flake: migrate to flake-parts

flake.lock

@@ -1,5 +1,23 @@
 {
   "nodes": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1733312601,
+        "narHash": "sha256-4pDvzqnegAfRkPwO3wmwBhVi/Sye1mzps0zHWYnP88c=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "205b12d8b7cd4802fbcb8e8ef6a0f1408781a4f9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1724479785,
@@ -16,8 +34,21 @@
         "type": "github"
       }
     },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1733096140,
+        "narHash": "sha256-1qRH7uAUsyQI7R1Uwl4T+XvdNv778H0Nb5njNrqvylY=",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/5487e69da40cbd611ab2cadee0b4637225f7cfae.tar.gz"
+      },
+      "original": {
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/5487e69da40cbd611ab2cadee0b4637225f7cfae.tar.gz"
+      }
+    },
     "root": {
       "inputs": {
+        "flake-parts": "flake-parts",
         "nixpkgs": "nixpkgs",
         "rust-overlay": "rust-overlay"
       }

flake.nix

@@ -3,37 +3,36 @@
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+    flake-parts = {
+      url = "github:hercules-ci/flake-parts";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
     rust-overlay = {
       url = "github:oxalica/rust-overlay";
       inputs.nixpkgs.follows = "nixpkgs";
     };
   };
 
-  outputs = { nixpkgs, rust-overlay, ... }:
+  outputs = inputs@{ nixpkgs, rust-overlay, flake-parts, ... }:
-    let
+    flake-parts.lib.mkFlake { inherit inputs; } {
-      # System types to support.
+      systems = [
-      supportedSystems = [
         "x86_64-linux"
         "aarch64-darwin"
       ];
 
-      forAllSystems = function: nixpkgs.lib.genAttrs supportedSystems
+      perSystem = { system, pkgs, ... }: {
-        (system: function (import nixpkgs {
+        _module.args.pkgs = (import nixpkgs {
           inherit system;
           overlays = [ rust-overlay.overlays.default ];
-        }));
-    in
-    {
-      devShells = forAllSystems
-        (pkgs: {
-          default = import ./shell.nix {
-            inherit pkgs;
-            additionalBuildInputs = [
-              (pkgs.rust-bin.selectLatestNightlyWith (toolchain: toolchain.default.override {
-                extensions = [ "rust-src" "rust-analyzer" ];
-              }))
-            ];
-          };
         });
+        devShells.default = import ./shell.nix {
+          inherit pkgs;
+          additionalBuildInputs = [
+            (pkgs.rust-bin.selectLatestNightlyWith (toolchain: toolchain.default.override {
+              extensions = [ "rust-src" "rust-analyzer" ];
+            }))
+          ];
+        };
+      };
     };
 }