Clojurians Log v2

> does each computational unit (process/fiber?) in Missionary carry the full state and allow each viewer to deref it, or get a delta? Yes. The computational unit is the signal, which is essentially a memoized view of an effect producing a sequence of diffs over time. The process itself is not exposed, its lifecycle is managed (spawned on first sub, killed on last unsub). Subscriptions can occur at any point in time and each subscriber can consume diffs at different rates. Therefore, a reducing function must be provided as argument to m/signal (the diff semigroup) such that successive values can be collapsed (like a squashed commit in git). Each signal keeps track of its full history as a single aggregated diff. A good semigroup function should be able to keep the aggregated diff bounded in memory over an indefinite time (e.g. for sequence diffs, additions and removals cancel each other).

So is the expectation that a remote reader may perform a "read" on the signal every so often and that would reset the diff? From what it sounds like: • push driven parts of the app can push at will and their results will be aggregated into the diff via the reduce function • pull driven parts can get the current value at any time, which would reset the diff. Let's say I wrote a system on this where these signals contain 10k items. With a "snapshot is available at any time" approach it seems like I'd need to have those 10k items in memory all at once. Diffs help, but if a subscriber can arrive at any time, the new subscriber would need a snapshot, hence needing that snapshot in memory at all times.

the dual-driven approach of missionary is interesting though, as is the ability for each consumer to handle updates however they wish

that's correct, your dataset must indeed fit in memory

just to be clear, we see a UI as a bounded tree of small collections which is then incrementally written to e.g. the DOM. i.e., all collections are bounded, a fullscreen grid has maybe 100 visible rows

unfortunatelyTim, we are a business, you are not our customer

I haven’t read it myself so I can’t say for sure it would be helpful, but at least it’s long 🤷 https://nextjournal.com/N-litened/missionary-for-dummies

That wasn't intended as a insult @dustingetz, I'm trying to understand the tech in the context of existing work. I'm painfully aware of the issues with Rx, done research into Timely Dataflow, Niad, and the like. At a baseline I'm trying to figure out in what areas hyperfilddle innovates and in which it copies. Based on that I can figure out if I need to dig more into the tech. Every project has its tradeoffs, and I'm trying to find the paradigm that matches closest to the tradeoffs I need to make in my project. The project I'm writing isn't even in clojure, so one of the first things I'm trying to decypher is how much of the magic of hyperfiddle is tied to dom-diffing, the ability to construct a DSL in Clojure, dynamic programming, or any number of other features that I don't have access to. But, I don't want to be a bother, so I'll go poke around in the code more. Thanks for taking the time to answer my questsons thus far.

We are very happy to answer questions, the problem with this particular message at the root of this thread is it does not contain one, rather it contains an expression of your emotions or something. For clarity, a question is a sentence starting with a question word such as "what why how" and ends in a question mark. "Where do the diffs come into play" is an excellent question and therefore it received an answer!

fair enough, let me reframe my questions

excellent, thank you and looking forward!