moonbit-overlay

Versioned, binary-distributed MoonBit toolchains for Nix. Each package contains the matching compiler, CLI, language server, runtime tools, and bundled core library.

This repository handles toolchain distribution. MoonBit project builds and Mooncakes dependency packaging belong to moon2nix.

Quick start

nix run github:moonbit-community/moonbit-overlay#moon -- version
nix run github:moonbit-community/moonbit-overlay#moon -- lsp --version
nix shell github:moonbit-community/moonbit-overlay#latest
nix shell github:moonbit-community/moonbit-overlay#nightly

nix run github:moonbit-community/moonbit-overlay runs moon from latest. The moonx app runs executable packages from Mooncakes:

nix run github:moonbit-community/moonbit-overlay#moonx -- user/module/package

Development shell

nix flake init -t github:moonbit-community/moonbit-overlay

The template puts its flake in nix/; run nix develop ./nix.

Alternatively, apply the overlay to your own nixpkgs:

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    moonbit-overlay.url = "github:moonbit-community/moonbit-overlay";
  };

  outputs = { nixpkgs, moonbit-overlay, ... }:
    let
      system = "x86_64-linux";
      pkgs = import nixpkgs {
        inherit system;
        overlays = [ moonbit-overlay.overlays.default ];
      };
    in {
      devShells.${system}.default = pkgs.mkShell {
        packages = [ pkgs.moonbit-bin.latest ];
      };
    };
}

Without an overlay, use moonbit-overlay.packages.${system}.latest directly. The overlay uses the caller's nixpkgs for binary patching and runtime dependencies.

Non-flake users can apply import ./default.nix as an overlay to a pinned checkout of this repository.

Versions and platforms

Each public package is a complete toolchain:

pkgs.moonbit-bin.latest
pkgs.moonbit-bin.nightly
pkgs.moonbit-bin."v0.10.12+1634b282e+55ca257"

Flake packages use the same names; default is an alias for latest. Version names are the original release identifiers, without escaping dots or plus signs. Available snapshots are recorded in versions/toolchains. Versions older than 0.10.0 are retained as historical metadata but are not exposed. Version 0.10 is the first supported SDK generation with the current native helper layout, including moon-lsp.

Packages are exposed only when the snapshot has a hash for the requested host platform. The flake supports x86_64-linux and aarch64-darwin. Intel macOS is not exposed: the recorded snapshots have no binary hashes for that platform, and the locked nixpkgs no longer supports it.

latest resolves to a concrete release mirrored in this repository's GitHub releases. Pin the overlay revision (for example with flake.lock) to keep it fixed. nightly points to the newest nightly mirrored by this repository. Changed nightly builds are also exposed by date, for example pkgs.moonbit-bin."nightly-2026-09-22", and stored as immutable prereleases so older lock files remain fetchable.

Editor support

Configure the language server as command moon, argument lsp. It is included in the full toolchain; no separate LSP package is needed.

Migrating from the previous interface

Previous interface	Replacement
pkgs.moonbit-bin.moonbit.latest	pkgs.moonbit-bin.latest
packages.${system}.moonbit_latest	packages.${system}.latest
Escaped version attributes such as v0_10_12-1634b282e-55ca257	Quoted original version, "v0.10.12+1634b282e+55ca257"
legacyPackages.${system}.moonbit	packages.${system}
overlays.moonbit-overlay	overlays.default
templates.moonbit-dev	templates.default
Separate toolchains, core, compiler, or lsp packages	Complete toolchain package
moonPlatform, mkMoonPlatform, and project/registry builders	Use moon2nix for project builds

The project builders and dependency fixtures have moved to moon2nix. The obsolete patched moon implementation has been removed. The toolchain does not resolve project dependencies.

Design

Static release metadata is mapped to complete toolchain derivations. Internal steps fetch and patch the official binaries, install the matching core, bundle it, and wrap the tools for Nix.

License

MIT.