Add simple Rust Crane project

The Nix code is taken from the Crane docs, and adapted for merging with the existing Haskell.Nix flake. The other files are from `cargo init`, with minor modifications, and `cargo generate-lockfile`.

The default dev shell contains tools for both languages.

We can now run `nix build .#rust` and `nix build .#haskell`, where the latter was previously `nix build .#aoc:exe:aoc`.

.gitignore

@@ -1,2 +1,3 @@
 dist*/
 result
+/target

Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "aoc"
+version = "0.1.0"

Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "aoc"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

flake.lock

@@ -83,6 +83,21 @@
         "type": "github"
       }
     },
+    "crane": {
+      "locked": {
+        "lastModified": 1763938834,
+        "narHash": "sha256-j8iB0Yr4zAvQLueCZ5abxfk6fnG/SJ5JnGUziETjwfg=",
+        "owner": "ipetkov",
+        "repo": "crane",
+        "rev": "d9e753122e51cee64eb8d2dddfe11148f339f5a2",
+        "type": "github"
+      },
+      "original": {
+        "owner": "ipetkov",
+        "repo": "crane",
+        "type": "github"
+      }
+    },
     "flake-compat": {
       "flake": false,
       "locked": {
@@ -588,6 +603,7 @@
     },
     "root": {
       "inputs": {
+        "crane": "crane",
         "flake-utils": "flake-utils",
         "haskellNix": "haskellNix",
         "nixpkgs": [

flake.nix

@@ -2,7 +2,8 @@
   inputs.haskellNix.url = "github:input-output-hk/haskell.nix";
   inputs.nixpkgs.follows = "haskellNix/nixpkgs-unstable";
   inputs.flake-utils.url = "github:numtide/flake-utils";
-  outputs = { self, nixpkgs, flake-utils, haskellNix }:
+  inputs.crane.url = "github:ipetkov/crane";
+  outputs = { self, nixpkgs, flake-utils, haskellNix, crane }:
     flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
       let
         overlays = [
@@ -17,7 +18,19 @@
         ];
         pkgs = import nixpkgs { inherit system overlays; inherit (haskellNix) config; };
         haskell = pkgs.hixProject.flake { };
+        rust = crane.mkLib pkgs;
       in
-      haskell
+      {
+        devShells.default = pkgs.mkShell {
+          inputsFrom = [
+            haskell.devShells.default
+            (rust.devShell { })
+          ];
+        };
+        packages = {
+          haskell = haskell.packages."aoc:exe:aoc";
+          rust = rust.buildPackage { src = rust.cleanCargoSource ./.; };
+        };
+      }
     );
 }

src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}