Beautiful template logic

Papercraft

->(show_books, books) {
  if show_books
    ul {
      books.each {
        li {
          a it.title,
            href: it.href
        }
      }
    }
  end
}

ERB/Erubi


<% if @show_books %>
<ul>
  <% @books.each do %>
    <li>
      <a href="<%= it.href %>">
        <%= it.title %>
      </a>
    </li>
  <% end %>
</ul>
<% end %>