mkflake.nix

mkflake.nix is a lightweight (8 lines) alternative to flake-utils and flake-parts.

There's only one function: lib.mkflake, and you use it as follows:

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/release-23.05";
    mkflake.url = "github:jonascarpay/mkflake";
  };

  outputs = { nixpkgs, mkflake, ... }: mkflake.lib.mkflake {
    topLevel = { ... };
    perSystem = system:
      let
        pkgs = import nixpkgs { inherit system; };
      in
        { devShells.default = pkgs.mkShell { ... }; };
    systems = [ "x86_64-linux" ];
  };
}

As you'd expect, topLevel attributes appear in the flake outputs as-is, and perSystem outputs are generated for each system in systems. All arguments are optional, defaulting to { }, _: { }, and {x86_64, aarch64}-{linux, darwin}, respectively. The spelling toplevel is allowed but deprecated.

You can get the above as a template using

nix flake init -t github:jonascarpay/mkflake

Why not flake-utils?

I end up writing this topLevel/perSystem pattern every time I use flake-utils, which is annoying.

Why not flake-parts?

flake-parts has something close to the topLevel/perSystem pattern, but also includes hundreds of lines of other features that I don't need.