{
  description = "Haskell Project Template";
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    treefmt.url = "github:numtide/treefmt-nix";
  };
  outputs =
    inputs@{ nixpkgs, ... }:
    let
      inherit (nixpkgs) lib;
      systems = [ "x86_64-linux" ];
      forAllSystems =
        f:
        lib.genAttrs systems (
          system:
          f {
            pkgs = import nixpkgs {
              inherit system;
            };
          }
        );
      treefmtEval = forAllSystems ({ pkgs }: inputs.treefmt.lib.evalModule pkgs ./flake/treefmt.nix);
    in
    {
      packages = forAllSystems (
        { pkgs }:
        {
          default = pkgs.callPackage ./flake/package.nix { };
        }
      );
      devShells = forAllSystems (
        { pkgs }:
        {
          default = pkgs.callPackage ./flake/shell.nix { };
        }
      );
      formatter = forAllSystems ({ pkgs }: treefmtEval.${pkgs.system}.config.build.wrapper);
    };
}