HAML – HTML Abstraction Markup Language is best described as a layer on top of XHTML that lays down the structure of documents written within XHTML specification, facilitating the embedding of Ruby (and it’s frameworks like Merb, GRails or Ruby on Rails).

Haml was originally developed for Ruby on Rails, but further development of this RoR plugin made it independent of Rails – it can now function nas a standalone templating engine.

Before you put Haml 3.07 in you Ruby on Rails application make sure you acknowledged the backward incompatibilities of Haml 3.x.x versions and older versions of Ruby on Rails framework (all versions before 3.x).