Victor Borja vic

Composable Effectful Computations in Rust: Integrating Algebraic Effects, Lenses, and Contextual Adaptation

fx-rs: An algebraic effects system for Rust.

Abstract

Effect systems have become a powerful tool for structuring modular, composable, and type-safe effectful computations. While algebraic effects and handlers have seen widespread adoption in languages like Haskell and OCaml, their integration in Rust remains limited. We present Fx, a novel effect system for Rust that unifies algebraic effects, lenses, and contextual adaptation in a single, extensible abstraction. Fx enables ergonomic composition of effectful computations, modular interpretation via handlers, and fine-grained state manipulation using lenses. We demonstrate how Fx supports advanced patterns such as context adaptation and effectful accumulation, and evaluate its expressiveness and ergonomics through practical examples. Our work shows that Rust’s type system and ownership model can support advance

Keybase proof

I hereby claim:

I am vic on github.
I am oeiuwq (https://keybase.io/oeiuwq) on keybase.
I have a public key ASDl3QUhn_Iv58GAMXdWpgBTMfK7AB_NVO7Kfd37fv2zPgo

To claim this, I am signing this object:

Install d12frosted/emacs-plus on mac patched for rich colors on terminals supporting direct color (like iterm2).

brew install emacs-plus --with-24bit-color

Generate the terminfo (see attached .src file)

Then run emacs/emacsclient with TERM set to xterm-24bits

	{
	outputs = inputs: {
	overlays.foo = final: prev: {
	foo = final.writeShellScriptBin "foo" "echo FOO";
	};

	overlays.moo = final: prev: {
	moo = final.writeShellScriptBin "moo" "echo MOO";
	};
	};

	const std = @import("std");

	const Allocator = std.mem.Allocator;

	const ConstantInput = *const []const u8;

	const NumIdx = struct {
	fromIdx: usize,
	toIdx: usize,
	pub fn text(self: NumIdx, input: ConstantInput) []const u8 {

	before_install:
	- curl -o scala-cli https://raw.githubusercontent.com/VirtusLab/scala-cli/main/scala-cli.sh
	- chmod +x scala-cli
	install:
	- \|
	./scala-cli --power publish --publish-repository $HOME/.m2/repository --organization "$GROUP" --name "$ARTIFACT" --version "$VERSION" .
	ls -R $HOME/.m2/repository/
	find $HOME/.m2/repository -type f -name "*.pom" -exec cp -v {} $PWD \;

	import mill._

	trait BuildrModule extends Module {

	def logger = {
	val colors = interp.colors()
	new mill.util.PrintLogger(
	colors != ammonite.util.Colors.BlackWhite,
	false,
	colors.info(),


	import com.raquo.airstream.flatten.FlattenStrategy
	import com.raquo.laminar.api.L._
	import com.raquo.laminar.nodes.ReactiveElement
	import com.raquo.laminar.nodes.ReactiveHtmlElement

	import scala.util.Failure
	import scala.util.Success
	import scala.util.Try
	import org.scalajs.dom

	/**
	* Usage:
	*
	* ammonite SlothMux.sc runServer
	*
	* ammonite SlothMux.sc runClient
	*/

	import $ivy.`io.catbird::catbird-finagle:21.8.0`
	import $ivy.`com.twitter::finagle-mux:21.8.0`

	❯ ./mill scalajslib.test 'mill.scalajslib.HelloJSWorldTests.fastOpt'
	[94/356] scalajslib.worker[1].compile
	[info] Compiling 1 Scala source to /h/mill/out/scalajslib/worker/1/compile/dest/classes ...
	[warn] 1 deprecation (since 2.13.0); re-run with -deprecation for details
	[warn] one warning found
	[info] Done compiling.
	[221/356] main.core.compile
	[info] Compiling 1 Scala source to /h/mill/out/main/core/compile/dest/classes ...
	[info] Done compiling.
	[356/356] scalajslib.test.test