Diazo (formerly known as XDV) approach to Plone theming is an attempt to implement the Deliverance concept using pure XSLT. This is a way to apply a style/theme contained in a static HTML web page (with related CSS, JavaScript and image resources) to a dynamic website created using any server-side technology. This approach is widely used outside Plone, that is why the name ‘Diazo’ was unveiled for collective.xdv to help separate it from other related technologies and to define the Plone-specific story for theming with the xdv approach.
Such approach is particularly suitable when implementing a theme into a dynamic website by a web designer, who is not familiar with the technology behind the dynamic website. Web designer provides a static version of the site, that consists of an HTML file with more-or-less semantic markup, one or more style sheets, and some other resources like images or JavaScript files.
Using XDV a theme can be applied to a dynamic website by identifying such things as placeholders for replacing theme file elements with dynamic elements, markup in the dynamic website, and parts of the theme and/or dynamic website that are superfluous. For every of the above mentioned cases, XML rules are to be set. As soon as there are theme HTML file and a rules XML file, they can be compiled into a single XSLT file.
The Diazo (XDV) theming engine enables themes to be created without reference to the various markup generating technologies which make up a Plone page.
See Diazo/collective.xdv getting-started guide at: http://pypi.python.org/pypi/collective.xdv