Add Nix dev shell and direnv support

.envrc

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

.gitignore

@@ -1 +1,2 @@
 /target
+/.direnv

flake.lock

@@ -0,0 +1,65 @@
+{
+  "nodes": {
+    "fenix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "rust-analyzer-src": "rust-analyzer-src"
+      },
+      "locked": {
+        "lastModified": 1716359173,
+        "narHash": "sha256-pYcjP6Gy7i6jPWrjiWAVV0BCQp+DdmGaI/k65lBb/kM=",
+        "owner": "nix-community",
+        "repo": "fenix",
+        "rev": "b6fc5035b28e36a98370d0eac44f4ef3fd323df6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "fenix",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1716451822,
+        "narHash": "sha256-0lT5RVelqN+dgXWWneXvV5ufSksW0r0TDQi8O6U2+o8=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "3305b2b25e4ae4baee872346eae133cf6f611783",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixpkgs-unstable",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "fenix": "fenix",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "rust-analyzer-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1716107283,
+        "narHash": "sha256-NJgrwLiLGHDrCia5AeIvZUHUY7xYGVryee0/9D3Ir1I=",
+        "owner": "rust-lang",
+        "repo": "rust-analyzer",
+        "rev": "21ec8f523812b88418b2bfc64240c62b3dd967bd",
+        "type": "github"
+      },
+      "original": {
+        "owner": "rust-lang",
+        "ref": "nightly",
+        "repo": "rust-analyzer",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,32 @@
+{
+  inputs = {
+    nixpkgs.url = "nixpkgs/nixpkgs-unstable";
+
+    fenix = {
+      url = "github:nix-community/fenix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, fenix }:
+  let
+    overlays = [ fenix.overlays.default ];
+
+    getPkgsFor = (system: import nixpkgs {
+      inherit system overlays;
+    });
+
+    forEachSystem = func: nixpkgs.lib.genAttrs [
+      "x86_64-linux"
+      "aarch64-linux"
+
+      "aarch64-darwin"
+      "x86_64-darwin"
+    ] (system: func (getPkgsFor system));
+
+  in {
+    devShells = forEachSystem (pkgs: {
+      default = pkgs.callPackage ./shell.nix {};
+    });
+  };
+}

rust-toolchain.toml

@@ -0,0 +1,4 @@
+[toolchain]
+channel = "stable"
+profile = "default"
+targets = ["x86_64-unknown-linux-gnu", "aarch64-unknown-linux-gnu"]

shell.nix

@@ -0,0 +1,12 @@
+{ mkShell, fenix }:
+
+let
+  toolchain = fenix.fromToolchainFile {
+    file = ./rust-toolchain.toml;
+    sha256 = "opUgs6ckUQCyDxcB9Wy51pqhd0MPGHUVbwRKKPGiwZU=";
+  };
+in
+
+mkShell {
+  packages = [ toolchain ];
+}