gistfile1.rb

# @reference http://ruby-metaprogramming.rubylearning.com/html/Dog_Step2.html

class Dog
  PHRASES = {
    :dance => 'is dancing',
    :poo => 'is a smelly doggy!',
    :laugh => 'finds this hilarious!'
  }

  def initialize name
    @name = name
  end

  def name
    @name
  end

  def can *actions, &blk
    @actions ||= {}

    actions.each do |action|
      @actions[action] = PHRASES[action] if PHRASES.include? action
      @actions[action] = instance_eval &blk if block_given?
    end
  end

  def method_missing missing_method, *args
    action = missing_method

    if @actions.include?(action) || PHRASES.include?(action)
      verb = @actions.include?(action) ? @actions[action] : "doesn't understand #{action}"
      verb.start_with?(@name) ? verb : "#{@name} #{verb}"
    else
      super
    end
  end
end

lassie, fido, stimpy = %w[ Lassie Fido Stimpy ].collect { |name| Dog.new name }
lassie.can :dance, :poo, :laugh
fido.can(:poo) { "#{name} is smelly." }
stimpy.can :dance
stimpy.can(:cry) { "#{name} cried AHHHH" }

p lassie.dance
p lassie.poo
p lassie.laugh
puts
p fido.dance
p fido.poo
p fido.laugh
puts
p stimpy.dance
p stimpy.poo
p stimpy.laugh
p stimpy.cry