comments (10)

  • This style of reactive programming is quite popular in JavaScript UI frameworks these days under the moniker “signals”, with a proposal for standardization here: https://github.com/tc39/proposal-signals#-javascript-signals...

    It’s used by frameworks Vue, SolidJS, Svelte, Ember, Angular, and there’s a few different implementations for React like Mobx and Jotai. There’s a few different algorithms for how to propagate changes and evaluate the DAG, I believe SolidJS2 uses a height-based algorithm similar to Incremental.

    I’ve been fooling around with an implementation that uses an Int32Array arena to allocate nodes and link them together with linked lists without paying O(dependency edges) GC load: https://github.com/justjake/dalien-signals/tree/dalien-signa...

    There are a few of these for Rust as well, Leptos is an example in UI frameworks, and Salsa is an example in general incremental computing, used in rust-analyzer.

    Another way to look at this sort of thing is as a build system with automatically tracked dependencies. One such build system is tup, which instruments build jobs to detect what files they read to establish dependency relationships. Interesting reading from the author: https://gittup.org/tup/build_system_rules_and_algorithms.pdf, see also the classic Build Systems à la Carte https://www.microsoft.com/en-us/research/wp-content/uploads/...

    jitl

  • One of my favorite tech talks is "Seven implementations of incremental": https://www.janestreet.com/tech-talks/seven-implementations-...

    lilactown

  • Goldman took the same approach with instrument pricing ~30 years ago. I recall long discussions about "Node Purpling" in my ~13 year tenure there.

    Computer Science has evolved, and AFAICT this is not a graph approach, but things like differentiation are computationally expensive, and therefore you want to minimize the number of times you do it to as close to the theoretical minimum.

    Edit: Related HN discussion https://news.ycombinator.com/item?id=36006737

    fadesibert

  • This is cool.

    As far as I can tell, incremental the library aims to solve the problem of partially hydrating a computation graph when source data is altered. This approach is similar to the one pursued by (well designed) build systems and is common in the FP world. [2] This has many use cases and is very cool.

    In addition, in the sphere of incremental computation, there exists Differential Dataflow, Timely Dataflow (adjacent), and DBSP. Systems like Feldera are built on DBSP. Materialize is lead by some DD guys.

    Personally, I am pursuing an orthogonal approach specifically for the problem of financial data and financial workloads, There exists huge, very important problems to solve! [1]

    [1] https://modolap.com

    [2] Signals And Threads episode on the subject https://signalsandthreads.com/build-systems/

    ronfriedhaber

  • I was very curious about Dataflow programming years ago - I think a lot of people were coming at this problem from various angles. This specific library immediately reminded me of Javelin from Clojure [0]

    [0]: https://github.com/hoplon/javelin

    djtango

  • If you find this interesting, also check out their UI library called Bonsai that built on top of Incremental: https://github.com/janestreet/bonsai/

    Libraries like React are pretty efficient with skipping work by using Virtual Dom, but constructing this vdom still takes time. Bonsai makes the vdom incremental and it is pretty fun to work with.

    I built a desktop UI library with it by targeting (now unmaintained) Revery. It is using a much older version of Bonsai however: https://github.com/ozanvos/bonsai_revery

    osener

  • One thing I've never fully grokked is how this differs from an observable pattern where one can publish new values to inputs, propagate that through the computation, and push newly computed values to listeners.

    I guess there's probably optimizations around change detection and stopping the propagation if there's no change (though observables can do that as well). The stabilize command also makes things interesting as a way to batch changes together before recomputing (but again, doable with observables too).

    Is the delta primarily coming from introspection and automatically building the compute graph? Or is there something more fundamental that I'm missing?

    RandomBK

  • One thing i have always linked about Jane street projects is that they tend to package ideas that have existed in research or niche system into something developers can actually use. Even if you never adopt the library, the design docs are usually worth reading.

    runtime_lens

  • Electric Clojure does incremental rendering that crosses the client/server boundary: http://electric.hyperfiddle.net/

    The closest thing to Electric (IMO) is SolidJS, but frontend only: https://www.solidjs.com/

    pgt

  • I don't understand how to use this library, as it doesn't seem to indicate what language it is for, but the concept sounds very cool.

    Magicrafter13