I re-implemented (most of) TPLang (mentioned above) in pure JS , and called it openjscam [1] And am working on open source software for CAM (as a hobby), just 2.5D gcode generators, using maker.js and openjscam [2]. And made opencamlib compile on Mac and Windows (and added basic Node.JS bindings) [3]

I am hoping more people will work on open source g-code generators so we have better alternatives to Fusion 360 / Solidworks for free

[1] http://github.com/makercam/openjscam [2] http://github.com/makercam [3] https://github.com/aewallin/opencamlib