flake.nix


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{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
    flake-parts = { url = "github:hercules-ci/flake-parts"; inputs.nixpkgs-lib.follows = "nixpkgs"; };
    treefmt-nix.url = "github:numtide/treefmt-nix";
  };

  outputs = inputs:
    inputs.flake-parts.lib.mkFlake { inherit inputs; } {
      systems = [ "x86_64-linux" ];
      imports = [
        inputs.treefmt-nix.flakeModule
      ];

      perSystem = { pkgs, ... }: {
        packages.default = pkgs.haskellPackages.callCabal2nix "example" ./. { };

        devShells.default = pkgs.haskellPackages.shellFor {
          packages = ps: [ ];
          buildInputs = with pkgs.haskellPackages; [
            cabal-install
            haskell-language-server
            megaparsec
            stack
          ];
        };
        treefmt = {
          projectRootFile = "flake.nix";
          programs.nixpkgs-fmt.enable = true;
          programs.cabal-fmt.enable = true;
          programs.ormolu.enable = true;
          programs.hlint.enable = true;
          programs.ormolu.package = pkgs.haskellPackages.fourmolu;
        };
      };
    };
}