Add a shell.nix

.envrc

@@ -0,0 +1,5 @@
+# If we are a computer with nix-shell available, then use that to setup
+# the build environment with exactly what we need.
+if has nix; then
+  use nix
+fi

flake.lock

@@ -1,5 +1,21 @@
 {
   "nodes": {
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1673956053,
+        "narHash": "sha256-4gtG9iQuiKITOjNQQeQIpoIB6b16fm+504Ch3sNKLd8=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "35bb57c0c8d8b62bbfd284272c928ceb64ddbde9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "locked": {
         "lastModified": 1659877975,
@@ -33,6 +49,7 @@
     },
     "root": {
       "inputs": {
+        "flake-compat": "flake-compat",
         "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs"
       }

flake.nix

@@ -4,6 +4,12 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
     flake-utils.url = "github:numtide/flake-utils";
+
+    # Used for shell.nix
+    flake-compat = {
+      url = github:edolstra/flake-compat;
+      flake = false;
+    };
   };
 
   outputs = {
@@ -32,6 +38,16 @@
 
       # nix fmt
       formatter = pkgs.alejandra;
+
+      devShells.default = pkgs.mkShell {
+        nativeBuildInputs = with pkgs; [
+          curl
+          jq
+        ];
+      };
+
+      # For compatibility with older versions of the `nix` binary
+      devShell = self.devShells.${system}.default;
     });
   in
     outputs

shell.nix

@@ -0,0 +1,12 @@
+(import
+  (
+    let
+      flake-compat = (builtins.fromJSON (builtins.readFile ./flake.lock)).nodes.flake-compat;
+    in
+      fetchTarball {
+        url = "https://github.com/edolstra/flake-compat/archive/${flake-compat.locked.rev}.tar.gz";
+        sha256 = flake-compat.locked.narHash;
+      }
+  )
+  {src = ./.;})
+.shellNix