{
  description = "a sisu like parser and document generator";
  inputs.flake-utils.url = "github:numtide/flake-utils";
  inputs.nixpkgs.url = "github:nixos/nixpkgs";
  #inputs.nixpkgs.url = "/nixpkgs-ra/nixpkgs";
  outputs = { self, nixpkgs, flake-utils }: {
    packages.x86_64-linux.spine =
      let
        pkgs = import nixpkgs {
          system = "x86_64-linux";
        };
        #targetOf = package: "${package.targetPath or "."}/${package.targetName or package.name}";
      in pkgs.stdenv.mkDerivation {
        pname       = "spine";
        version     = "0.12.0";
        description = "a sisu like parser and document generator";
        inherit self;
        src = self;
        shell = ./shell.nix;
        buildPhase = ''
          runHook preBuild
          HOME="$PWD"
          DFLAGS="-O2 -inline"
          for DC_ in dmd ldmd2 gdmd; do
            echo "- check for D compiler $DC_"
            DC=$(type -P $DC_ || echo "")
            if [ ! "$DC" == "" ]; then break; fi
          done
          if [ "$DC" == "" ]; then
            exit "Error: could not find D compiler"
          fi
          echo "$DC_ used as D compiler to build $pname"
          dub build --compiler=$DC --build=release --combined --skip-registry=all
          runHook postBuild
        '';
        checkPhase = ''
          runHook preCheck
          HOME="$PWD"
          dub test --combined --skip-registry=all
          runHook postCheck
        '';
        installPhase = ''
          runHook preInstall
          mkdir -p $out/bin
          install -m755 ./bin/spine $out/bin/spine
          #cp -r bin/spine $out/bin/.
          runHook postInstall
        '';
        postInstall = ''
          echo `ls -la $out/bin/spine`
          echo ""
          echo "nix build or nix develop? (suggestions):"
          echo '- nix build'
          echo '  nix build .#spine --print-build-logs'
          echo '    nix build --print-build-logs'
          echo '- nix run'
          echo '  nix run .#spine --print-build-logs'
          echo '  nix run default.nix --print-build-logs'
          echo '- nix shell'
          echo '  nix shell --print-build-logs --command spine -v'
          echo '- nix develop'
          echo '  nix develop --build -f derivation.nix -I .envrc --print-build-logs'
          echo '    nix develop ; eval "$buildPhase"'
          echo 'spine -v'
          echo 'nix-instantiate | nix show-derivation | jq'
          echo `ls -la $out/bin/spine`
          echo "built:"
          $out/bin/spine -v
        '';
        nativeBuildInputs = with pkgs; [ ldc dub ];
        buildInputs = with pkgs; [ sqlite ];
     };
     packages.x86_64-linux.default = self.packages.x86_64-linux.spine;
  };
}

#nix flake update
#nix flake check
#nix flake show
#nix develop
#nix build .#default --print-build-logs