flake: dev env + build/test gcgen pkg

flake.nix

@@ -0,0 +1,70 @@
+{
+  description = "bindings generation dev env";
+
+  inputs = { nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05"; };
+
+  outputs = { self, nixpkgs }:
+    let
+      allSystems = [
+        "x86_64-linux" # AMD/Intel Linux
+        "x86_64-darwin" # AMD/Intel macOS
+        "aarch64-linux" # ARM Linux
+        "aarch64-darwin" # ARM macOS
+      ];
+
+      forAllSystems = fn:
+        nixpkgs.lib.genAttrs allSystems
+        (system: fn { pkgs = import nixpkgs { inherit system; }; });
+
+      rev = "${self.lastModifiedDate}";
+
+    in {
+      # used when calling `nix fmt <path/to/flake.nix>`
+      formatter = forAllSystems ({ pkgs }: pkgs.nixfmt);
+
+      # nix develop <flake-ref>#<name>
+      # -- 
+      # $ nix develop <flake-ref>#blue
+      # $ nix develop <flake-ref>#yellow
+      devShells = forAllSystems ({ pkgs }:
+        let python = pkgs.python311Packages;
+        in {
+          default = pkgs.mkShell {
+            name = "nixdev";
+            nativeBuildInputs = (with pkgs.python311Packages; [
+              python-lsp-server
+              pyls-isort
+              pylsp-mypy
+              pytest
+              black
+              sphinx
+            ]);
+          };
+        });
+
+      # nix run|build <flake-ref>#<pkg-name>
+      # -- 
+      # $ nix run <flake-ref>#hello
+      # $ nix run <flake-ref>#cowsay
+      packages = forAllSystems ({ pkgs }:
+        let python = pkgs.python311Packages;
+        in rec {
+          gcgen = (python.buildPythonPackage rec {
+            pname = "gcgen";
+            version = rev;
+            src = ./.;
+            doCheck = true;
+            propagatedBuildInputs = [ ];
+            checkInputs = (with python; [ pytest ]);
+            checkPhase = ''
+              TERM=unknown python -m pytest
+            '';
+            meta = with pkgs.lib; {
+              description = "a general code generator";
+              homepage = "https://jwdevantier.github.io/gcgen/";
+              license = licenses.mit;
+            };
+          });
+        });
+    };
+}