Wrapping a collection of objects in a Presenter more transparently. Expanding on ideas distributed by Jim Gay (http://clean-ruby.com/).

after.erb

<ul>
<% agenda.sessions.each do |session| %>
  <li>
    <h3><%= session.title %></h3>
    <p><%= session.other_view_method %></p>
  </li>
<% end %>
</ul>

after.rb

class ResultsPresenter < ::Presenter
  def sessions
    Enumerator.new do |yielder|
      presenter = AgendaBuilder::SessionPresenter.new(nil, view)
      results.sessions.each do |session|
        presenter.session = session
        yielder << presenter
      end
    end
  end
end
  

before.erb

<ul>
<% agenda.each_session do |session| %>
  <li>
    <h3><%= session.title %></h3>
    <p><%= session.other_view_method %></p>
  </li>
<% end %>
</ul>

before.rb

class ResultsPresenter < ::Presenter
  def each_session(&block)
    presenter = AgendaBuilder::SessionPresenter.new(nil, view)
    sessions.each do |session|
      presenter.session = session
      block.call(presenter)
    end
  end
end