fx

Version: 0.9.72 · Release notes · GitHub

Copyright © 2026 Shawn Londono · LedoCorp · http://www.ledocorp.org License: GNU GPL v3 · NOTICE · third-party licenses

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What fx is

fx is a systems language with visible control.

Named regions + effects in signatures. Native-first fx run (the primary compiler path when the program fits; otherwise a built-in fallback engine inside bin/fx). IR → native on that fallback path when QBE is present. Emit-C stays first-class and readable. Wrap mature C libraries instead of rewriting them.

This repo is the language package: put bin/ on your PATH and write fx. License: GNU GPL v3 — see LICENSE.

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Install / try (2 minutes)

Needs: this repo · gcc (or clang/zig) · Windows or Linux x86_64 (no macOS prebuilt).

# put bin/ on PATH, then:
fx doctor
fx version # v0.9.72
fx new hello
cd hello
fx run main.fx # expect exit 42

OS	Binary	IR (when staged)
Windows	bin/fx.exe	third_party/qbe/windows/qbe.exe
Linux	bin/fx	third_party/qbe/obj/qbe

Without QBE, use fx run main.fx --emit-c. Layout: PACKAGE.md. Argv: fx run does not forward program args — use --scaffold cli / --host. Vendor: fx mod pins checksums; compile still uses std/ / FX_STD_ROOT.

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The idea in one screen

import std/vec;

fn main() -> i32 effects { alloc, mut } {
 region r = arena(4096);
 let v: Vec<i32> = vec.new(0);
 let v2: Vec<i32> = vec.push(v, 40);
 let v3: Vec<i32> = vec.push(v2, 2);
 return vec.get(v3, 0) + vec.get(v3, 1); // 42
}

fx run main.fx --emit-c
fx emit-c main.fx -o out_c
fx run lib.fx --host host.c

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Learn path (read in order)

Also on the web: https://www.ledocorp.org/fx/docs/

Step	Doc
1 Install	docs/START_HERE.md
2 Language	docs/LANGUAGE.md
3 Composition	docs/COMPOSITION.md
4 Regions / caps	docs/REGIONS.md
5 Wrap / C host	docs/WRAP.md
6 CLI	docs/CLI.md
Map	docs/SURFACE.md — as-implemented cheatsheet
Tracking	docs/TRACKING.md
Std / Reference	docs/STD.md · docs/REFERENCE.md

What’s next: docs/NEXT.md.

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What’s in 0.9.72

• Thin teaching examples (T0) — language-focused demos only; season/tool galleries not mirrored in this package
• Web scaffold — fx new mysite web
• Serve / net capabilities proven in monorepo / companion tools (fxserve) — not claimed as a demo zoo here
• Carry-forward from 0.9.71 — Atomic · MMIO · CapDict IR when QBE staged; facets; GPL-3.0; native-first Auto
• Teaching demos: examples/showcase_core/, examples/wasm_smoke/, examples/capdict_writer/, …

Full notes: docs/releases/0.9.72.md.

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Tooling

• fx doctor · fx lsp · fx mcp (check / locate / run)
• Editor day-one: docs/EDITOR.md

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Contributing & security

Maintained by Shawn Londono / LedoCorp. PRs not accepted; issues welcome for bugs. CONTRIBUTING.md · SECURITY.md

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Releases

Newest first under docs/releases/. Latest: 0.9.72.