Presenter

haml_presenter.rb

class HamlPresenter < Presenter
  include Haml::Helpers
  
  def initialize(locals = {})
    super
    init_haml_helpers
  end
end

presenter.rb

class Presenter
  attr_accessor :object, :template

  def initialize(object, template)
    @object = object
    @template = template
  end

  def self.presents(name)
    define_method name do
      @object
    end
  end
 
  def inspect
    "#<#{self.class.name} #{locals.map { |key, value| "#{key}: #{value}" }}>"
  end
 
  def method_missing(method_name, *args, &block)
    if template and template.respond_to?(method_name)
      template.send(method_name, *args, &block)
    else
      super
    end
  end
 
  def respond_to_missing?(method_name, include_private = false)
    (template and template.respond_to?(method_name)) or super
  end
end

presenter_helper.rb

module PresenterHelper
  def present(object, klass = nil)
    klass ||= "#{object.class}Presenter".constantize
    presenter = klass.new(object, self)
    if block_given?
      yield presenter
      presenter
    else
      presenter.render
    end
  end
end