let's do ugly versioning in my playground

flake.nix

@@ -0,0 +1,33 @@
+{
+  description = "common lisp dbus playground";
+  inputs.nixpkgs.url = "github:nixos/nixpkgs";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem
+      (system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+          # https://nixos.org/manual/nixpkgs/stable/#lisp-overriding-package-attributes
+          # getting version with automatic introspection mixin
+          dbus' = pkgs.sbcl.pkgs.dbus.overrideLispAttrs (oldAttrs: rec {
+                                                  version = "1.4";
+                                                  src = pkgs.fetchFromGitHub {
+                                                    owner = "death";
+                                                    repo = "dbus";
+                                                    rev = "master";
+                                                    hash = "sha256-xbg3tPYfRNGJo+9F/58w2bDeZqV33Z871+ClSg4ACPk=";
+                                                  };
+                                                });
+          sbcl' = pkgs.sbcl.withPackages (ps: [ ps.alexandria dbus' ]);
+        in
+          {
+            devShells.default = pkgs.mkShell {
+              buildInputs = [
+                sbcl'
+              ];
+            };
+          }
+      );
+  # see https://serokell.io/blog/practical-nix-flakes
+}