June 2022 by Dustin Getz

see r/clojure discussion here

This is a collection of twitter-length video demos filmed in Q2, demonstrating Photon. By abstracting over the client/server boundary with a language and building network into the language runtime, Photon lets you build full-stack web UIs where the view can query the backend directly, in the straightforward/easy style of PHP.

First demo of Photon client/server transfer

This function App is a “full stack” function that crosses network to do both frontend things and backend things in the same function:

20220623 button counter with transfer.mp4

• p/defn defines a function that follows all the same laws as regular Clojure functions, but it’s actually a macro that compiles the function body into a DAG (Directed Acyclic Graph).
• The DAG forms an event propagation network, resulting in reactive rendering like React.js. (No React.js on the page; fine-grained direct DOM effects are scheduled by https://github.com/leonoel/missionary, a functional effect and streaming system for Clojure/Script)
• The sigil ~@ marks streaming client/server transfer points in the DAG. It’s currently a relative toggle. (This syntax was an error – we are replacing it with something much better soon!)
• If the frontend backend is reactive, and the backend is reactive, inserting a small delay for a websocket hop has no impedance with the already async computation model. And your database queries are already heavier than a websocket hop.
• Today’s photon-dom syntax is low-level, because we are still working out the idioms. High level syntax and abstract controls for application developers are coming!
• For a deeper explanation, see Talk: UIs are streaming DAGs (Getz 2022)

Two Clocks, the first compiler-managed network stress test