anchor.diff:  <% end -%>
   <% end # frontend loop -%>
   <% end # frontend -%>
  -
   <% unless @backend.nil? %>
  +
   <% @backend.each do | key, backend | %>
   
   backend <%= key %>
  
positive.code:   use_backend <%= backend %>
  <% end -%>
  <% end -%>
  
  <% unless listen['extra_options'].nil? %>
  <% listen['extra_options'].each do | key, value |%>
  <% if value.is_a?(Array) %>
  
negative.code: <% end -%>
  <% end -%>
  <% end -%>
  <% unless @frontend.nil? %>
  
  <% @frontend.each do |frontend, f | %>
  
  frontend <%= frontend %>
  