A BSD licensed javascript implementation of some of the mapnik Layer, Rule, Style and symbolizer
classes (implemented mainly by eye-balling the XML and reading the wiki).

Also javascript classes to take XML from the OpenStreetMap API and turn it into GeoJSON-ish things.

Also javascript classes to make using Array.filter more sane, and slightly SQL-ish.

Nowhere near feature complete. There is an initial attempt to implement text rendering, 
which is where things should get interesting.

OpenLayers has a similar set of classes for styling vector data, and Cartagen also explores
similar ideas.

TODO:
 - proper projections (right now things just get squeezed into squares)
 - more symbolizers (text, point, etc)
 - try an SVG renderer instead of canvas (DOM is handy!)
 - load and parse mapnik-ish xml files (URLs for sources?)
 - load and parse cascadenik files (CSS++)
 - use something like YQL to transform the XML to GeoJSON on a server?