What technology is behind Visual Workflows/ Process Builder?
See salesforce.com/video/303091, fwd to 38:28... per Josh Kaplan, none of the declarative tools compile into java bytecode instructions. They all have separate engines, non-Apex. Specifically Josh mentioned that 1) Flow, 2) "Process" (by which I assume he means Process Builder), and 3) rendering VisualForce for Lightning each have their own distinct engine.
So, what technologies are being used here?