Comment by haxiomic

Funny enough this project is a descendent of the flash lineage – it's written in haxe which first existed as an alternative ActionScript compiler. It's since evolved to be a strong functionally focused language of its own and perfect for writing games and interactives like this and now exports js instead. There's even a project (OpenFL) to preserve the old APIs!.

A good example of how haxe has evolved since AS2, the author (saharan) has written their own shader language _in_ haxe which they've used in this project. Haxe has a compile-time macro engine which you can develop DSLs to improve your workflow https://github.com/saharan/HGSL