nix: init tooling

nix/package.nix

@@ -0,0 +1,28 @@
+{
+  lib,
+  rustPlatform,
+}: let
+  fs = lib.fileset;
+in
+  rustPlatform.buildRustPackage (finalAttrs: {
+    pname = "nff";
+    version = "0.1.0";
+
+    src = fs.toSource {
+      root = ../.;
+      fileset = fs.unions [
+        (fs.fileFilter (file: builtins.any file.hasExt ["rs"]) ../src)
+        ../Cargo.lock
+        ../Cargo.toml
+      ];
+    };
+
+    cargoLock.lockFile = "${finalAttrs.src}/Cargo.lock";
+    useFetchCargoVendor = true;
+    enableParallelBuilding = true;
+
+    meta = {
+      description = "Experimental nftables ruleset formatter and prettier";
+      mainProgram = "nff";
+    };
+  })

nix/shell.nix

@@ -0,0 +1,19 @@
+{
+  mkShell,
+  rust-analyzer,
+  rustfmt,
+  clippy,
+  cargo,
+  rustPlatform,
+}:
+mkShell {
+  name = "rust";
+  packages = [
+    rust-analyzer
+    rustfmt
+    clippy
+    cargo
+  ];
+
+  RUST_SRC_PATH = "${rustPlatform.rustLibSrc}";
+}