This is how I'd like to write markup in say index.html.erb

<%= page_for "Super Cool Page" do |p| %>
    <%= p.header do %>
        Ruby is Cool
    <% end %>
    <%= p.body do %>
        Witty discourse on Ruby.
    <% end %>
    <% if page.has_sidebar? %>
        <%= p.sidebar do %>
            <ul><li>Option 1</li></ul>
        <% end %>
    <% end %>
<% end %>

Which would output

<div class="page">
    <header><h1>Super Cool Page</h1></header>
    <section>
    Witty discourse on Ruby.
    </section>
</div>

and when page.has_sidebar? is true

<div class="page">
    <header><h1>Super Cool Page</h1></header>
    <asside><ul><li>Option 1</li></ul></asside>
    <section>
    Witty discourse on Ruby.
    </section>
</div>

I've taken a look at the FormHelper class in rails for guidance, but it seems like I'd have to duplicate a lot of work which I'm trying to avoid. I'm really just trying to figure out where to hang the classes/modules/methods in the framework and whit kind of object |p| should be.

My first inclination was to create a PageBuilder class that implements header, body and sidebar methods. But I got stuck on the rendering pipeline to get everything output just right.

Is there a gem that already provides this type of semantic generation? If not I'd love any insight on how to set this up.