tt/flake.nix

# ml2 ts=2 sts=2 sw=2

{
  description = "A simple Go package";

  # Nixpkgs / NixOS version to use.
  inputs.nixpkgs.url = "nixpkgs/nixos-unstable";

  outputs = { self, nixpkgs }:
    let

      # to work with older version of flakes
      lastModifiedDate = self.lastModifiedDate or self.lastModified or "19700101";

      # Generate a user-friendly version number.
      version = builtins.substring 0 8 lastModifiedDate;

      # System types to support.
      supportedSystems = [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];

      # Helper function to generate an attrset '{ x86_64-linux = f "x86_64-linux"; ... }'.
      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;

      # Nixpkgs instantiated for supported system types.
      nixpkgsFor = forAllSystems (system: import nixpkgs { inherit system; });

    in {
      # Provide some binary packages for selected system types.
      packages = forAllSystems (system:
      let
        pkgs = nixpkgsFor.${system};
      in
      {
        tt = pkgs.callPackage ./nix/package.nix { version = version; };
      });

      # Add dependencies that are only needed for development
      devShells = forAllSystems (system:
      let
        pkgs = nixpkgsFor.${system};
      in
      {
        default = pkgs.mkShell {
          buildInputs = with pkgs; [ go gopls gotools go-tools qbe (if system == "x86_64-linux" then [fasm] else []) ];
        };
      });

      # The default package for 'nix build'. This makes sense if the
      # flake provides only one package or there is a clear "main"
      # package.
      defaultPackage = forAllSystems (system: self.packages.${system}.tt);
    };
}