers_maiden_name

  def drag_queen_name
    "#{pets_name} #{mothers_maiden_name}"
  end

hopsoft

# define our example class
class Example
  # catch all calls to methods that don't exist
  def method_missing(method_name, *args)
    puts "You called '#{method_name}' with these arguments: #{args.inspect}"
  end
end

# invoke methods that haven't been defined
Example.new.some_method # => You called 'some_method' with these arguments: []

hopsoft

class Proxy
  def initialize(object)
    @object = object
  end

  # forward all calls to the wrapped object
  def method_missing(method_name, *args)
    @object.send(method_name, *args)
  rescue 
    puts "#{method_name} is not supported by the wrapped object!"  

hopsoft

# setup some data that will drive what methods get defined
$method_names = [:hello, :goodbye]

# define our example class
class Example
  # define some dynamic methods
  $method_names.each do |method_name|
    define_method(method_name) do |name|
      puts "#{method_name} #{name}!"
    end

hopsoft

# demonstrate how to remove functionality
String.class_eval do
  undef_method :length
end
"test".length # => NoMethodError: undefined method `length' for "test":String

# create a blank slate class
class BlankSlate
  public_instance_methods.each do |method_name|
    undef_method(method_name) unless method_name =~ /^__|^(public_methods|method_missing|respond_to\?)$/

hopsoft

def async_example(arg, delay=1.0)
  Dispatch::Queue.new('org.macruby.examples.gcd').async do
    start = Time.now
    sleep delay
    puts "finished async_work for: #{arg} in #{(Time.now - start).round} secs"
  end
end

async_example(:first, 5.0)
async_example(:second, 4.0)

hopsoft

# demonstrate scoping in ruby 
scope = "global scope"
puts(scope) # => global scope

class ExampleClass
  # the globally scoped variable isn't defined in the classes' scope
  defined?(scope) # => nil
  scope = "class scope"
  puts(scope) # => class scope
end

hopsoft

# app/models/user.rb
class User < ActiveRecord::Base
end

# lib/user_logger.rb
module UserLogger
  def self.included(mod)
    mod.send :after_create, :log_creation
  end

hopsoft

# An attempt to define a standard interface for monkey patching existing method definitions
# on existing Object instances, Classes, and Modules.
#
# This effort warrants a new monkey patching nomenclature.
#   * Monkey Patch - a re-definition of an existing method that was patched via MonkeyPatcher
#   * Patch - a re-definition of an existing method
#
# Lets get started with some usage examples.
# First lets add some helper methods to all objects.
#