{
  description = "D4 AOC with Lua!";
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    flake-utils.url = "github:numtide/flake-utils";
    clj-nix = {
      url = "github:jlesquembre/clj-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };
  outputs = { nixpkgs, flake-utils, clj-nix, ... } @ inputs:
    flake-utils.lib.eachSystem flake-utils.lib.defaultSystems (sys:
      let
        overlays = [ ];
        pkgs = import nixpkgs { system = sys; overlays = overlays; };
        shellHookAfter = ''
          echo "The input files should be placed under ./data/{submission,example}.txt"
          echo "This problem shares one input between two parts"
        '';
        clj_pkgs = import clj-nix { system = sys; };
        py_pkgs = [ pkgs.python310 ];
        clojure_pkgs = [ ];

      in
      {
        # Jack of all trades
        devShell = pkgs.mkShell
          {
            nativeBuildInputs = py_pkgs ++ fennel_pkgs;
            shellHook = ''
              echo "> Default runtime. This contains both fennel and python3 env"
              echo "Run ./run-py.sh for Python's output and ./run-fnl.sh for Fennel's output"
            '' + shellHookAfter;
          };
        devShells = {
          # nix develop ./#lua
          # lua = pkgs.mkShell {
          #   nativeBuildInputs = lua_pkgs;
          #   shellHook = ''
          #     echo "> Lua runtime"
          #     echo "Run ./run-lua.sh to see the output of the solution"
          #   '' + shellHookAfter;
          # };

          # nix develop ./#fennel
          fennel = pkgs.mkShell
            {
              nativeBuildInputs = fennel_pkgs;
              shellHook = ''
                echo "> Fennel runtime"
                echo "Run ./run-fnl.sh to see output of Fennel solution"
              '' + shellHookAfter;
            };

          # nix develop ./#python
          python = pkgs.mkShell {
            nativeBuildInputs = py_pkgs;
            shellHook = ''
              echo "> Python3 runtime"
              echo "Run ./run-py.sh to see the output of the solution"
            '' + shellHookAfter;

          };
        };
      }
    );
}