Add Rust and the toolchain via an overlay.

.gitignore

@@ -1,4 +1,5 @@
 .direnv/
+.vscode/
 coverage/
 debug/
 hooked-book/book/

flake.lock

@@ -18,13 +18,31 @@
         "type": "github"
       }
     },
+    "flake-utils_2": {
+      "inputs": {
+        "systems": "systems_2"
+      },
+      "locked": {
+        "lastModified": 1681202837,
+        "narHash": "sha256-H+Rh19JDwRtpVPAWp64F+rlEtxUWBAQW28eAi3SRSzg=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "cfacdce06f30d2b68473a46042957675eebb3401",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1705403940,
-        "narHash": "sha256-bl7E3w35Bleiexg01WsN0RuAQEL23HaQeNBC2zjt+9w=",
+        "lastModified": 1705635624,
+        "narHash": "sha256-DU0schxQOtBNO1c9hUsgYl+QMOXQMfRT7Qw/mg+ayno=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "f0326542989e1bdac955ad6269b334a8da4b0c95",
+        "rev": "4471857c0a4a8a0ffc7bdbeaf1b998746ce12a82",
         "type": "github"
       },
       "original": {
@@ -32,10 +50,46 @@
         "type": "indirect"
       }
     },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1681358109,
+        "narHash": "sha256-eKyxW4OohHQx9Urxi7TQlFBTDWII+F+x2hklDOQPB50=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "96ba1c52e54e74c3197f4d43026b3f3d92e83ff9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "flake-utils": "flake-utils_2",
+        "nixpkgs": "nixpkgs_2"
+      },
+      "locked": {
+        "lastModified": 1705630663,
+        "narHash": "sha256-f+kcR17ZtwMyCEtNAfpD0Mv6qObNKoJ41l+6deoaXi8=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "47cac072a313d9cce884b9ea418d2bf712fa23dd",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
       }
     },
     "systems": {
@@ -52,6 +106,21 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "systems_2": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -1,10 +1,14 @@
 {
-  inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs = {
+    flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+  };
 
-  outputs = { self, nixpkgs, flake-utils }:
+  outputs = { self, nixpkgs, flake-utils, rust-overlay }:
     flake-utils.lib.eachDefaultSystem (system:
       let
-        pkgs = nixpkgs.legacyPackages.${system};
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs { inherit system overlays; };
       in
       {
         devShells.default = import ./shell.nix { inherit pkgs; };

rustup-toolchain.toml

@@ -0,0 +1,3 @@
+[toolchain]
+channel = "stable"
+components = ["cargo", "clippy", "rustfmt", "rust-src"]

shell.nix

@@ -2,6 +2,14 @@
 
 with pkgs;
 
+let
+  rustup-toolchain = rust-bin.fromRustupToolchainFile ./rustup-toolchain.toml;
+in
 mkShell rec {
-  packages = [ cargo-make mdbook mdbook-linkcheck ];
+  packages = [
+    cargo-make
+    mdbook
+    mdbook-linkcheck
+    rustup-toolchain
+  ];
 }