“Haml is a markup language that‘s used to cleanly and simply describe the XHTML of any web document, without the use of inline code. Haml functions as a replacement for inline page templating systems such as PHP, ERB, and ASP. However, Haml avoids the need for explicitly coding XHTML into the template, because it is actually an abstract description of the XHTML, with some code to generate dynamic content.”

Basically Haml is a domain specific language for XHTML. Unlike Velocity, which can be used to output any text data, Haml focuses entirely on xhtml output — and does it well.

Instead of:

  
<h2><%= ViewData.CategoryName %></h2>
<ul>
    <% foreach (var product in ViewData.Products) { %>
      <li>
        <%= product.ProductName %>
        <div class="editlink">
          (<%= Html.ActionLink("Edit", new { Action="Edit", ID=product.ProductID })%>>
        </div>
      
    <% } %>
  </li></ul>
  <%= Html.ActionLink("Add New Product", new { Action="New" }) %>

You can do this:

%h2= ViewData.CategoryName
%ul
  - foreach (var product in ViewData.Products)
    %li
      = product.ProductName 
      .editlink
        = Html.ActionLink("Edit", new { Action="Edit", ID=product.ProductID })
        = Html.ActionLink("Add New Product", new { Action="New" })

(It does look like python, doesn't it?)

Do we need it?

Andrew Peters has created a NHaml, .NET port of Haml made as an alternative view engine for ASP.NET MVC.

I assume it wouldn't be too hard to take it apart and create a Haml rendering type for Sitecore as a downloadable extension. Is this something you find interesting? I love its clarity and wrist-friendliness, and it should be much easier to type online using Developer Center or even Content Editor.

The downside is that you'd lose intellisense in visual studio, but personally I'm much more annoyed by visual studio trying to format my <% %> code the way it thinks i like it. And yes, it's yet another templating engine.

* Haml reference