feat: add a nix flake

nix flake init --template github:nixos/templates#rust

.envrc

@@ -0,0 +1 @@
+use flake

.github/workflows/build_nix.yml

@@ -0,0 +1,13 @@
+name: "Build legacy Nix package on Ubuntu"
+
+on:
+  push:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: cachix/install-nix-action@v12
+      - name: Building package
+        run: nix-build . -A defaultPackage.x86_64-linux

default.nix

@@ -0,0 +1,7 @@
+(import (
+  fetchTarball {
+    url = "https://github.com/edolstra/flake-compat/archive/99f1c2157fba4bfe6211a321fd0ee43199025dbf.tar.gz";
+    sha256 = "0x2jn3vrawwv9xp15674wjz9pixwjyj3j771izayl962zziivbx2"; }
+) {
+  src =  ./.;
+}).defaultNix

flake.lock

@@ -0,0 +1,75 @@
+{
+  "nodes": {
+    "naersk": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1655042882,
+        "narHash": "sha256-9BX8Fuez5YJlN7cdPO63InoyBy7dm3VlJkkmTt6fS1A=",
+        "owner": "nix-community",
+        "repo": "naersk",
+        "rev": "cddffb5aa211f50c4b8750adbec0bbbdfb26bb9f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "ref": "master",
+        "repo": "naersk",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 0,
+        "narHash": "sha256-5Va2Qmy50AspTfyHvoWrwCpTuqArOg9LnvRPe8YW5no=",
+        "path": "/nix/store/19fkp4kfy3im81s5bnc5zg25k4g5hq86-source",
+        "type": "path"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1655211057,
+        "narHash": "sha256-Zs5wm2GuW2nER9uYpgAAxuEqEK3LTo3Y+lwaWn/YYHk=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "1712ecaa5118815292f57d6669c3c81d84d842b3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "naersk": "naersk",
+        "nixpkgs": "nixpkgs_2",
+        "utils": "utils"
+      }
+    },
+    "utils": {
+      "locked": {
+        "lastModified": 1653893745,
+        "narHash": "sha256-0jntwV3Z8//YwuOjzhV2sgJJPt+HY6KhU7VZUL0fKZQ=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "1ed9fb1935d260de5fe1c2f7ee0ebaae17ed2fa1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,26 @@
+{
+  inputs = {
+    naersk.url = "github:nix-community/naersk/master";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, utils, naersk }:
+    utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+        naersk-lib = pkgs.callPackage naersk { };
+      in
+      {
+        defaultPackage = naersk-lib.buildPackage ./.;
+
+        defaultApp = utils.lib.mkApp {
+          drv = self.defaultPackage."${system}";
+        };
+
+        devShell = with pkgs; mkShell {
+          buildInputs = [ cargo rustc rustfmt pre-commit rustPackages.clippy ];
+          RUST_SRC_PATH = rustPlatform.rustLibSrc;
+        };
+      });
+}

shell.nix

@@ -0,0 +1,7 @@
+(import (
+  fetchTarball {
+    url = "https://github.com/edolstra/flake-compat/archive/99f1c2157fba4bfe6211a321fd0ee43199025dbf.tar.gz";
+    sha256 = "0x2jn3vrawwv9xp15674wjz9pixwjyj3j771izayl962zziivbx2"; }
+) {
+  src =  ./.;
+}).shellNix