{
  description = "Advent Of Code 2023";

  inputs = {
    nixpkgs.url = "nixpkgs/nixos-unstable";
  };

  outputs = { self, nixpkgs }:
    let

      forAllSystems = function:
        nixpkgs.lib.genAttrs [
          "x86_64-linux"
          "aarch64-darwin"
        ] (system: function nixpkgs.legacyPackages.${system});

    in
      {

        devShells = forAllSystems (pkgs: with pkgs; {
          default = mkShell {
            nativeBuildInputs = [ rustc cargo clippy ];
            buildInputs = [ hyperfine glow libiconv ];
            RUST_SRC_PATH = "${rustPlatform.rustLibSrc}";
            shellHook = ''
bench() {
  cargo build --release
  DAY=$((($(date +%s)-$(date +%s --date "2023-11-30"))/(3600*24)))
  hyperfine --parameter-list day $(seq --format "%02.f" 1 $DAY | paste -sd ',' -) "./target/release/day{day} ./data/{day}.in" --runs 20 --warmup 10 --shell=none --export-markdown ./target/bench-output.md 2> /dev/null
  glow ./target/bench-output.md
}
'';
          };
        });
      };
}