{

  inputs = {
    naersk.url = "github:nmattia/naersk/master";
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    utils.url = "github:numtide/flake-utils";
  };

  outputs = { self, nixpkgs, utils, naersk }:
    utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs { inherit system; };
        naersk-lib = pkgs.callPackage naersk { };
      in {

        defaultPackage = naersk-lib.buildPackage ./.;

        defaultApp = utils.lib.mkApp { drv = self.defaultPackage."${system}"; };

        devShell = with pkgs;
          mkShell {
            buildInputs = [
              # rust
              cargo
              cargo-watch
              rustc
              rust-analyzer
              rustfmt
              rustPackages.clippy

              # system
              pkg-config
              openssl
              cmake

              # dhall
              dhall
              dhall-json

              jo
            ];
            RUST_LOG = "info";
            RUST_SRC_PATH = rustPlatform.rustLibSrc;
          };

      });

}