Use flake

.envrc

@@ -1 +1 @@
-use nix
+use flake

flake.lock

@@ -0,0 +1,83 @@
+{
+  "nodes": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1730504689,
+        "narHash": "sha256-hgmguH29K2fvs9szpq2r3pz2/8cJd2LPS+b4tfNFCwE=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "506278e768c2a08bec68eb62932193e341f55c90",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1732014248,
+        "narHash": "sha256-y/MEyuJ5oBWrWAic/14LaIr/u5E0wRVzyYsouYY3W6w=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "23e89b7da85c3640bbc2173fe04f4bd114342367",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1728538411,
+        "narHash": "sha256-f0SBJz1eZ2yOuKUr5CA9BHULGXVSn6miBuUWdTyhUhU=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "b69de56fac8c2b6f8fd27f2eca01dcda8e0a4221",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": "nixpkgs_2"
+      },
+      "locked": {
+        "lastModified": 1732328983,
+        "narHash": "sha256-RHt12f/slrzDpSL7SSkydh8wUE4Nr4r23HlpWywed9E=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "ed8aa5b64f7d36d9338eb1d0a3bb60cf52069a72",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,62 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-parts = {
+      url = "github:hercules-ci/flake-parts";
+      inputs.nixpkgs-lib.follows = "nixpkgs";
+    };
+    rust-overlay.url = "github:oxalica/rust-overlay";
+  };
+
+  outputs =
+    inputs@{ self, flake-parts, ... }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+      ];
+
+      perSystem =
+        {
+          config,
+          self',
+          inputs',
+          pkgs,
+          system,
+          ...
+        }:
+        {
+          _module.args.pkgs = import self.inputs.nixpkgs {
+            inherit system;
+            overlays = [
+              (import inputs.rust-overlay)
+            ];
+          };
+          devShells.default =
+            let
+              libPath =
+                with pkgs;
+                lib.makeLibraryPath [
+                  pkg-config
+                  openssl
+                ];
+            in
+            pkgs.mkShell {
+              inputsFrom = builtins.attrValues self'.packages;
+              packages = with pkgs; [
+                # (rust-bin.selectLatestNightlyWith (toolchain: toolchain.default))
+                pkg-config
+                openssl
+                cargo
+                cargo-watch
+                rustc
+                rust-analyzer
+                clippy
+              ];
+              LD_LIBRARY_PATH = libPath;
+              RUST_BACKTRACE = 1;
+              LIBCLANG_PATH = "${pkgs.libclang.lib}/lib";
+            };
+        };
+      };
+}

shell.nix

@@ -1,24 +0,0 @@
-/*
-based on
-https://discourse.nixos.org/t/how-can-i-set-up-my-rust-programming-environment/4501/9
-*/
-let
-  rust_overlay = import (builtins.fetchTarball "https://github.com/oxalica/rust-overlay/archive/master.tar.gz");
-  pkgs = import <nixpkgs> { overlays = [ rust_overlay ]; };
-  rustVersion = "latest"; # using a specific version: "1.62.0"
-  rust = pkgs.rust-bin.stable.${rustVersion}.default.override {
-    extensions = [
-      "rust-src" # for rust-analyzer
-      "rust-analyzer" # usable by IDEs like zed-editor
-    ];
-  };
-in
-pkgs.mkShell {
-  buildInputs = [
-    rust
-  ] ++ (with pkgs; [
-    pkg-config
-    openssl
-  ]);
-  RUST_BACKTRACE = 1;
-}