Spectrum (WIP)

A syntax highlighter written in php. This project is inspired from prism.js by @LeaVerou.

Requirements

All the processing done server side. Save browser redraws and repaints that may be caused due to javascript alternatives.
Makes highlighted code cacheable, which is not possible otherwise.
Encourages semantic approach of using language-xxx class on code blocks specified by W3C.
Very easy to define new languages. Only thing you need is a good understanding of regular expressions.
All styling is done through CSS, with sensible class names.
Wide browser support. Even the ancient IE6-8. If your browser supports pre and code tags and CSS, you are good to go.
Highlights nested languages (CSS in HTML, JavaScript in HTML).