Dynamic Method - Illustrates how to define methods dynamically at runtime

dynamic_method.rb

# 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
  end
end

# test out our dynamic methods
Example.new.respond_to? :hello # => true
Example.new.respond_to? :goodbye # => true
Example.new.hello("nathan") # => hello nathan!
Example.new.goodbye("nathan") # => hello nathan!