Reactive.jl which Escher depends on for interaction was entirely inspired by Elm! I think the main difference between Elm is that Elm is currently a client-only compile-to-JS language. Escher, otoh runs on the server and compiles to Virtual DOM instead of JS. The Virtual DOM can include custom HTML elements, I use Polymer extensively, and have a few elements of my own for doing things like event capture, websocket communication, sampling events etc.