Quarto is a project mainly written in Ruby, it's free.
A Ruby framework for generating complex web sites from XML.
Quarto is a Ruby framework for generating collections of documents from XML. Potential applications include web sites and e-books. It's built on top of ERB and REXML. It works as a standalone application and inside Rails.
Quarto was built with HTML output in mind, but there's nothing to prevent you from outputting to any other format. You could even output to an interpolated scripting language like PHP.
As of the inception of Quarto, there is no cross-platform XSLT gem. So, Quarto comes with its own alternative to XSLT in the form of the Tranformer class and the TransformationHelper module.
Say you have a book in XML format, and you want to make a web site from it. You could transform it to HTML using XSLT. But what if you need logic that can't be implemented in XSLT?
Enter Quarto. Instead of writing a series of XSLT sheets, you write ERB templates. You implement whatever custom logic you need in classes that wrap the DOM elements, then you pass variables to the templates.
gem sources -a http://gems.github.com sudo gem install jarrett-quarto
Thorough documentation doesn't exist yet. For now, see spec/sample_project and the RDoc.