Add Nix flake and direnv setup.

.envrc

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+use flake

.gitignore

@@ -1,9 +1,6 @@
-# Generated by Cargo
+.direnv/
+.vscode/
+aoc/
+coverage/
 debug/
 target/
-
-# Code coverage results
-coverage/
-
-# Advent of Code data
-aoc/

flake.lock

@@ -0,0 +1,128 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1705309234,
+        "narHash": "sha256-uNRRNRKmJyCRC/8y1RqBkqWBLM034y4qN7EprSdmgyA=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "1ef2e671c3b0c19053962c07dbda38332dcebf26",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "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": 1705635624,
+        "narHash": "sha256-DU0schxQOtBNO1c9hUsgYl+QMOXQMfRT7Qw/mg+ayno=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "4471857c0a4a8a0ffc7bdbeaf1b998746ce12a82",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "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",
+        "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": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "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",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,17 @@
+{
+  inputs = {
+    flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+  };
+
+  outputs = { self, nixpkgs, flake-utils, rust-overlay }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        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

@@ -0,0 +1,14 @@
+{ pkgs ? import <nixpkgs> { } }:
+
+with pkgs;
+
+let
+  rustup-toolchain = rust-bin.fromRustupToolchainFile ./rustup-toolchain.toml;
+in
+mkShell rec {
+  packages = [
+    cargo-edit
+    cargo-make
+    rustup-toolchain
+  ];
+}