fx

Version: 0.9.73 · 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 # v0.9.73
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. Pins: fx new writes fx.mod. Optional fx mod vendor / verify checksum std; compile still uses the std/ beside your project (or 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 Weekend path	docs/WEEKEND.md — hello → CLI → fxserve
3 Backends	docs/DRIVERS.md — Auto / emit-C / IR / --driver sh
4 Language	docs/LANGUAGE.md
5 Composition	docs/COMPOSITION.md
6 Regions / caps	docs/REGIONS.md
7 Wrap / C host	docs/WRAP.md
8 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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Companion tools (separate packs)

Install from GitHub Releases (Win + Linux x86_64). Requires fx 0.9.6+ (prefer 0.9.73+). GPL-3.0.

Tool	Role	Repo
fxrun	Task runner (fxrun.toml)	ledocorp/fxrun
fxql	SQLite one-shot + FsCap	ledocorp/fxql
fxlz4	LZ4 pack/unpack	ledocorp/fxlz4
fxblake3	BLAKE3 file/tree hash	ledocorp/fxblake3
fxfetch	HTTPS GET + NetCap	ledocorp/fxfetch
fxpipe	Parallel BLAKE3 + nursery	ledocorp/fxpipe
fxguest	Cap speech (allow/deny/fuel)	ledocorp/fxguest
fxserve	Local static HTTP(S)	ledocorp/fxserve

Site index: https://www.ledocorp.org/fx/tools/ · Detail: docs/LIBRARIES.md.

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What’s in 0.9.73

• Stable baseline for building real tools (platforms, argv, package pins locked; not labeled v1.0)
• Weekend path — docs/WEEKEND.md · compile map — docs/DRIVERS.md
• fx new writes fx.mod — optional fx mod vendor / verify for checksums
• Thin teaching examples — language-focused demos only
• Web scaffold — fx new mysite web
• Companion tools — fxserve and other CLIs in separate GitHub releases
• Carry-forward: GPL-3.0, default Auto fx run, --emit-c, IR when QBE is present

Full notes: docs/releases/0.9.73.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: 0.9.73.