dustingetz

Missionary concept map

Missionary primitives fit into three categories:

Effect descriptions = pure functional programming which is about trees not graphs

• continuous flow, m/?< (switch)
• m/watch, m/latest, m/cp
• m/observe
• m/reductions, m/relieve

dustingetz

PostgreSQL hello world — Electric Clojure

How do I integrate a SQL database backend?

Easy:

• make an ordinary Clojure function query-pokemon-list for the query
• The query is blocking, and Electric Clojure is async, so use e/offload to move it to a thread pool.
  • (Don't block the event loop!)
• e/offload throws Pending until the query finishes, and then the exception "goes away"

dustingetz

Multiplayer chat with presence – Electric Clojure

• 60 LOC: demo_chat_exdended.cljc

20230131.presence.edited.mp4

dustingetz

TodoMVC Composed (it's just a for loop!!!) — Electric Clojure

• An early demonstration "Compiler Managed Network" and the extreme dynamic composition it makes possible
• TodoMVC Composed merely calls the previous TodoMVC function inside a for loop.

20220822.Todomvc.Composed.mp4

dustingetz

TodoMVC, with a twist! — Electric Clojure

1. it's multiplayer! 0 LOC cost
2. state is durable! (server side database) 0 LOC cost
3. See those pending spinners? We've added a server delay to demonstrate managed load states.

20220817.todomvc.mp4

Electric is a "multi tier" Clojure/Script dialect for full-stack web application development. It uses macros to let you interweave client and server code in a single .CLJC file, so you can define a full-stack frontend/backend webapp all in one place. Electric is designed for rich dynamic applications with reactive user interfaces and complex frontend/backend data sync requirements.

dustingetz

References — Electric Clojure

Electric Clojure implements a form of arrowized continuous time dataflow programming with extensions for network-transparent function composition.

• The Haskell School of Music: From Signals to Symphonies (2018) — best starting point and also a great intro to Haskell.
• The Essence of Dataflow Programming (2006) great category theory overview of dataflow programming; missing Applicative (2008), Free monad and Cofree comonad
• Push-pull functional reactive programming, Elliot (2009)
• Breaking down FRP, Jane Street (2014) — good concise comparision of many FRP aspects; missing discussion of discrete vs continuous
• [Compiling to Categories, Elliott (2017)](http

dustingetz

(ns contrib.ui.remark
  (:require
    ;["@hyperfiddle/remark-generic-extensions/lib/browser.min" :as remark-generic-extensions] ; works in node
    [clojure.set]
    [clojure.string]
    ; Refrain from contrib imports so this is more suitable for userland
    [goog.object]
    [prop-types]                                            ; used as js/propTypes.object
    [reagent.core]
    ;[remark] ; works in node

dustingetz

React.js interop POC — Electric Clojure

• 80 LOC: demo-reagent-interop.cljc (25 LOC for adapter)

20220729.photon.reagent.react.interop.mp4

dustingetz

Direct recursion over file system from the frontend — Electric Clojure (2022 June)

This video demonstrates traversing a filesystem tree from the frontend. The filesystem tree exists only on the server, and the HTML view exists only on the client. Nonetheless, we are able to unify the query/view logic into a single recursion in the simple, direct style of PHP, despite network. The Electric compiler automatically coordinates fine-grained reactive network sync.

Code note: in this video from last year, ~@ is the legacy syntax for client/server transfer, it has since been superseded by e/client and e/server markers.

20220621.photon.treeview.with.managed.nework.mp4

• No API, no client side database, no frontend state at all (except DOM)
• Literally all accidental complexity GONE

dustingetz

Datomic web explorer

• Client API, tested on Datomic Cloud
• database entity browser
• server paginated infinite scroll
• streaming information model - displays incremental resultsets as they become available (useful for slow queries)
• automatic backpressure and cancellation of abandoned queries
• custom web renderers with dynamic queries

Code is not optimized yet – we are still learning the idioms.