{
  description = "A flake to use a development version of Chicken.";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    systems.url = "github:nix-systems/default-linux";
  };

  outputs = inputs @ {
    self,
      nixpkgs,
      systems,
      ...
  }: let
    inherit (nixpkgs) lib;
    eachSystem = lib.genAttrs (import systems);
    pkgsFor = eachSystem (system:
      import nixpkgs {
        localSystem.system = system;
        overlays = with self.overlays; [chicken];
      });
    mkDate = longDate: (lib.concatStringsSep "-" [
      (builtins.substring 0 4 longDate)
      (builtins.substring 4 2 longDate)
      (builtins.substring 6 2 longDate)
    ]);
    version = "6.0.0";
  in {
    overlays = {
      default = self.overlays.chicken;

      chicken = final: prev: {
        chicken = final.callPackage ./nix/default.nix {
          stdenv = final.gcc13Stdenv;
          version = version + "+date=" + (mkDate (self.lastModifiedDate or "19700101")) + "_" + (self.shortRev or "dirty");
        };
      };
    };

    devShells = eachSystem (system: {
      default = let
        pkgs = import nixpkgs {
          overlays = [ self.overlays.chicken ];
        };
      in pkgs.mkShell {
        packages = [ pkgs.chicken ];
      };
    });
  };
}